disease more easily to others than with previous variants. This
development poses a great concern for the unvaccinated, who generally
do not have the protections against severe outcomes that vaccination
affords. Before Delta, vaccinated individuals were shown to have lower
estimated viral loads when infected than those who were unvaccinated,
which suggested that infected vaccinated individuals were likely not a
major concern for transmission (Levine-Tiefenbrun et al., March 29,
2021). Transmission studies prior to the emergence of Delta appear to
bear this out. A Scottish study performed during a time period when the
Alpha variant was predominant in the region, showed that a fully
vaccinated individual was 3.2 times less likely than an unvaccinated
individual to transmit the virus to unvaccinated family members (Shah
et al., September 10, 2021; supplementary appendix). A population-based
study from the Netherlands found that vaccination decreased secondary
transmission to household members from 31% to 11% (de Gier et al.,
August 5, 2021). Additionally, a study from the UK found that household
transmission decreased by as much as 50% when the infected individual
was vaccinated (Harris et al., June 23, 2021).
    More recent research suggests that the Delta variant may have
reduced the level of protection vaccination affords against
transmission of the virus to others, but still significantly reduces
transmission risk in comparison to infected unvaccinated individuals. A
UK study found that fully vaccinated individuals infected by the Delta
variant are able to transmit the virus to both vaccinated and, to a
greater degree, unvaccinated persons (Singanayagam et al., September 6,
2021). Still, the rate at which transmission to unvaccinated
individuals occurred was nearly double the rate of transmission to
vaccinated individuals (35.7% compared to 19.7%). Similarly, Eyre et
al., (September 29, 2021) found that during the predominance of Alpha,
full vaccination with the Pfizer-BioNTech vaccines resulted in a
significant reduction in transmission to others (an adjusted Odds Ratio
(aOR) of 0.18, meaning that being unvaccinated increased the odds of
transmission by over five times). With the rise of the Delta variant,
that reduction in transmission to others was less than with the Alpha
variant, but still significantly more than for unvaccinated individuals
(aOR of 0.35, meaning that being unvaccinated increased the odds of
transmission by almost three times).
    The greater ability for vaccinated individuals to transmit the
Delta variant of SARS-CoV-2 to others (compared to previous variants)
appears to be linked to the generation of similar viral loads (as
estimated by Ct threshold) in the vaccinated compared to the
unvaccinated (Ct threshold is the number of RT-PCR cycles that need to
be run in order to amplify the RNA enough to be detected--fewer cycles
means a greater initial amount of virus was collected) (Singanayagam et
al., September 6, 2021). This observation has been made in several
studies. A study from Israel observed that viral loads among those
infected with the Delta variant were only decreased in people who had
been vaccinated recently (within the past two months) or in those who
had recently received a booster dose (Levine-Tiefenbrun et al.,
September 1, 2021). In a study of SARS-CoV-2 infections in Los Angeles
County, performed when the Delta variant was predominant, vaccination
status did not appear to affect the estimated viral loads, suggesting
that infected individuals who are vaccinated

may be just as likely to transmit the virus (Griffin et al., August 27,
2021). Additionally, estimated viral loads did not appear to be
significantly different with respect to vaccination status in a
Wisconsin study (Riemersma et al., July 31, 2021). Regardless of viral
loads in vaccinated and unvaccinated individuals, the fact remains
clear that unvaccinated people pose a higher risk of transmission to
others than vaccinated people, simply because they are much more likely
to get COVID-19 in the first place.
    These studies, however, appear to overstate increases in
transmission risk from vaccinated individuals related to the Delta
variant. From May to July 2021, UK researchers tested individuals at
random to better characterize viral load estimates in people with
asymptomatic as well as symptomatic infections; they found that
vaccination was associated with a significantly lower estimated viral
load (Elliott et al., September 10, 2021). This more comprehensive
study (i.e., Elliott et al., September 10, 2021) may have been able to
better characterize the course of infection and to incorporate
vaccinated individuals whose viral loads were decreasing quickly. The
findings in Elliott et al. are consistent with studies observing that
viral load may fall more quickly in vaccinated individuals, resulting
in a shorter infectious period and possibly fewer transmission events
(Chia et al., July 31, 2021; Eyre et al., September 29, 2021).
c. Conclusion for the Impact of Vaccines
    The studies discussed above indicate that vaccines continue to
effectively protect vaccinated individuals against SARS-CoV-2
infections, while the risk of infection, hospitalization, and death
increased among unvaccinated people as the Delta variant became
predominant in the U.S. The Delta variant is even more dangerous to
unvaccinated individuals than previous variants because of the higher
transmission potential from both unvaccinated and vaccinated people.
Because unvaccinated individuals are at much higher risk of severe
health outcomes from infection with SARS-CoV-2, and also pose a greater
transmission risk to those around them, it is critical to assure that
as many people as possible are fully vaccinated in order to prevent
transmission at work.
V. Coverage of OSHA's Grave Danger Finding
    Based on the information discussed above, OSHA finds that many
unvaccinated workers across the U.S. economy are facing a grave danger
of severe health effects or death from exposure to SARS-CoV-2. Fully
vaccinated workers are not included in this grave danger finding
because, as described throughout this section, those who are fully
vaccinated are much better protected from the effects of SARS-CoV-2
and, in particular, the most severe effects, than are those who are
unvaccinated.\15\ Beyond that, OSHA's grave danger determination
exempts several categories of workers based on characteristics of their
work or workplace: (1) Workers who do not report to a workplace where
other individuals are present or who telework from home; and (2)
workers who perform their work exclusively outdoors. The basis for
these exemptions is explained below. In this section, OSHA also
addresses the basis for OSHA's grave danger finding for workers who are
unvaccinated yet had a prior COVID-19 infection, and explains the
Agency's more nuanced grave danger finding in the healthcare industry.
---------------------------------------------------------------------------

    \15\ The exclusion of vaccinated workers from this grave danger
finding does not mean that vaccinated workers face no risk from
exposure to SARS-CoV-2. The best available evidence clearly shows
that vaccination provides great protection from infection and severe
outcomes, but breakthrough infections do occur and vaccinated
individuals can still transmit the virus to others. In some cases,
the level of risk to vaccinated workers may even rise to the level
of a significant risk, the standard OSHA must meet for promulgation
of a permanent standard under section 6(b)(5) of the OSH Act (29
U.S.C. 655(b)(5)).
---------------------------------------------------------------------------

a. Employees Who Telework and Employees Who Do Not Report to a
Workplace Where Other People Are Present.
    Employees who report to workplaces where no other people are
present face no grave danger from occupational exposure to COVID-19
because such exposure requires the presence of other people. For those
who work from their homes, or from workplaces where no other people are
present (such as a remote worksite), the chances of being exposed to
SARS-CoV-2 through a work activity are negligible. Therefore, OSHA is
exempting those workers who do not come into contact with others for
work purposes from its grave danger finding as well as the scope of the
ETS (for more information, see the Summary and Explanation for Scope
and Application, Section VI.B. of this preamble).
b. Employees Who Work Exclusively Outside
    Employees who work exclusively outside face a much lower risk of
exposure to SARS-CoV-2 at work, because their workplaces typically do
not include any of the characteristics that normally enable
transmission to occur (e.g., indoors, lack of ventilation, crowding).
Bulfone et al. attributed the lower risk of transmission in outdoor
settings (i.e., open air or structures with one wall) to increased
ventilation with fresh air and a greater ability to maintain physical
distancing (November 29, 2020). While the best available evidence
firmly establishes a grave danger in indoor settings, the CDC has
stated that the risk of outdoor transmission is ``low'' (CDC, September
1, 2021) and OSHA is unable to establish a grave danger in outdoor
settings from exposure during normal work activities.
    OSHA recognizes that outdoor transmission has been identified in a
few specific incidents (e.g., 2 of 7,324 cases, Qian et al., October
27, 2020). However, general reviews of transmission studies that
include large-scale and high-density outdoor gatherings indicate that
indoor transmission overwhelmingly is responsible for SARS-CoV-2
transmission. Additionally, the lack of evidence tied to specific case
studies illustrating outdoor transmission in comparison to the bevy of
case studies on indoor transmission makes it difficult to support a
conclusion that outdoor transmission rises to the level of a grave
danger.
    Bulfone et al. reviewed a collection of SARS-CoV-2 studies that
evaluated infections in outdoor and indoor settings (November 29,
2020), and found that transmission is significantly less likely to
occur in outdoor settings than in indoor settings. The studies overall
found that the risk of outdoor transmission was less than 10% of the
risk of transmission in indoor settings, with three of the studies
concluding risk was 5% or less of the risk of transmission in indoor
settings. While acknowledging significant gaps in knowledge, the
authors of a different study suggested that increases in transmission
related to large events such as the Sturgis motorcycle rally may be
related to lack of local efforts to prevent transmission indoors (e.g.,
requiring the wearing of masks, closing indoor dining), rather than the
outdoor setting for the rally (Dave et al., December 2, 2020). In
contrast, transmission rates did not increase as expected following the
Summer 2020 protests on racial injustice. This outcome was attributed,
in part, to participants having been less likely to enter indoor
commercial establishments.

