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Hepatitis A

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What is hepatitis A?
Hepatitis A is a liver disease caused by hepatitis A virus (HAV).
What are the signs and symptoms of hepatitis A?
Illness caused by HAV infection typically has an abrupt onset that can include fever, malaise, anorexia, nausea, abdominal discomfort, dark urine, and jaundice. The likelihood of having symptoms with HAV infection is related to age. In children younger than age 6 years, 70% of infections are asymptomatic. When illness does occur in young children, it is typically not accompanied by jaundice. In older children and adults, infection typically is symptomatic, with jaundice occurring in more than 70% of patients.
Hepatitis A signs and symptoms usually last less than 2 months, although 10% to 15% of symptomatic people have prolonged illness (usually referred to as relapsing hepatitis A) lasting up to 6 months.
How is HAV transmitted?
Person-to-person spread through the fecal-oral route is the primary means of HAV transmission. Among those for whom the Centers for Disease Control and Prevention (CDC) has risk factor/behavior data (1,169 out of 1,987 cases in 2009), 44% indicated no risk factors. Among the 290 cases (15%) who indicated one or more risk factors, food and water-borne hepatitis A represented the most frequent reported exposure (68 cases) and international travel remained the behavior that produced the most cases of hepatitis A (119 cases). Casual contact, as in the usual office, factory, or school setting does not transmit the virus.
Common-source outbreaks and sporadic cases also can occur from exposure to fecally- contaminated food or water. Uncooked HAV-contaminated foods have been recognized as a source of outbreaks. Cooked foods also can transmit HAV if the temperature during food preparation is inadequate to kill the virus or if food is contaminated after cooking, as occurs commonly in outbreaks associated with infected food handlers.
What is the incubation period for hepatitis A?
HAV can produce either asymptomatic or symptomatic infection in humans after an average incubation period of 28 days (range: 15-50 days).
How is HAV shed?
In infected people, HAV replicates in the liver, is excreted in bile, and is shed in stool. Peak infectivity of infected people occurs during the 2-week period before onset of jaundice or elevation of liver enzymes, when concentration of virus in stool is highest. Concentration of virus in stool declines after jaundice appears. Children can shed HAV for longer periods than do adults, lasting up to 10 weeks after onset of clinical illness.
How common is HAV infection in the United States?
In 2009, 1,987 acute clinical cases were reported to CDC's surveillance system. It is felt this number is grossly underestimated. Approximately 215,000 new infections were estimated to have occurred during this same time period. Historically, acute hepatitis A rates vary cyclically, with nationwide increases every 10–15 years. The last peak was in 1995; since that time, rates of hepatitis A have steadily declined.
What is the seroprevalence of HAV infection in the United States?
As evidenced by the last National Health and Nutrition Examination Survey (NHANES) done during 2005, approximately 29.1%-33.5%% of the U.S. population had serologic evidence of previous HAV infection.
Do people die from hepatitis A?
Yes. The case fatality rate for reported cases of hepatitis A is about 0.9% of reported cases. Older age and chronic liver disease increases one's risk of dying from hepatitis A.
Who is most at risk for acquiring HAV infection?
People who are at increased risk for HAV infection include the following:
certain travelers to countries that have high or intermediate endemicity of HAV infection (for map of endemic areas, see http://wwwn.cdc.gov/travel)
  men who have sex with men (MSM)
  people who have clotting-factor disorders, such as hemophilia
  users of injection and noninjection illegal drugs
  people who have oral-anal sexual contact with someone who has hepatitis A
  people working with nonhuman primates
Discuss the tests commonly used to diagnose hepatitis A.
Hepatitis A cannot be differentiated from other types of viral hepatitis on the basis of clinical or epidemiological features alone. Appropriate blood tests must be used.
Anti-HAV: Total antibody to HAV. This diagnostic test detects total antibody of both IgG and IgM subclasses of HAV. Its presence indicates either acute or resolved infection.
  IgM anti-HAV: IgM antibody is a subclass of anti-HAV. Its presence indicates a recent infection with HAV (6 months or less). It is used to diagnose acute (recently acquired) hepatitis A.