    Weed and Foad (September 10, 2020) found that transmission of SARS-
CoV-2 related to large scale outdoor gatherings could be largely
attributed to individual behaviors related to that event, such as
communal travel and indoor congregation at other facilities (e.g.,
restaurants, shared accommodations), rather than to the time spent
outdoors at those gatherings. Similarly, a Public Health England
evaluation of the literature on SARS-CoV-2 and surrogate respiratory
viruses (December 18, 2020) also concluded that when transmission does
occur at outdoor events, outdoor activities were mixed with indoor
setting use. Public Health England concluded that the vast majority of
transmission happens in indoor settings, with very little evidence for
outdoor transmission.
    A systemic review of SARS-CoV-2 clusters identified 201 events
through May 26, 2020 (Leclerc et al., April 28, 2021), only 4 of which
occurred at predominantly outdoor settings. For those 4 clusters, the
authors noted that they were not able to evaluate specific transmission
events and attributed it to local health agencies being overwhelmed by
the pandemic. OSHA notes that the designations of settings in this
study are somewhat generic, as outdoor construction sites will often
have indoor locations, such as mobile offices, or locations with
reduced airflow, such as areas with a roof or ceiling and two or more
walls. Regardless, this study illustrates the comparable abundance of
evidence available to evaluate SARS-CoV-2 transmission in indoor
settings versus outdoor settings.
    Cevik et al. (August 1, 2021) reviewed studies on the transmission
dynamics of SARS-CoV-2 infections from large scale, contact-tracing
studies. The authors recommended that, based on the evidence that
outdoor transmission dynamics resulted in significantly fewer
infections than in indoor settings, public health entities should
greatly encourage use of outdoor settings. The researchers highlighted
a study by Nishiura et al. (April 16, 2020), who evaluated 110 cases in
Japan at the beginning of the pandemic and found that outdoor settings
reduced transmission risk by 18.7 times and reduced the risk of super-
spreader events by 32.5 times.
    Agricultural workplace settings have experienced significant SARS-
CoV-2 infections. However, transmission in these settings is difficult
to characterize because many jobs in this sector include both outdoor
and indoor activities. Miller et al. (April 30, 2021) evaluated an
outbreak among farmworkers in Washington State. The researchers found
that 28% of workers with predominantly indoor tasks where they were
unable to maintain physical distance were infected, compared to 6% of
workers who performed predominantly outdoors tasks in the orchards.
Conversely, a study on farmworkers in Monterey County, California found
a significant correlation between evidence of infection and individuals
who worked in the fields as opposed to indoor work (Mora et al.,
September 15, 2021). The paper noted that infections were predominant
in individuals who lived in crowded conditions, commuted together to
the fields, and spoke at home in indigenous languages, which is
important as written health messages are often not available in all
worker languages. These papers cannot identify where or when infections
occurred in order to discern causation. The associations observed may
indicate that SARS-CoV-2 infections may be more related to aspects
related to indoor exposures outside of the work activities (e.g.,
crowded living conditions) or potentially overlooked indoor aspects
connected to outdoor work (e.g., shared commuting).
    Several studies discussed below in more detail have evaluated
outdoors on-field transmission from infected participants during
football, soccer, and rugby matches. These events include repeated
close physical contact between players, without PPE or physical
distancing, over the course of fairly long events, with increased
exertion leading to greater respiratory effort and production of
respiratory droplets. These events also include opposing cohorts who
only interact during on-field activities. Therefore, these studies
provide some evidence for the low likelihood of outdoor transmission in
other workplace activities greatly impacted by the pandemic, such as in
construction.
    Mack et al. (January 29, 2021) detailed the National Football
League's complex program to assess and prevent transmission, which
included devices that recorded distance and duration of interactions
with others, for the purpose of improving identification of individuals
with high-risk exposures. Although 329 positive cases were identified
among roughly 11,400 players and staff, there were no reported cases of
on-field transmission by infected players. The results led the NFL to
focus more on reducing transmission in indoor settings, including
transportation.
    Egger et al. (March 18, 2021) reviewed three soccer matches
involving 18 players who had SARS-CoV-2; one match involved a team
where 44% of the players were infected. Video analysis was used to
determine the type of contact between players, such as contact to face
or hand slaps. None of the existing cases were associated with on-field
play and no secondary transmission from on-the-field contacts was
observed. Jones et al. (February 11, 2021), evaluated four rugby Super
League matches involving eight players who were found to be infected
with SARS-CoV-2. Using video footage and global positioning data, the
researchers were able to identify 28 players as high-risk contacts with
the infected players. These high-risk players together had as many as
32 tackles and were within two meters of infected players as often as
121 times during the four matches. Of the 28 players noted as high-risk
contacts, one became infected with SARS-CoV-2. However, researchers
determined that the transmission resulted from internal team outbreaks
and not from exposure on the field.
    OSHA acknowledges that the risk of transmission of SARS-CoV-2 in
outdoor settings is not zero, and that there may be some low risk to
workers performing general tasks exclusively in outdoor settings.
However, where studies have been able to differentiate between indoor
and outdoor exposures, they indicate that indoor exposures are the much
more significant drivers of SARS-CoV-2 infections. Therefore, the best
available evidence at this time does not provide OSHA with the
information needed to establish SARS-CoV-2 as a grave danger for
general work activities in outdoor settings (see Int'l Union, United
Auto., Aerospace, & Agr. Implement Workers of Am., UAW, 590 F. Supp. at
755-56, describing a ``grave danger'' as a risk that is more than
``significant''). Therefore, OSHA has excluded employees who work
exclusively outdoors from the scope of this ETS (see the Summary and
Explanation for Scope and Application, Section VI.B. of this preamble).
c. Employees in Healthcare
    Because OSHA issued a separate grave danger determination several
months ago for some healthcare workers, some explanation of how its
current finding applies to healthcare workers is necessary. In June
2021, OSHA issued its Healthcare ETS (86 FR 32376) after determining
that some healthcare workers faced a grave danger of infection from
SARS-CoV-2. This grave danger determination, along with the protections
of the Healthcare ETS, applied to healthcare and healthcare support
workers in settings where

people with suspected or confirmed cases of COVID-19 are treated, and
was based on the increased potential for transmission of the virus in
such settings (see 86 FR 32411-32412). These workers are currently
covered by the protections of the Healthcare ETS (29 CFR 1910.502).
OSHA does not have data to demonstrate that unvaccinated workers in
settings covered by the Healthcare ETS face a grave danger from SARS-
CoV-2 when the requirements of that standard are followed. However, if
the Healthcare ETS were no longer in effect, OSHA would consider the
workers who were covered by it, and who remain unvaccinated, to be at
grave danger for the reasons described in this ETS.
    OSHA's new finding of grave danger applies to healthcare and
healthcare support workers who are not covered by the Healthcare ETS,
to the extent they remain unvaccinated. In this ETS, as discussed in
this section, OSHA has made a broader determination of grave danger
that applies to most unvaccinated workers, regardless of industry.
OSHA's current finding of grave danger supporting this ETS does not
depend on whether a workplace is one where people with suspected or
confirmed COVID-19 are expected to be present. Therefore, the finding
of grave danger applies to unvaccinated workers in healthcare settings
that are not covered by 29 CFR 1910.502 to the same extent it applies
to unvaccinated workers in all other industry sectors.
d. Employees Who Were Previously Infected With SARS-CoV-2
    OSHA has carefully evaluated the effectiveness of previous SARS-
CoV-2 infections in providing protection against reinfection. This
section provides a detailed description of the current scientific
information in order to ascertain what the best available scientific
evidence on this topic indicates regarding the risk to individuals with
previous COVID-19 infections from exposure to SARS-CoV-2. While the
agency acknowledges that the science is evolving, OSHA finds that there
is insufficient evidence to allow the agency to consider infection-
acquired immunity to allay the grave danger of exposure to, and
reinfection from, SARS-CoV-2.
    To determine whether employees with infection-induced immunity from
SARS-CoV-2 (i.e., those who were infected with SARS-CoV-2 but have not
been vaccinated) face a grave danger, OSHA reviewed the scientific
evidence on the protective effects of vaccine-induced SARS-CoV-2
immunity versus infection-induced immunity. Individual immunity to any
infectious disease, including SARS-CoV-2, is achieved through a complex
response to exposure by the immune system. This response consists of
disease-specific antibody production guided and augmented by certain
types of immune cells, such as T and B cells, which work together to
neutralize or destroy the disease-causing agent. Immune responses to
viruses like SARS-CoV-2 can be measured in several ways. For instance,
blood serum can be taken and exposed to specific proteins found on the
SARS-CoV-2 virus, in order to measure the presence of antibodies in the
blood. Another antibody test, the neutralization test, measures the
ability of the antibodies present in a serum to neutralize infectivity
and prevent cells from being infected. T cell immunity can be measured
using techniques that target a specific biomolecule that is specific to
SARS-CoV-2.
    A considerable number of individuals who were previously infected
with SARS-CoV-2 do not appear to have acquired effective immunity to
the virus (Psichogiou et al., September 13, 2021; Wei et al., July 5,
2021; Cavanaugh et al., August 13, 2021). The level of protection
afforded by infection-induced immunity appears to depend on the
severity of individuals' infections. In a study from Greece,
immunogenicity was compared between healthcare workers who were
vaccinated with Pfizer-BioNTech and unvaccinated patients who acquired
a natural infection (Psichogiou et al., September 13, 2021). The
researchers found that the immune response in unvaccinated individuals
correlated to the severity of their disease. Fully vaccinated
healthcare workers had immune responses (measured as antibody levels
specific to SARS-CoV-2) that were 1.3 times greater than patients who
had critical cases of COVID-19 cases, 2.5 times greater than patients
who had moderate to severe cases, and 10.5 times greater than patients
who had asymptomatic/mild illnesses. Similarly, another study found
that 24.0% (1,742 of 7,256) of individuals who had a previous SARS-CoV-
2 infection were seronegative (i.e., did not produce antibodies in
response to the virus), suggesting that the previous infection provided
insufficient protection against future infection (Wei et al., July 5,
2021). Individuals who were seronegative were typically older, had
lower viral burdens when infected, and were more likely to be
asymptomatic. The authors posited that the immunity of those who were
seropositive (i.e., did produce antibodies in response to the virus)
would provide some measure of protection, but that these individuals
would benefit from a vaccination booster. This position appears to be
validated by a study that compared the reinfection rates of individuals
in Kentucky based on their post-recovery vaccination status (Cavanaugh
et al., August 13, 2021). Unvaccinated individuals with previous
infection were found to be 2.3 times more likely to be reinfected than
those who were vaccinated after their prior infection. These studies
demonstrate not only that those with milder infections may not be
protected against future infection, but that it is difficult to tell,
on an individual level, which individuals might have had prior
infections that conveyed protection equivalent to that provided by
vaccination.
    A number of other studies indicate that fully vaccinated
individuals may be better protected against future infection than those
with previous infections. A study in Massachusetts concluded that the
immunity conveyed from a previous SARS-CoV-2 infection was effectively
equivalent to the immunity of an uninfected individual who has had only
one dose of an mRNA vaccine (Naranbhai et al., October 13, 2021). The
authors found that fully vaccinated individuals have an immune response
(i.e., antibodies and neutralization) well above the levels observed in
unvaccinated, previously-infected individuals. German researchers found
that individuals who were fully vaccinated with Pfizer-BioNTech had a
significantly greater immune response (as measured by antibody levels)
than unvaccinated individuals who had infections, concluding that
vaccination would be needed for those unvaccinated individuals to have
similar protection against infection (Herzberg et al., June 13, 2021).
Similarly, a Dutch study observed that vaccination greatly improved the
immune response (as measured by antibodies and virus-specific T cells)
of individuals who had recovered from COVID-19 (Geers et al., May 25,
2021). Planas et al. (August 12, 2021) also noted that immune response
(as measured by neutralization) to the Alpha, Beta, and Delta
(B.1.617.2) variants in unvaccinated, previously-infected individuals
was considerably less than the immune response in individuals five
weeks after their second Pfizer-BioNTech dose. When unvaccinated,
previously-infected individuals were vaccinated, their immune response
(as measured by neutralization) increased by more than an order of
magnitude. Likewise, Wang

et al. (July 15, 2021) found that the immune response (as measured by
neutralization) of those with previous SARS-CoV-2 infection increased
by more than an order of magnitude against Alpha (B.1.1.7), Beta
(B.1.351), Iota (B.1.526), and Gamma (P.1) variants when they were
vaccinated. These studies show that infection-induced immunity may not
equal the protection afforded by vaccination and that vaccination
greatly improves the immune response of those who were previously
infected.
    The aforementioned studies indicate that immunity acquired through
infection appears to be less protective than vaccination. There are
also a number of epidemiological studies that provide some evidence
that infection-acquired immunity has the potential to provide a
significant level of protection against reinfection. As OSHA discusses
in greater detail below, these studies suffer from methodological
limitations that render them inconclusive about the level of immunity
conferred by infection, and therefore OSHA is unable to establish that
such immunity eliminates grave danger. This determination is based in
three parts.
    First, the epidemiological literature OSHA reviewed generally
suffers from selection bias to a degree that it serves as an unreliable
basis on which to reach a robust conclusion on whether previous
infection removes workers from grave danger. In general, the studies
described below do not account for people who had mild COVID-19
infections, leading to study findings regarding the level of protection
afforded by prior infection that are not generally applicable. Second,
the tests employed in the studies are being used in ways that they were
not originally designed to be employed. These tests are powerful tools,
but there are limitations to their use in determining if a specific
individual is, in fact, protected from the grave danger of SARS-CoV-2.
Particularly problematic is the lack of established thresholds to
determine full protection from reinfection or even a standardized
methodology to determine infection severity or immune response. Thus,
while these studies broadly establish some increase in protectiveness
against SARS-CoV-2 among the studied populations, they as yet are
unable to provide a reasonable degree of certainty on whether the
degree of protection afforded any particular individual from their
prior infection is sufficient to eliminate the grave danger from
reinfection (see Milne, et al., October 21, 2021.) Third, while the
research methodology itself creates difficulties in the context of
OSHA's grave danger inquiry, the implications of trying to apply
investigative research methodology to clinical practice are even more
challenging. The need for the development of standardized methods and
criteria for establishing sufficient immunity preclude the application
of the studies' findings to robust and reliable clinical practice.
These three rationales for OSHA's finding are described in more detail
below.
    Several epidemiological studies used previous RT-PCR positive cases
to define previous infections (Hansen et al., March 27, 2021; Pilz et
al., February 11, 2021; Vitale et al., May 28, 2021; Pouwels et al.,
October 14, 2021; Braeye et al., September 15, 2021; Hall et al., April
17, 2021). RT-PCR tests, particularly in the beginning of the pandemic,
were given high priority to discern who seeking medical care was, in
fact, infected. For instance, the progression of testing from medical
needs to more of a community perspective is illustrated in Denmark
(Vrangbaek et al., April 29, 2021). Denmark, considered one of the gold
standard countries for its comprehensive testing program, missed five
infections for every one it identified in the spring of 2020 (Espenhaim
et al., August 22, 2021). Hansen et al. (March 27, 2021) depended
greatly on these first surge infection definitions to determine that
survivors had protection of 80.5% effectiveness during the second surge
in Denmark from September through December, 2020. By only noting RT-PCR
positives from the spring when testing was limited and highly focused
on health care needs, it seems apparent that the study excluded many
less severe cases (which are less likely to result in an effective
immune response against reinfection), leading to results that may
suggest greater protection is afforded by infection than in actuality.
Even by December of 2020, it appears Denmark's gold standard
comprehensive testing approach was only able to capture roughly half of
all infections. Similar systemic undercounts have also been determined
to be true in the United States where approximately three out of four
infections have never been reported (CDC, July 27, 2021b).
    It is important to recognize that RT-PCR testing was not
implemented to find every infection, but was used instead to assist in
determining when medical and community interventions were necessary.
Infections without symptoms or with mild symptoms likely would not
require medical intervention and, therefore, would likely not be
identified via testing. The absence of this population that is more
vulnerable to reinfection, in these studies, undercuts their usefulness
in OSHA's grave danger analysis, because they may overestimate the
protectiveness of immunity acquired through infection.
    Several other studies in regions less known for their sampling
approach than Denmark also were heavily dependent on early, limited
pandemic RT-PCR testing. An Austrian study found a roughly ten-fold
decrease in reinfection in survivors of reported infections from
February to April 30, 2020 in comparison with the general public (Pilz
et al., February 11, 2021). The authors noted that ``infections in the
first wave are likely to have been far more common than the documented
ones'' and referred to their results as a ``rough estimate.''
Researchers at the Cleveland Clinic also found a reduced rate of
reinfection in those who had a reported previous infection compared
with those with no prior infection (13.8% infection rate for those
previously uninfected and 4.9% infection rate for those previously
infected), but noted that testing was limited in that the ``Cleveland
Clinic did not test asymptomatic patients unless they were admitted to
hospital or undergoing a procedure/surgery'' (Sheehan et al., March 15,
2021). These criteria for testing create uncertainty in determining the
level of effectiveness previous infection provides against SARS-CoV-2
because many individuals with asymptomatic infections would not have
been tested. Similar issues are also found in studies on populations in
Italy, Belgium, and the UK (Vitale et al., May 28, 2021; Braeye et al.,
September 15, 2021; Pouwels et al., October 14, 2021).
    To avoid the well-known problems with RT-PCRs defining previous
infection, other studies have defined previous infection as testing
positive for antibodies specific for SARS-CoV-2 (Lumley et al.,
February 11, 2021; Abu-Raddad et al., April 28, 2021; Hall et al.,
April 17, 2021). As noted above, previous infection does not
necessarily result in a seropositive outcome; one study indicated that
nearly a quarter (24%) of those infected with SARS-CoV-2 subsequently
showed no sign of an immune response in SARS-CoV-2-specific antibody
testing (Wei et al., July 5, 2021). Therefore, studies only considering
seropositive individuals are in essence studying only the individuals
most likely to have protection from reinfection. Lumley et al.
(February 11, 2021) found that those having a seropositive response had
almost an order of magnitude fewer infections (e.g., 0.11 adjusted
incidence rate ratio). Likewise, Abu-Raddad et al. (April 28,