Total anti-HAV, which appears early in the course of infection, remains detectable for the person's lifetime and provides lifelong protection against the infection/disease. To confirm a diagnosis of acute HAV infection, serologic testing for IgM anti-HAV is required. In the majority of persons, serum IgM anti-HAV becomes detectable 5 to 10 days before onset of symptoms and lasts about 6 months. However, there have been reports of persons who test positive for IgM anti-HAV for up to a year or more following infection. For a complete educational program on the interpretation of viral hepatitis serology that includes hepatitis A serology, visit www.cdc.gov/hepatitis/Resources/Professionals/Training/SerologyStart.htm or the hepatitis web study at: http://depts.washington.edu/hepstudy
Can HAV be transmitted by blood?
Yes. On rare occasions, HAV infection has been transmitted by transfusion of blood or blood products collected from donors during the viremic phase of their infection (i.e., when HAV is in the donor's blood).
Is HAV transmitted by saliva?
In experimentally infected nonhuman primates, HAV has been detected in saliva during the incubation period; however, transmission by human saliva has not been reported.
How common is HAV transmission in hospital settings?
Hospital-acquired HAV infection is rare. Outbreaks have occasionally been observed in neonatal intensive care units when infants acquire infection from HAV-infected transfused blood and subsequently transmit HAV to other infants and staff. Outbreaks of hepatitis A caused by transmission from adult patients to healthcare personnel (HCP) are typically associated with fecal incontinence, although the majority of hospitalized patients who have hepatitis A are admitted after onset of jaundice, when they are beyond the point of peak infectivity. Data from serologic surveys of HCP have not indicated an increased prevalence of HAV infection in these groups compared with that in control populations.
How stable is HAV in the environment?
Depending on conditions, HAV can be stable in the environment for months. Heating foods at temperatures greater than 185°F (85°C) for 1 minute or disinfecting surfaces with a 1:100 dilution of sodium hypochlorite (i.e., household bleach) in tap water will inactivate HAV.
Do people with hepatitis A develop chronic disease?
No, there is no chronic (long-term) infection. Once you have had HAV infection and recovered, you cannot get it again.
Vaccination Recommendations Back to top
What is the best way to prevent HAV infection?
Vaccination with the full 2-dose series of hepatitis A vaccine is the best way to prevent HAV infection. Immune globulin (IG) can also be used for short-term protection in certain situations.
Where can I find information about vaccine shortages?
For detailed information about hepatitis A vaccine shortages, go to CDC's website at www.cdc.gov/vaccines/vac-gen/shortages.
Who is recommended to receive hepatitis A vaccine?
According to CDC, people recommended for vaccination include
All children at age 1 year (12-23 months). Children who have not received the 2nd dose by age 2 years should be vaccinated as soon as feasible. Additionally, hepatitis A vaccine is recommended for children older than 23 months who live in areas where vaccination programs target older children, or who are at increased risk for infection, or for whom immunity against hepatitis A is desired.
  Men who have sex with men
  Users of illegal drugs, injectable or noninjectable
  People who have blood clotting disorders
  People who work with HAV-infected primates or with HAV in a research laboratory setting (no other groups have been shown to be at increased risk for HAV infection because of occupational exposure)
  People with chronic liver disease
  Any person who wishes to be immune to hepatitis A
Hepatitis A vaccine is not routinely recommended for healthcare personnel, sewage workers, or day care providers.
Should we give hepatitis A vaccine to a person older than age 23 months who request it?
Yes, unless the person is allergic to any of the vaccine components. Hepatitis A vaccine is safe and effective and is recommended for any person who wishes to obtain immunity.
Which children should be vaccinated against HAV infection on a routine basis?
All children should receive 2 doses of hepatitis A vaccine beginning at age 1 year (i.e., 12-23 months). The 2 doses in the series should be administered at least 6 months apart. Children who are not vaccinated by age 2 years can be vaccinated at subsequent visits. States, counties, and communities with existing hepatitis A vaccination programs for children age 2-18 years are encouraged to maintain these programs. Efforts focused on routinely vaccinating 1-year-olds should enhance, not replace, ongoing programs directed at a broader population of children. For a copy of the ACIP recommendations on hepatitis A, go to www.cdc.gov/mmwr/PDF/rr/rr5507.pdf
For hepatitis A vaccination, the recommended interval between the 2-dose series is at least 6 months. Is this the same as 24 weeks?