2021) found that seropositive individuals were reinfected less (0.7%)
during their study period in comparison to seronegative individuals
(3.09%). In addition to the bias associated with using antibodies to
determine previous infection, the authors also noted that there may
have been issues with being able to document cases with mild or no
symptoms.
    Hall et al. (April 17, 2021) cast a wider net by defining previous
infection to include both positive RT-PCR tests and seropositivity. The
researchers found that those who were considered previously infected
had an 84% lower risk of infection compared to those who were
unvaccinated with no record of infection. While the study does attempt
to capture as many previously-infected individuals as possible, this
does not actually address the weaknesses of each method. Those with
less severe infections were less likely to have sought out or been able
to get an RT-PCR test during the first surge, which is when an
overwhelming number of the previous infections were recorded in this
study (March through May, 2020). Additionally, the less severe
infections that are most likely underrepresented in the study appear to
be the ones that are less likely to produce seropositivity. Shenai et
al. (September 21, 2021) pooled several studies with the above issues
and concluded that immunity acquired through a previous infection from
SARS-CoV-2 may be as protective as, or more protective than, the
immunity afforded by vaccination to an individual without previous
infection. However, authors of several of those underlying studies used
in the analysis noted that their studies were limited by not having the
capability to fully account for asymptomatic infections (the
aforementioned Lumley et al., July 3, 2021; Gazit et al., August 25,
2021; Shrestha et al., June 19, 2021). As noted earlier, infection
severity appears to be correlated with the robustness of immunity
acquired through that infection, so the failure to account for
asymptomatic infections may mean that this finding is related to the
protection afforded by more severe disease. While pooled analyses can
be utilized to make powerful observations, those observations are
highly dependent upon the underlying studies not sharing the same
methodological weakness which, in this case, was the studies' exclusion
of asymptomatic infections.
    Moreover, while the evidence suggests that severe infection may
provide significant protection against reinfection in some cases (Milne
et al., October 21, 2021), the level of protection cannot be determined
on an individual basis. The studies discussed above are based on tests
that show only whether a person was or was not infected and provide no
information about the severity of the infection. Because the studies
are likely biased towards those who had a relatively serious infection,
their findings cannot be generalized to all individuals with prior
infections.
    RT-PCR and antibody testing are powerful tools with many clinical
and research applications. However, the application of these tools
cannot determine what degree of protection a particular individual has
against SARS-CoV-2 without a great deal of additional study concerning
thresholds establishing individual immunity. Therefore, these tools are
not yet able to assist OSHA in making more nuanced findings about which
workers who had COVID-19 previously are at grave danger. There is no
established threshold to determine full protection from reinfection or
a standardized methodology to determine infection severity or immune
response. Studies use Ct threshold to approximate viral loads and infer
disease severity, but that metric depends on many variables (e.g. time
of collection during infection, quality of collection, handling of
sample, specifics of the test protocol and materials, precision in
performing the protocol) that are often of far less importance when it
is used as a crude diagnostic to determine the presence of an
infection. In other words, it is reasonable to say that the lower the
Ct count, the greater the likelihood that an individual is at a lower
reinfection risk; however, the Ct count is greatly dependent on the RT-
PCR test used, and how different laboratories may run that test, which
cannot be discerned. Similarly, research needs to be done to better
identify the minimum protective threshold of anti-SARS-CoV-2 serum
neutralizing antibodies (Milne et al., October 21, 2021). Thus, these
studies currently do not allow OSHA to determine, with a reasonable
degree of certainty, how much protection employees with prior
infections have against reinfection.
    Furthermore, while the research methodology itself raises
challenges in making the grave danger determination, the implications
of trying to apply investigative research methodology to clinical
practice are even more difficult. The lack of standardized methods and
standardized measures for immunity preclude their application to robust
and reliable clinical practice. One major drawback discussed above is
that, in contrast to vaccine studies where researchers know who was
vaccinated with a standardized dosing regime, scientific inquiries
likely will not be able to identify most individuals who were infected,
the degree of disease experienced for those with a confirmed infection,
and the immunity against reinfection. As of October 18, 2021, several
RT-PCR assays have been authorized without standardization or
assessment with respect to measuring disease severity (FDA, October 18,
2021). As noted above, the use of the Ct threshold to approximate viral
loads and infer disease severity is unreliable. As the FDA notes, the
same is true about antibody tests, which are considered to be poor
indicators for individuals to use to determine whether they are
protected from reinfection (FDA, May 19, 2021). There are many
different SARS-CoV-2-specific antibody tests that focus on different
specificity. Not only are the outcomes of these tests not directly
comparable to each other, but the specificity of these tests is not
related to any notion of protection against reinfection. It can be
reasonably said that a greater antibody response means a greater
likelihood of protection against infection, but, again, the science is
not clear what those thresholds are and whether a threshold would be
comparable between laboratories. At this point in time, even if OSHA
determined that some individuals with prior infections are not at grave
danger from exposure to SARS-CoV-2, there is no agreement on what
indicators of infection might be sufficient to confer this level of
immunity or how a healthcare provider or employer could document that a
certain level of immunity had been achieved.
    Based on the best available evidence described above, OSHA
concludes that while some individuals who were infected with SARS-CoV-2
may have significant protection from subsequent infections, the level
of protection afforded by infection may be significantly impacted by
the severity of the infection and some previously infected individuals
may have no future protection at all. In addition, given the
limitations of the studies described above, there is considerable
uncertainty as to whether any given individual is adequately protected
against reinfection. Furthermore, the level of protection, if any,
provided by a given person's SARS-CoV-2 infection cannot be ascertained
based on currently-available testing methods. Therefore, OSHA finds
that the requirements of this ETS are necessary to protect unvaccinated
individuals who had prior SARS-CoV-2 infections from the grave danger
from exposure to SARS-CoV-2.