No. The recommended interval between dose #1 and #2 of hepatitis A vaccine is 6 calendar months, not 24 weeks. See CDC's Pink Book (Epidemiology and Prevention of Vaccine Preventable Diseases) available at www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendices/A/age-interval-table.pdf, footnote 5.
I thought hepatitis A vaccine was recommended for all children. Why does the bar on CDC's childhood immunization schedule indicate that hepatitis A vaccine should be routinely given to children ages 12 through 23 months, but not be given to children age 2 years and older unless they are in certain high risk groups? In our practice in a historically "low-risk" state, we currently give hepatitis A vaccine to any unvaccinated child. Is this incorrect?
No. Though the ACIP recommendation says children ages 12 through 23 months should routinely be vaccinated with 2 doses of hepatitis A vaccine, it also says, "children who are not vaccinated by age 2 years can be vaccinated at subsequent visits."
What are the recommendations for postexposure prophylaxis for hepatitis A?
The CDC recommendations published in October 2007 (www.cdc.gov/mmwr/preview/mmwrhtml/mm5641a3.htm), state that hepatitis A vaccine is preferred over immune globulin (IG) for postexposure prophylaxis for people ages 12 months-40 years who have recently been exposed to HAV and who have not previously received hepatitis A vaccine. Previously, IG was preferred. People age 12 months-40 years should receive a single dose of single-antigen hepatitis A vaccine or IG (0.02 mL/kg) as soon as possible after exposure. For people older than 40 years, IG is preferred, although vaccine can be used if IG is unavailable. It is important to note that IG should be given within 2 weeks of exposure to HAV. IG should also be used for children younger than age 12 months, immunocompromised people, people who have chronic liver disease or other chronic medical conditions, and persons for whom vaccine is contraindicated. The following are situations in which postexposure treatment is indicated:
Having close, ongoing personal contact with an HAV-infected person
Working in or attending a child care center where hepatitis A cases are occurring
Having common-source exposure (e.g., eating HAV-infected food in a restaurant)
Having close contact with index patients in schools, hospitals, and work settings when an epidemiological investigation indicates that a common-source exposure has occurred.
People who have received a dose of hepatitis A vaccine before exposure to HAV do not need to receive a second dose of vaccine until at least 6 months following the first dose. Because HAV infection cannot be reliably diagnosed on clinical presentation alone, serologic confirmation of HAV infection in the index patient is recommended using the IgM anti-HAV serologic test. If the index patient tests positive, postexposure treatment of sex and household contacts is recommended (as described above). Serologic screening of contacts for HAV immunity before administering postexposure prophylaxis is not recommended because screening results in delayed prophylaxis. It is critical that you contact your local or state health department to get guidance on when or if postexposure treatment is recommended.
When should prevaccination anti-HAV testing for susceptibility be performed?
Testing is not indicated for children because of their expected low prevalence of infection. In populations that have expected high rates of previous HAV infection, prevaccination screening may be considered to reduce costs. People to consider for testing include: (1) adults who were either born in or lived for extensive periods in geographic areas that have a high or intermediate endemicity of hepatitis A; (2) older adolescents and adults in certain population groups (e.g., American Indians, Alaska Natives, Hispanics); and (3) adults in risk groups that have a high prevalence of infection (e.g., men who have sex with men, illegal drug users). In addition, HAV testing may be cost effective among people older than age 40 years.
When should postvaccination testing be performed?
Postvaccination testing is not indicated because of the high rate of vaccine response among adults and children. In addition, not all testing methods approved for routine diagnostic use in the United States have the sensitivity to detect low, but protective, anti-HAV concentrations after vaccination.
For Special Groups Back to top
Explain the details regarding the recommendation for giving hepatitis A vaccine to people who will be in contact with recently adopted children.