    OSHA recognizes that its finding regarding infection-induced
immunity is being made in an area of inquiry that is currently on the
``frontiers of scientific knowledge'' (Indus. Union Dep't, AFL-CIO v.
Am. Petroleum Inst., 448 U.S. 607, 656 (1980)). For these reasons, OSHA
finds that those who have previously been infected with SARS-CoV-2 and
are not yet fully vaccinated are at grave danger from SARS-CoV-2
exposure and that it is necessary to protect these workers via
vaccination, or testing and the use of face coverings, under this
standard. OSHA will continue to follow developments on this issue,
however, and make appropriate adjustments to this ETS if the evidence
warrants.
VI. Conclusion.
    OSHA finds that many employees in the U.S. who are not fully
vaccinated against COVID-19 face a grave danger from exposure to SARS-
CoV-2 in the workplace. OSHA's determination is based on the severe
health consequences of exposure to the virus, including death; powerful
lines of evidence demonstrating the transmissibility of the virus in
the workplace; and the prevalence of infections in employee
populations.
    With respect to the grave health consequences of exposure to SARS-
CoV-2, OSHA has found that regardless of where and how exposure occurs,
COVID-19 can result in death. Even for those who survive a SARS-CoV-2
infection, the virus can cause serious, long-lasting, and potentially
permanent health effects. Serious cases of COVID-19 require
hospitalization and dramatic medical interventions, and might leave
employees with permanent and disabling health effects. Both death and
serious cases of COVID-19 requiring hospitalization provide independent
bases for OSHA's finding of grave danger. The evidence is clear that
the safe and effective vaccines authorized and/or approved for use in
the United States greatly reduce the likelihood of these severe
outcomes.
    The best available evidence on the science of transmission of the
virus makes clear that SARS-CoV-2 is transmissible from person to
person in shared workplace settings. The likelihood of transmission can
be exacerbated by common characteristics of many workplaces, including
working indoors, working with others for extended periods of time, poor
ventilation, and close contact with potentially infectious individuals.
The likelihood of transmission in the workplace is also exacerbated by
the presence of unvaccinated workers, who are more likely than those
who are vaccinated to be infected and transmit the virus to others.
Every workplace SARS-CoV-2 exposure or transmission has the potential
to cause severe illness or even death, particularly in unvaccinated
workers. Taken together, the severe health consequences of COVID-19 and
the evidence of its transmission in environments characteristic of the
workplaces covered by this ETS demonstrate that exposure to SARS-CoV-2
represents a grave danger to unvaccinated employees in many workplaces
throughout the country.
    The existence of a grave danger to employees from SARS-CoV-2 is
further supported by the toll the pandemic has already taken on the
nation as a whole and the number of workers who remain unvaccinated.
Although OSHA cannot state with precision the total number of workers
in our nation who have contracted COVID-19 at work and became sick or
died, COVID-19 has killed 723,205 people in the United States as of
October 18, 2021 (CDC, October 18, 2021--Cumulative US Deaths). That
death toll includes 131,478 people who were 18 to 64 years old, prime
working age (CDC, October 18, 2021--Demographic Trends, Deaths by Age
Group). OSHA estimates that there are over 26 million workers subject
to the rule who remain unvaccinated at present and therefore are in
grave danger. As a result of this ETS, the agency estimates that 72% of
them will be vaccinated (see OSHA, October 2021c).
    Current mortality data shows that unvaccinated people of working
age have a 1 in 202 chance of dying when they contract COVID-19 (CDC,
October 18, 2021--Demographic Trends, Cases by Age Group; Demographic
Trends, Deaths by Age Group). As of October 18, 2021, close to 45
million people in the United States have been reported to have
infections, and thousands of new cases were being identified daily
(CDC, October 18, 2021--Daily Cases).One in 14 reported cases of COVID-
19 in people ages 18 to 64 becomes severe and requires hospitalization
(CDC, October 18, 2021--Demographic Trends, Cases by Age; Total
Hospitalizations, by Age). Moreover, public health officials agree that
these numbers fail to show the full extent of the deaths and illnesses
from this disease, and racial and ethnic minority groups are
disproportionately represented among COVID-19 cases, hospitalizations,
and deaths (CDC, December 10, 2020; CDC, May 26, 2021; Escobar et al.,
February 9, 2021; Gross et al., October 2020; McLaren, June 2020; CDC,
October 6, 2021). Given this context, OSHA is confident in its finding
that exposure to SARS-CoV-2 poses a grave danger to the employees
covered by this ETS.
    The above analysis fully satisfies the OSH Act's requirements for
finding a grave danger. Although OSHA usually performs a quantitative
risk assessment based on extrapolations among exposure levels before
promulgating a health standard under section 6(b)(5) of the OSH Act (29
U.S.C. 655(b)(5)), that type of analysis is not necessary in this
situation. OSHA has most often invoked section 6(b)(5) authority to
regulate exposures to chemical hazards involving much smaller
populations, many fewer cases, extrapolations from animal evidence,
long-term exposure, and delayed effects. In those situations,
mathematical modelling is necessary to evaluate the extent of the risk
at different exposure levels. The gravity of the danger presented by a
disease with acute effects like COVID-19, on the other hand, is made
obvious by a straightforward count of deaths and illnesses caused by
the disease, which reach sums not seen in at least a century. The
evidence compiled above amply supports OSHA's finding that SARS-CoV-2
presents a grave danger in American workplaces. In the context of
ordinary 6(b) rulemaking, the Supreme Court has said that the OSH Act
is not a ``mathematical straitjacket,'' nor does it require the agency
to support its findings ``with anything approaching scientific
certainty,'' particularly when operating on the ``frontiers of
scientific knowledge'' (Indus. Union Dep't, AFL-CIO v. Am. Petroleum
Inst., 448 U.S. 607, 655-56 (1980)). This is true a fortiori in the
current national crisis, where OSHA must act to ensure employees are
adequately protected from the hazard presented by the COVID-19 pandemic
(see 29 U.S.C 655(c)(1)).The grave danger from SARS-CoV-2 represents
the biggest threat to employees in OSHA's more than 50-year history.
The threat applies to employees in all sectors covered by OSHA,
including general industry, construction, maritime, agriculture, and
healthcare. Having made the determination of grave danger, as well as
the determination that an ETS is necessary to protect employees from
exposure to SARS-CoV-2 (see Need for the ETS, Section III.B. of this
preamble), OSHA is required to issue this standard to protect employees
from getting sick or dying from COVID-19 acquired at work (see 29
U.S.C. 655(c)(1)).

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B. Need for the ETS

    This ETS is necessary to protect unvaccinated workers from the risk
of contracting COVID-19, including its more contagious variants, such
as the B.1.617.2 (Delta), at work. The rule protects workers through
the most effective and efficient workplace control available:
Vaccination. Additionally, this ETS is necessary to protect workers who
remain unvaccinated through required regular testing, use of face
coverings, and removal of infected employees from the workplace.
I. Events Leading to the ETS
    This section describes the evolution of OSHA's actions to protect
employees from the grave danger posed by COVID-19 and the agency's
reasons for issuing this ETS at this time.
a. OSHA's 2020 Actions Regarding COVID-19
    Beginning in early 2020, OSHA began to monitor the growing cases of
the SARS-CoV-2 virus that were occurring around the country. Because
scientific information about the disease, its potential duration, and
ways to mitigate it were undeveloped, OSHA decided to monitor the
situation. As noted below, OSHA subsequently issued numerous guidance
documents advising interested employers of steps they could take to
mitigate the hazard arising from the virus.
    Also beginning in early 2020, OSHA received numerous petitions and
supporting letters from members of Congress, unions, advocacy groups,
and one group of large employers urging the agency to take immediate
action by issuing an ETS to protect employees from exposure to the
virus that causes COVID-19 (Scott and Adams, January 30, 2020; NNU,
March 4, 2020; AFL-CIO, March 6, 2020; Menendez et al., March 9, 2020;
Wellington, March 12, 2020; DeVito, March 12, 2020; Carome, March 13,
2020; SMART, March 30, 2020; Blumenthal et al., April 8, 2020; Murray
et al., April 29, 2020; Luong, April 30, 2020; Novoa, June 24, 2020;
Solt, April 28, 2020; Castro et al., April 29, 2020; Talbott and Adely,
May 4, 2020; Public Citizen, March 13, 2020;

LULAC, March 31, 2020; Meuser, May 1, 2020; Raskin, April 29, 2020;
Cartwright et al., May 7, 2020; Frosh et al., May 12, 2020; Pellerin,
March 19, 2020; Yborra, March 19, 2020; Owen, March 19, 2020; Brown et
al., April 30, 2020; Price et al., May 1, 2020; ORCHSE, October 9,
2020). These petitions and supporting letters argued that many
employees had been infected because of workplace exposures to the virus
that causes COVID-19, and that immediate, legally enforceable action is
necessary for protection. OSHA quickly began issuing detailed guidance
documents and alerts beginning in March 2020 that helped employers to
determine employee risk levels of COVID-19 exposure and made
recommendations for appropriate controls. As explained in detail in
Section IV. of the Healthcare ETS, 86 FR 32376, 32412-13 (June 21,
2021) and hereby included in the record for this ETS,\16\ at the time,
OSHA leadership believed that implementing a combination of enforcement
tools, including guidance, existing OSHA standards, and the General
Duty Clause, would provide the necessary protection for workers. OSHA
also expressed concern that an ETS might unintentionally enshrine
requirements that are subsequently proven ineffective in reducing
transmission.
---------------------------------------------------------------------------

    \16\ This adoption includes the citations in the referenced
section of the Healthcare ETS, which are also included in the docket
for this ETS.
---------------------------------------------------------------------------

    When it decided not to issue an ETS in the spring of 2020, OSHA
determined that the agency could provide sufficient employee protection
against COVID-19 through enforcing existing workplace standards and the
General Duty Clause of the OSH Act, coupled with issuing industry-
specific, non-mandatory guidance. However, in doing so OSHA indicated
that its conclusion that an ETS was not necessary was specific to that
time, and that the agency would continue to monitor the situation and
take additional steps as appropriate (see, e.g., OSHA, March 18, 2020
Letter to Congressman Scott (stating ``[W]e currently see no additional
benefit from an ETS in the current circumstances relating to COVID-19.
OSHA is continuing to monitor this quickly evolving situation and will
take the appropriate steps to protect workers from COVID-19 in
coordination with the overall U.S. government response effort.''
(emphasis supplied); DOL May 29, 2020 at 20 (stating ``OSHA has
determined this steep threshold [of necessity] is not met here, at
least not at this time.'' (emphasis supplied))).
    In addition to the various petitions for rulemaking that were
submitted to OSHA, the AFL-CIO filed a petition for a writ of mandamus
with the U.S. Court of Appeals for the D.C. Circuit, requesting that
the court compel OSHA to issue an ETS. (AFL-CIO, May 18, 2020). In its
administrative decision and filing in that case, OSHA explained that
the determination not to issue an ETS was based on the conditions and
information available to the agency at that time and was subject to
change as additional information indicated the need for an ETS. On June
11, 2020, the U.S. Court of Appeals for the D.C. Circuit issued a one
paragraph per curiam order denying the AFL-CIO's petition to require
OSHA to issue an ETS. To be clear, nothing in OSHA's prior position or
the D.C. Circuit's decision in In re Am. Fed'n of Labor & Cong. of
Indus. Orgs., No. 20-1158, 2020 WL 3125324 (D.C. Cir. June 11, 2020);
rehearing en banc denied (July 28, 2020) precludes OSHA's decision to
promulgate an ETS now. To the contrary, at an early phase of the
pandemic, when vaccines were not yet available and when it was not yet
known how extensive the impact would be on illness and death, the court
decided not to second-guess OSHA's decision to hold off on regulation
in order to see if its nonregulatory enforcement tools could be used to
provide adequate protection against the virus. ``OSHA's decision not to
issue an ETS is entitled to considerable deference,'' the court
explained, noting ``the unprecedented nature of the COVID-19 pandemic''
and concluding merely that ``OSHA reasonably determined that an ETS is
not necessary at this time.'' (Id., with emphasis added).
    Employers do not have a reliance interest in OSHA's prior decision
not to issue an ETS on May 29, 2020, which did not alter the status quo
or require employers to change their behavior. See Dep't of Homeland
Security v. Regents of the Univ. of California, 140 S. Ct. 1891, 1913-
14 (2020). As OSHA indicated when it made the decision, the
determination was based on the conditions and information available to
the agency at that time and was subject to change as additional
information indicated the need for an ETS. In light of the agency's
express qualifications and the surrounding context, any employer
reliance would have been unjustified and cannot outweigh the
countervailing urgent need to protect workers covered by this ETS from
the grave danger posed by COVID-19.
b. OSHA's Decision To Promulgate a Healthcare ETS
    OSHA subsequently issued the Healthcare ETS to protect healthcare
workers. 86 FR 32376. (June 21, 2021), codified at 29 CFR 1910.502.
Looking back on a year of experience, OSHA found that its enforcement
efforts had encountered significant obstacles, demonstrating that
existing standards, regulations, and the General Duty Clause were
inadequate to address the grave danger faced by healthcare employees.
86 FR 32415. In promulgating that ETS, OSHA recognized that ``the
impact of [COVID-19] has been borne disproportionately by the
healthcare and healthcare support workers tasked with caring for those
infected by this disease.'' 86 FR 32377. Furthermore, states and
localities had taken increasingly divergent approaches to workplace
protections against COVID-19, making it clear that a federal standard
was needed to ensure sufficient protection in all states. 86 FR 32377.
Therefore, OSHA focused on the unique situation experienced by
healthcare industry workers as the frontline caregivers and support
workers for those suffering from COVID-19. See 86 FR 32376, 32411-12.
    The Healthcare ETS requires employers to institute a suite of
engineering controls, administrative controls, work practices, and
personal protective equipment to combat the COVID-19 hazard. In the
Preamble to the Healthcare ETS, OSHA observed that the development of
safe and highly effective vaccines is a critical milestone in the
nation's response to COVID-19, and that fully vaccinated persons have a
greatly reduced risk of death, hospitalization and other health
consequences. 86 FR 32396. The Healthcare ETS therefore includes
provisions intended to encourage employees to become vaccinated,
including a requirement for employers to provide reasonable paid leave
for vaccination and recovery from any side effects. 86 FR 32415, 29 CFR
1910.502(m).
    In the Healthcare ETS OSHA found that employees who work in covered
healthcare workplaces are exposed to grave danger. 86 FR 32411. The
agency also stated that in light of the effectiveness of vaccines,
there was ``insufficient evidence in the record to support a grave
danger finding for non-healthcare workplaces where all employees are
vaccinated.'' 86 FR 32396 (emphasis supplied). OSHA made no finding at
that time regarding unvaccinated workers in non-healthcare workplaces.