The Advisory Committee on Immunization Practices (ACIP) voted in February 2009 to recommend vaccination against HAV infection for all previously unvaccinated people who anticipate having close personal contact with an international adoptee from a country of high or intermediate endemicity during the first 60 days following the adoptee's arrival in the U.S. In addition to the adoptee's new parents and siblings, this group could include grandparents and other members of the extended family, caregivers, and healthcare providers. Ideally, the first dose of hepatitis A vaccine should be given to close contacts as soon as adoption is planned but no later than 2 weeks prior to the arrival of the adoptee. A second dose should be given no sooner than 6 months after the first dose.
Should HCP be vaccinated routinely against hepatitis A?
No. A number of studies have shown that HCP are not at increased risk of HAV infection because of their occupation. However, if the he/she is going to work (or vacation) in a country with a high or intermediate endemic rate of HAV infection, he/she is at risk of HAV infection and should be vaccinated. The only HCP for whom hepatitis A vaccine is routinely recommended are those who work with primates or live HAV.
Should daycare workers be routinely vaccinated against hepatitis A?
No. Although child care centers might have been the source of outbreaks of hepatitis A in certain communities, disease in child care centers more commonly reflects extended transmission from the community.
Can pregnant women receive hepatitis A vaccine?
The safety of hepatitis A vaccination during pregnancy has not been determined; however, because hepatitis A vaccine is produced from inactivated HAV, the theoretical risk to the developing fetus is expected to be low. The risk associated with vaccination should be weighed against the risk for hepatitis A in pregnant women who might be at high risk for exposure to HAV.
Can lactating women receive hepatitis A vaccine?
Yes. Hepatitis A vaccine is an inactivated vaccine and poses no harm to the nursing infant.
Why is hepatitis A vaccination recommended for people with chronic liver disease?
Although not at increased risk for HAV infection, people with chronic liver disease are at increased risk for fulminant hepatitis A if they should become infected with HAV. For this reason, hepatitis A vaccination is recommended for them.
Can hepatitis A vaccine be given to immunocompromised people?
Yes. If an immunocompromised person has a risk factor that places them at increased risk of hepatitis A (e.g., MSM), they should be vaccinated with hepatitis A vaccine.
I have a patient on interferon for hepatitis C, but I want to give him hepatitis A vaccine. Is it okay to vaccinate him against hepatitis A while he is on interferon?
Yes. Hepatitis A vaccine should be given to all susceptible patients with chronic liver disease. Hepatitis A vaccine is very immunogenic and the patient's diminished immune status due to interferon should not affect the immunogenicity and effectiveness of the vaccine, although there are no data to support that statement.
Why isn't hepatitis A vaccine recommended for sewage and solid waste disposal workers?
Existing data do not support the use of hepatitis A vaccine routinely in this setting. In published reports of three serologic surveys conducted among United States wastewater workers and appropriate comparison populations, no substantial or consistent increase in the prevalence of anti-HAV was identified among wastewater workers. No work-related instances of HAV transmission have been reported among wastewater workers in the United States.
Are people with developmental disabilities at risk of HAV infection?
Historically, HAV infection was highly endemic in institutions for people with developmental disabilities. As fewer children have been institutionalized and as conditions in institutions have improved, the incidence and prevalence of HAV infection have decreased, although outbreaks can occur in these settings. Children with developmental disabilities should receive hepatitis A vaccine according to U.S. routine vaccine recommendations. Employees in these institutional settings are not recommended to receive routine hepatitis A vaccination; however, employees and residents in these settings should receive hepatitis B vaccination routinely.
Schedules Vaccines Back to top
What are the hepatitis A vaccines that are approved for use in the United States?
Recommended dosages and schedules of hepatitis A vaccines
Vaccine Age group Dose Volume # Doses Schedule
(GlaxoSmithKline [GSK])
1-18 years 720 El.U.* 0.5 ml 2 0, 6-12 mos.
19 years and older 1440 El.U.* 1.0 ml 2 0, 6-12 mos.
(Merck & Co.)
1-18 years 25 U* 0.5 ml 2 0, 6-18 mos.
19 years and older 50 U* 1.0 ml 2 0, 6-18 mos.
*El.U. = Elisa Units **U = Units
Combination vaccine using hepatitis A and hepatitis B vaccines
Vaccine Age group Antigens used Volume # Doses Schedule
(GlaxoSmithKline [GSK])
18 years and older Havrix (720 El.U.) combined
with Engerix-B
(20 mcg)
1.0 ml 3 0, 1, 6 mos.