    No employer challenged the Healthcare ETS in court. The United Food
and Commercial Workers Union (UFCW) together with the AFL-CIO filed a
petition for review asserting that the rule should have gone further
and included more industries in its scope (UFCW and AFL-CIO, June 24,
2021). That case is being held in abeyance pending the issuance of this
ETS.
c. Subsequent Developments
    The preamble to the Healthcare ETS notes that new COVID-19 variants
might emerge that are more transmissible and cause more severe illness,
but does not specifically mention the Delta Variant. See 86 FR 32384.
Since publication of the Healthcare ETS, the Delta Variant has become
the dominant form of the virus in the United States, causing large
spikes in transmission, and surges of hospitalizations, and deaths,
overwhelmingly among the unvaccinated (CDC, August 26, 2021; CDC,
October 18, 2021--Variant Proportions, July Through October, 2021). As
discussed in more detail in Grave Danger (Section III.A. of this
preamble), the Delta Variant is at least twice as contagious as
previous COVID-19 variants, and research suggests that it also causes
more severe illness in the unvaccinated population (CDC, August 26,
2021). More infections mean more potential for exposures, including in
workplaces (see Grave Danger, Section III.A. of this preamble, for
further discussion on workplace outbreaks, clusters, and the general
impact of transmission in the workplace.). More infections also mean
more opportunities for the virus to undergo mutations to its genetic
code, resulting in genetic variants with the potential to infect or re-
infect people.
    Some variability in infection rates in a pandemic is to be
expected. While the curves of new infections and deaths can bend down
after peaks, they often reverse course only to reach additional peaks
in the future (Moore et al., April 30, 2020). Last year experts
expressed concern that one or more subsequent waves of COVID-19 were
possible in 2021 (Moore et al., April 30, 2020), especially with new
variants of COVID-19 in circulation (Doughton, February 9, 2021). That
potential tragically became a reality with the spread of the Delta
Variant.
    In June 2021, when the Healthcare ETS was published, COVID-19
transmission rates in the United States were at a low point, with the
7-day moving average of reported cases to be about 12,000. (CDC, August
26, 2021) However, by the end of July, the 7-day moving average reached
over 60,000 as the Delta Variant spread across the country. (CDC,
August 26, 2021). The 7-day moving average of reported cases at the
beginning of September, 2021 exceeded 161,000 (CDC, October 18, 2021--
Daily Cases). The most recent 7-day moving average of reported cases,
while lower than the peak in late August and early September, is still
over 85,000. (CDC, October 18, 2021--Daily Cases). These rates are also
far higher than the rate when OSHA first declined to issue an ETS.
(CDC, August 27, 2020 (20,401 confirmed cases per day on May 29,
2020)). The jump in infections has resulted in increased
hospitalizations and deaths for unvaccinated workers, as discussed in
detail in Grave Danger (Section III.A. of this preamble). While the
most current data reflect a decline in new cases from the peak, the
level of new cases remains high. CDC data shows that, as of October 18,
2021, approximately 85% of U.S. counties were experiencing ``high''
rates of community transmission, and another 10% were experiencing
``substantial'' community transmission (CDC, October 18, 2021--Daily
Cases). Although the number of new detected cases is currently
declining nationwide (see CDC, October 18, 2021--Community Transmission
Rates), the agency cannot assume based on past experience that
nationwide case levels will not increase again. Indeed, many northern
states are currently experiencing increases in their rate of new cases
(see CDC, October 18, 2021--Cases, Deaths, and Laboratory Testing
(NAATS) by State; Slotnik, October 18, 2021), including Vermont, which
set a new record for new COVID-19 cases in mid-October 2021 (Murray,
October 18, 2021). Unless vaccination rates increase, the experience of
northern states during this fall could presage a greater resurgence in
cases this winter as colder weather drives more individuals indoors
(see Firozi and Dupree, October 18, 2021).
    While it is important to recognize that the Delta Variant has
caused a spike in hospitalization and death in the United States, the
SARS-CoV-2 virus, and not just a particular variant of that virus, is
the hazard that workers face (see Grave Danger, Section III.A. of this
preamble). Like any virus, SARS-CoV-2 has the ability to mutate over
time and produce variants that may be more or less severe. Indeed, the
World Health Organization and the CDC both track new variants that have
continued to arise, such as the Lamda and Mu Variants (WHO, October 12,
2021; CDC, October 4, 2021). At this time, the CDC is tracking 11
different variants of COVID-19 (CDC, October 4, 2021). The World Health
Organization has classified the Lambda and Mu variants as ``variants of
interest,'' meaning that they have genetic changes that affect
transmissibility, disease severity, immune escape, diagnostic or
therapeutic escape; and have been identified to cause significant
community transmission or multiple COVID-19 clusters, in multiple
countries with increasing relative prevalence alongside increasing
number of cases over time, or other apparent epidemiological impacts to
suggest an emerging risk to global public health (WHO, October 12,
2021). Medical experts have also explained that vaccination reduces the
opportunities for the virus to continue to mutate by reducing
transmission and length of infection. And, there is no indication that
future variants of COVID-19 will not be equally or even more dangerous
than Delta without a higher rate of vaccination (Bollinger and Ray,
July 23, 2021).
    Meanwhile, evidence on the power of vaccines to safely protect
individuals from infection and especially from serious disease has
continued to accumulate. (CDC, May 21, 2021). For example, as explained
in more detail in Grave Danger (Section III.A. of this preamble),
multiple studies have demonstrated that vaccines are highly effective
at reducing instances of hospitalization and death. In September the
CDC compiled data from various studies that demonstrated overall
authorized vaccines reduced death and severe case rates by 91 and 92%
respectively in the population studied between April and July (Scobie
et al., September 17, 2021, Table 1.). Additionally, the FDA granted
approval to the Pfizer-BioNTech COVID-19 Vaccine for individuals 16
years of age and older on August 23, 2021 (FDA, August 23, 2021). In
announcing the decision, the FDA Commissioner explained that ``[w]hile
this and other vaccines have met the FDA's rigorous, scientific
standards for emergency use authorization, as the first FDA-approved
COVID-19 vaccine, the public can be very confident that this vaccine
meets the high standards for safety, effectiveness, and manufacturing
quality the FDA requires of an approved product.'' (FDA, August 23,
2021.)
    Despite this important milestone, and the demonstrated
effectiveness of the approved and authorized vaccines available to the
public, millions of employees remain unvaccinated, approximately 39% of
workers who are covered by this ETS (See Economic Analysis, Section
IV.B. of this ETS). The rate of vaccination in the United States

has slowed significantly from its peak in April, when the daily number
of vaccination doses administered exceeded three million at one point.
In recent months, daily vaccination rates have hovered around one
million doses administered, or lower (CDC, October 18, 2021--Daily
Vaccination Rate). The shortfall in vaccination leaves the nation's
working population vulnerable to sickness, hospitalization and death,
whether today under the Delta Variant, or under future variants that
may arise (CDC, October 18, 2021--Daily Vaccination Rate); see also
Grave Danger (Section III.A. of this preamble).
    Moreover, in recent months, an increasing number of states have
promulgated Executive Orders or statutes that prohibit workplace
vaccination policies that require vaccination or proof of vaccination
status, thus attempting to prevent employers from implementing the most
efficient and effective method for protecting workers from the hazard
of COVID-19 (see, e.g., Texas Executive Order GA-40, October 11, 2021;
Montana H.B. 702, July 1, 2021; Arkansas S.B. 739, October 4, 2021 and
Arkansas H.B. 1977, October 1, 2021; AZ Executive Order 2021-18, August
16, 2021). While some States' bans have focused on preventing local
governments from requiring their public employees to be vaccinated or
show proof of vaccination, the Texas, Montana, and Arkansas
requirements apply to private employers as well. Other states have
banned local ordinances that require employers to ensure that customers
who enter their premises wear masks, thus endangering the employees who
work there, particularly those who are unvaccinated (see, e.g., Florida
Executive Order 21-102, May 3, 2021; Texas Executive Order GA-34, March
2, 2021).
    In short, at the present time, workers are becoming sick and dying
unnecessarily as a result of occupational exposures, when there is a
simple and effective measure, vaccination, that can largely prevent
those deaths and illnesses (see Grave Danger, Section III.A. of this
preamble). Congress charged OSHA with responsibility for issuing
emergency standards when they are necessary to protect employees from
grave danger. 29 U.S.C. 655(c). In light of the current situation, OSHA
is issuing this emergency rule.