4 0, 7, 21-30 days, 12 months
Are hepatitis A vaccine brands interchangeable?
Yes, a number of studies indicate that the two brands of hepatitis A vaccine, Havrix (GlaxoSmithKline [GSK]) and Vaqta (Merck), are interchangeable.
Can hepatitis A vaccine be given concurrently with other vaccines?
Yes. Other inactivated and/or live virus vaccines can be administered at the same time as hepatitis A vaccine, but should be given at a different anatomical site, if possible. If given in the same muscle, separate the injections by a minimum distance of 1 inch.
Could you please provide more information about Twinrix (the combination hepatitis A and B vaccine) and the two schedules for its use?
Twinrix (GSK) is an inactivated combination vaccine containing both hepatitis A virus (HAV) and hepatitis B virus (HBV) antigens. The vaccine contains 720 EL.U. of hepatitis A antigen (half of the Havrix adult dose) and 20 mcg of hepatitis B antigen (the full Engerix-B adult dose). In the U.S., Twinrix is licensed for use in people who are age 18 years or older. It can be administered to people who are at risk for both hepatitis A and hepatitis B, such as certain international travelers, men who have sex with men, illegal drug users, or to people who simply want to be immune to both diseases. Primary immunization consists of 3 doses given intramuscularly on a 0, 1, and 6 month schedule. In March 2007, the FDA also approved a 4-dose schedule for Twinrix. It consists of 3 doses given within 4 weeks, followed by a booster dose at 12 months (0, 7 days, 21-30 days, and 12 months). The 4-dose schedule could benefit individuals needing rapid protection from hepatitis A and hepatitis B, such as people traveling to high-prevalence areas imminently and emergency responders, especially those being deployed to disaster areas overseas. Twinrix cannot be used for postexposure prophylaxis.
By what method should hepatitis A vaccine be administered?
Hepatitis A vaccine should be administered intramuscularly (IM), using the appropriate injection site and needle size as determined by the patient's age and body mass.
Is hepatitis A vaccine available to children through the Vaccines for Children (VFC) program?
Yes, VFC-supported hepatitis A vaccine is available for children 12 months through 18 years who are VFC-eligible and who meet the criteria for vaccination with hepatitis A vaccine. In addition, combination hepatitis A and hepatitis B vaccine (Twinrix by GSK) is also available for people who are age 18 years who are VFC-eligible.
What contraindications and precautions should be followed when administering hepatitis A vaccine?
Hepatitis A vaccine is contraindicated for people with a history of a severe allergic reaction to a previous dose of hepatitis A vaccine or to a vaccine component. As with all other vaccines, there is a precaution when giving it to anyone who is moderately or severely ill. Information on the use of hepatitis A vaccine in pregnancy is noted in a previous question.
What local reactions might occur after administration of hepatitis A vaccine?
No serious adverse events have been attributed definitively to hepatitis A vaccine. Among adults, the most frequently reported side effects are soreness at the site of the injection and headache. In children, the most frequently reported side effect is soreness at the injection site. The frequency of side effects after administration of Twinrix is similar to those reported when the two single-antigen vaccines were administered.
What happens if dose #2 of hepatitis A vaccine is delayed?
You do not need to start the series over again. The immunogenicity of 1 dose of hepatitis A vaccine is 94% to 100%. Immunogenicity is considered to be equal to efficacy; however, the vaccine series should be completed to assure long-term protection.
To complete a 21-year-old patient's hepatitis A vaccine series, how many adult doses should I give if the patient received a single dose of pediatric hepatitis A vaccine 5 years ago?
You should give the patient one dose of adult hepatitis A vaccine to complete the 2-dose series. There is never a need to start a vaccine series over.
One of our staff gave a dose of pediatric hepatitis A vaccine to an adult patient by mistake. How do we remedy this error?
In general, if you give less than a full age-appropriate dose of any vaccine, the dose is invalid. You should revaccinate the person with the appropriate dose as soon as feasible.
There are, however, two exceptions to the general rule: (1) If a patient sneezes after receiving nasal-spray live attenuated influenza vaccine, count the dose as valid. (2) If an infant regurgitates, spits, or vomits during or after receiving oral rotavirus vaccine, count the dose as valid.
If you give more than an age-appropriate dose, count the dose as valid and notify the patient/parent about the error. Using larger than recommended dosages can be hazardous because of excessive local or systemic concentrations of antigens or other vaccine constituents.
Avoid such errors by checking the vaccine vial label 3 TIMES!
I have seen adults who have had 1 or 2 doses of Twinrix, but we only carry single-antigen vaccine in our practice. How should we complete their vaccination series with single-antigen vaccines?
Twinrix is licensed as a 3-dose series for people age 18 years and older. If Twinrix is not available or if you choose not to use Twinrix to complete the Twinrix series, you should do the following: If 1 dose of Twinrix was given, complete the series with 2 adult doses of hepatitis B vaccine and 2 adult doses of hepatitis A vaccine. If 2 doses of Twinrix were given, complete the schedule with 1 adult dose of hepatitis A vaccine and 1 adult dose of hepatitis B vaccine.
Another way to consider this is as follows:
A dose of Twinrix contains a standard adult dose of hepatitis B vaccine and a pediatric dose of hepatitis A vaccine. Thus, a dose of Twinrix can be substituted for any dose of the hepatitis B series but not for any dose of the hepatitis A series.
Any combination of 3 doses of adult hepatitis B or 3 doses of Twinrix = a complete series of hepatitis B vaccine.
  One dose of Twinrix + 2 doses of adult hepatitis A = a complete series of hepatitis A vaccine.
  Two doses of Twinrix + 1 dose of adult hepatitis A = a complete series of hepatitis A vaccine.
We're thinking of using Twinrix and we're wondering whether we can use it for doses #1 and #3 only and use single antigen hepatitis B vaccine for dose #2?
No. Twinrix contains 50% less hepatitis A antigen component than Havrix, GSK's monovalent hepatitis A vaccine [720 vs. 1440 El. U.], so the patient would not receive the recommended dose of hepatitis A vaccine antigen. For this reason, 3 doses of Twinrix must comprise the series.
Why does a 15-year old who weighs 160 lbs receive a pediatric dose of hepatitis A vaccine while his 110-pound mother receives an adult dose (twice the pediatric dose)?
The efficacy data from the clinical trials were based on age at time of vaccination, and not on the weight of the individual. Hence, the dosage recommendations reflect this age-based efficacy data. The same holds true for hepatitis B vaccine. In addition, higher response rates are expected in younger people, even if their weights are above the norm.
Immune Globulin Back to top
What is immune globulin (IG)?
IG is a sterile preparation of concentrated antibodies (i.e., immunoglobulins) made from pooled human plasma processed by cold ethanol fractionation. In the United States, only plasma that has tested negative for hepatitis B surface antigen, antibody to human immunodeficiency virus (HIV), and antibody to hepatitis C virus (HCV) is used to produce IG. In addition, the Food and Drug Administration requires that the process used to produce IG include a viral inactivation step or that final products test negative for HCV-RNA by polymerase chain reaction. Anti-HAV concentrations differ among IG lots, and decreasing concentrations have been observed over the preceding 30 years, probably because of the decreasing prevalence of previous HAV infection among plasma donors; however, no clinical or epidemiologic evidence of decreased protection has been observed.
How does IG work?
IG provides protection against HAV infection through passive transfer of antibody. Depending on the IG dosage, protection lasts from 3 to 5 months. When administered for preexposure prophylaxis, one dose of 0.02 mL/kg IM confers protection for less than 3 months, and one dose of 0.06 mL/kg IM confers protection for 3 to 5 months. When administered within 2 weeks after an exposure to HAV (0.02 mL/kg IM), IG is 80%-90% effective in preventing HAV infection. Efficacy is greatest when IG is administered early in the post-exposure period.
How is IG packaged and how is IG administered?
IG is available in single-use vials (2 mL and 10 mL). For administration of IG, an appropriate muscle mass (i.e., the deltoid or gluteal muscle) should be chosen into which a substantial volume can be injected, using a needle length appropriate for the person's age and size. If a gluteal muscle is used, the central region of the buttock should be avoided; only the upper outer quadrant should be used, and the needle should be directed anteriorly to minimize the possibility of injury to the sciatic nerve.