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filed with the D.C. Circuit on June 24, 2021.'' (UFCW and AFL-CIO,
June 24, 2021)
Wellington M. (2020, March 12). ``Grant OSHA emergency standard for
COVID-19 to protect front-line workers'' (Wellington, March 12,
2020)
World Health Organization (WHO). (2021, October 12). Tracking SARS-
CoV-2 variants. https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/. (WHO, October 12, 2021)
Yborra G. (2020, March 19). ``Grant OSHA emergency standard to
protect frontline workers from COVID-19.'' (Yborra, March 19, 2020)
II. This ETS Is Necessary To Protect Unvaccinated Employees From Grave
Danger
    As explained at length in the preceding section (Grave Danger,
Section III.A. of this preamble), OSHA has determined that most
unvaccinated workers across the U.S. economy are facing a grave danger
posed by the COVID-19 hazard.\17\ This new hazard has taken the lives
of more than 725,000 people--many of them workers--in the United States
since it was first detected in this country in early 2020. As the
federal agency tasked with protecting the safety and health of workers
in the United States, OSHA is required to act when it finds that
workers are exposed to a grave danger. 29 U.S.C. 655(c)(1). OSHA now
finds that this emergency temporary standard is necessary to protect
employees who are unvaccinated. Asbestos Info. Ass'n, 727 F.2d at 423
(``failure to act does not conclusively establish that a situation is
not an emergency . . . [when there is a grave danger to workers,] to
hold that because OSHA did not act previously it cannot do so now only
compounds the consequences of the Agency's failure to act.''). As
explained in detail below, OSHA has determined that vaccination is the
most effective control for abating the grave danger that unvaccinated
employees face from the COVID-19 hazard. And, for workers who are not
vaccinated, the use of testing, face coverings, and removal from the
workplace, while not as effective as vaccination, is still effective
and necessary.
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    \17\ As explained in the Grave Danger section, this ETS focuses
on protecting unvaccinated workers from the grave danger that COVID-
19 poses in the workplace. OSHA did not include fully vaccinated
workers in its finding of grave danger because such workers are
generally much better protected from the effects of COVID-19, and,
in particular, the most severe effects, than workers who are
unvaccinated. OSHA's action in adopting this ETS for unvaccinated
workers does not mean that vaccinated workers do not face a
significant risk from COVID-19, or that the OSH Act's general duty
clause poses no obligation on employers to protect their vaccinated
workers from COVID-19. Indeed, symptomatic infections can occur in
fully vaccinated people, and COVID-19 therefore poses at least some
risk to vaccinated workers. OSHA has requested comment on the risks
faced by vaccinated workers from COVID-19, and what additional
measures, if any, should be taken to protect both vaccinated and
unvaccinated workers (see Request for Comments, Section I.B. of this
preamble).
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    OSHA has determined that the best method for addressing the grave
danger that COVID-19 poses to unvaccinated workers is to strongly
encourage the use of the single most effective and efficient protection
available: Vaccination. OSHA

has long recognized the importance of vaccinating workers against
preventable illnesses to which they may be exposed on the job. See 56
FR 64004, 64152 (Dec. 6, 1991) (discussing requirement in Bloodborne
Pathogens standard for employer to make hepatitis B vaccine available
to any employees with occupational exposure to blood and other
potentially infectious materials). As explained in Grave Danger
(Section III.A. of this preamble), COVID-19 vaccines do not completely
eliminate the potential for infection, but significantly reduce the
likelihood of infection, and in turn, transmission of the virus to
others. Data from clinical trials for all three vaccines and
observational studies for the two mRNA vaccines clearly establish that
fully vaccinated persons have a greatly reduced risk of SARS-CoV-2
infection compared to unvaccinated individuals (see FDA, December 11,
2020; FDA, December 18, 2020; FDA, February 26, 2021).
    More importantly, vaccination is the single most effective method
for protecting workers from the most serious consequences of a COVID-19
infection: Hospitalization and death. Although symptomatic infections
can occur in fully vaccinated people, they are less likely to occur,
and are far less likely to result in severe health outcomes or death.
As discussed in Grave Danger (Section III.A. of this preamble), studies
have established that the available COVID-19 vaccines are highly
effective at preventing hospitalization, and even more effective at
preventing death. For example, one study found that unvaccinated adults
age 18 to 49 were 15.2 times more likely to be hospitalized and 17.2
times more likely to die of COVID-19 than fully vaccinated people in
the same age range, and unvaccinated adults age 50 to 64 were 10.9
times more likely to be hospitalized and 17.9 times more likely to die
than their fully vaccinated peers (Scobie et al., September 17, 2021).
The New York Times reported on October 1, 2021, that of the
approximately 100,000 individuals who died of COVID-19 since mid-June
2021, less than 3% had been identified by the CDC as vaccinated
individuals (Boseman and Leatherby, October 1, 2021).
    Vaccines are also uniquely effective when compared to non-
pharmaceutical methods for controlling exposure to COVID-19 at the
workplace. To be sure, non-pharmaceutical controls play an important
role in employers' efforts to prevent exposure to the virus; as
discussed in detail earlier, OSHA has, throughout the pandemic, advised
employers to implement various administrative, engineering, and other
controls to reduce workplace exposure to the virus. And, for certain
work settings in the healthcare industry where people with COVID-19 are
reasonably expected to be present, OSHA both encouraged vaccination and
mandated a suite of protections, many of which involve physical
controls (see 29 CFR 1910.502). Indeed, workers who work indoors and
near others are best protected from COVID-19 when they are fully
vaccinated and their exposure to COVID-19 is reduced (to the extent
possible) by non-pharmaceutical controls.
    Non-pharmaceutical controls, however, focus on preventing employee
exposure to the virus, and do not directly affect an employee's immune
response if exposure to the virus does occur. Additionally, non-
pharmaceutical controls often rely on the actions of individuals and/or
the integrity of equipment to be effective; for example, to use PPE to
control exposure, a worker must correctly don appropriate PPE each time
there is potential exposure, must properly clean, store, and maintain
the PPE between uses, and must replace the PPE when it is no longer
effective (see, e.g., 29 CFR 1910.132 (general PPE requirements in
general industry workplaces)). Accordingly, OSHA standards have always
followed the principle of the hierarchy of controls, under which
employers must control hazards by means other than PPE whenever
feasible, and PPE is a supplementary control. See e.g., 29 CFR
1910.134(a); 29 CFR 1910.1030(d)(2).
    Physical distancing requires workers to maintain constant awareness
of their environment in order to avoid coming into close proximity with
colleagues, customers, or other individuals, even though the realities
of their jobs and/or the design of the workplace may be unaccommodating
to that effort. Requiring employees to examine themselves for signs and
symptoms consistent with SARS-CoV-2 infection before reporting to work
is prone to human error and entirely ineffective when the employee is
infected but asymptomatic or pre-symptomatic.
    In contrast, a worker is considered fully vaccinated after
completing primary vaccination with a COVID-19 vaccine, or the second
dose of any combination of two doses of a COVID-19 vaccine that is
approved, authorized, or listed as a two-dose primary vaccination by
the FDA or WHO (see the Summary and Explanation for paragraph (c),
Section VI.C. of this preamble). Once fully vaccinated, a worker enjoys
automatic and long-lasting benefits; namely, a drastic reduction in the
risk of severe health effects or death. The vaccine works by bolstering
the worker's immune system and does not depend on the worker's acumen
or actions to afford its protection. Moreover, where an employer
implements one or more non-pharmaceutical controls at the workplace,
vaccination provides workers with a backstop of protection that greatly
reduces their risk of serious health effects if they are exposed to the
virus despite the presence of other controls. Vaccination thus ensures
that workers need not rely on other factors, be it the workplace
environment, the effectiveness of equipment, or the actions of other
individuals, to be substantially protected from the worst potential
outcomes of a COVID-19 infection.
    This ETS focuses on encouraging vaccination because it is the most
efficient and effective method for addressing the grave danger.
Vaccination is patently appropriate and feasible for almost every
worker in all industries, and will drastically reduce the risk that
unvaccinated workers will suffer the serious health outcomes associated
with SARS-CoV-2 infection. As described in Section III.A. of this
preamble (Grave Danger), employees who are unvaccinated are in grave
danger from the SARS-CoV-2 virus, but employees who are fully
vaccinated are not. Since it is the lack of vaccination that results in
grave danger, vaccination will best allay the grave danger. This ETS,
which is designed to strongly encourage vaccination, is thus
``necessary to protect employees'' from a grave danger. 29 U.S.C.
655(c).
    OSHA continues to encourage employers to implement additional
controls that may be appropriate to eliminate exposure to the SARS-CoV-
2 virus at their workplace, but, as discussed further below, OSHA has
not required employers to implement a comprehensive and multilayered
set of COVID-19 exposure controls in this ETS. This decision reflects
the extraordinary and exigent circumstances have required OSHA to
immediately promulgate this emergency temporary standard. Although OSHA
was able to design a comprehensive infection prevention program for the
specific healthcare settings to which the June 2021 Healthcare ETS
applied, this rule encompasses all industries covered by the OSH Act,
and targets unvaccinated workers in any indoor work setting not covered