Does IG cause adverse events?
Serious adverse events from IG are rare. Anaphylaxis has been reported after repeated administration to people with known immunoglobulin A (IgA) deficiency; thus, IG should not be administered to these people.
Can pregnant or lactating women receive IG?
Yes. Pregnancy or lactation is not a contraindication to IG administration.
Travel - International Back to top
What are the hepatitis A vaccination recommendations for vaccination of travelers to protect them from HAV infection?
The recommendations (www.cdc.gov/mmwr/preview/mmwrhtml/mm5641a3.htm) state that (1) hepatitis A vaccine is recommended for healthy susceptible people ages 1 through 40 years who travel to or work in regions where hepatitis A is endemic and (2) hepatitis A vaccine should be given as soon as travel is considered, but it can be given any time prior to departure. For optimal protection in instances when departure will take place within two weeks, people older than age 40 years, immunocompromised people, and people with diagnosed chronic liver disease or other chronic medical conditions, should also receive IG simultaneously with the first dose of hepatitis A vaccine but at a different anatomic injection site. For travelers younger than age 1 year, IG alone is recommended because hepatitis A vaccine is not licensed for use in this age group. Hepatitis A is endemic in all regions except the United States, Western Europe, New Zealand, Australia, Canada, and Japan.
We have an adult patient who received the correct pediatric series of hepatitis A vaccine as a teenager and is now traveling abroad. Does the patient need an adult booster?
No. There is no recommendation for a booster dose of hepatitis A vaccine if a patient has completed the 2-dose series at any age.
Is it really necessary to vaccinate travelers to Latin America who will be staying in 4-star hotels?
Yes. Data have shown that people acquire HAV infection even in such places as 4-star hotels located in Latin America.
If a traveler received the first dose of hepatitis A vaccine more than one year ago and needs to travel abroad imminently, will the traveler need IG in addition to dose #2 prior to leaving?
No. Just give the final dose of hepatitis A vaccine prior to travel.
If an infant younger than age 12 months receives IG before travel to a hepatitis A endemic area, will he/she need hepatitis A vaccine before another trip to a hepatitis A endemic area?
Possibly. Since IG protects against HAV infection for only 3 to 5 months, depending on the dosage given, additional IG may be needed if the infant is not yet age 12 months. Once they have reached their first birthday, hepatitis A vaccine should be given.
Can VFC-eligible children who travel to HAV-endemic areas receive hepatitis A vaccine under the VFC program?
Yes. Hepatitis A vaccine is covered under VFC for eligible children for all indications recommended by ACIP, including travel to HAV-endemic areas.
If a person was born and grew up in a country where HAV infection is endemic (e.g., Vietnam, Mexico) and then moved to the United States at age 20, should that person receive hepatitis A vaccine before returning to visit his/her homeland?
It depends on whether that person has a history of HAV infection. Unless there are medical records that document prior HAV infection, serologic testing for immunity (positive test for total anti-HAV) is the only way to determine if vaccination is necessary. For people from countries with high rates of HAV infection, such as Vietnam and Mexico, serologic testing might be done to prevent unnecessary vaccination. The cost effectiveness of serologic testing, however, should be balanced against the possibility of delaying needed vaccination while awaiting test results.
If a person has had HAV infection, should they still receive the vaccine if planning international travel?
No, as long as there are medical records that document that the person was previously infected with HAV (i.e., positive test for total anti-HAV). If there is any doubt that the person actually was infected with HAV, hepatitis A vaccine or IG should be given. The vaccine or IG will not harm a person who is already immune. Refer to the first question in this section for further information.
In addition, CDC has issued a new VIS for MMRV, dated 5/21/10, which is available at http://www.immunize.org/vis and http://www.cdc.gov/vaccines/pubs/vis/downloads/vis-mmrv.pdf As with all other VISs, it should be given to the parent or vaccine recipient prior to vaccination to facilitate discussion about the vaccine between the patient and provider.
This page was reviewed on May 1, 2013