Experts Address 3 Major COVID-19 Vaccine Concerns Among Americans

COVID vaccine vial

Leon Neal / Staff / Getty Images

Key Takeaways

  • A recent survey shows many Americans are hesitant to get the COVID-19 vaccines, some citing fears of possible side effects and questions about effectiveness as reasons.
  • Infectious disease experts stress that the data collected from the Pfizer/BioNTech and Moderna vaccine trials are very reassuring in terms of both efficacy and safety.
  • Experts say it’s important to think of the vaccine as a part of the overall COVID-19 prevention strategy. By accepting the vaccine, you will help our country achieve herd immunity.

While two COVID-19 vaccines are now authorized for use in the United States, not everyone is eager to get in line once their priority group is called. According to a Kaiser Family Foundation survey published on December 15, about a quarter (27%) of the public are vaccine hesitant,﻿﻿ saying they “probably or definitely would not get a COVID-19 vaccine even if it were available for free and deemed safe by scientists.”

The survey found that those who were hesitant to get a COVID-19 vaccine were worried about multiple things, including possible side effects (59%), lack of trust in the government to ensure the vaccines’ safety and effectiveness (55%), and concerns that the vaccine is too new (53%).

To address these concerns, Verywell spoke with infectious disease experts from all over the country.

Concern #1: The vaccine was developed so fast. It must have been rushed and therefore isn’t safe.

The speed at which the Pfizer-BioNTech and Moderna vaccines were both developed and authorized is a stark contrast compared to how long other human disease vaccines have taken to create. The mumps vaccine, which held the previous record, took about four years. However, scientists can point to a few different reasons why the COVID-19 vaccines have a different timeline.

A lot of events conspired to make the vaccines available so quickly, but it wasn’t because of any shortcuts, Timothy Brewer, MD, an epidemiologist and professor of medicine at UCLA's Fielding School of Public Health, tells Verywell.

Brewer points to the fact that both vaccines made by Pfizer and Moderna are mRNA vaccines, and the mRNA platform was already in development (though not net used in a human vaccine). By using a small part of the virus’s genetic code (RNA), an mRNA vaccine shows cells how to make a coronavirus protein that our immune system can recognize and then respond to. After someone gets vaccinated, if they're exposed to COVID-19, their body will already have the antibodies to fight it off and keep it from entering cells.

“People have to realize that the vaccines are actually developed based on years and years of experience,” Brewer says. “For example, the Moderna vaccine took the platform (mRNA) that they had for a MERS (Middle East respiratory syndrome) vaccine, and they swapped out the MERs genetic code and swapped in the SARS-CoV-2 genetic code. So, these vaccines didn’t come out of nowhere; they came out of years of research and advances in technology.”

Is mRNA Safe?

While some vaccines use live virus or bacterium to teach our immune system how to fight the pathogens, an mRNA vaccine doesn't use the live virus, and therefore cannot give someone COVID-19, according to the Centers for Disease Control and Prevention (CDC).﻿﻿ Additionally, mRNA from the vaccine never enters the nucleus of the cell, meaning it does not affect or interact with human DNA.

Brewer says that the timeline behind the actual manufacturing of the vaccines had a huge impact on how quickly they could be deployed after authorization from the Food and Drug Administration (FDA).

“Usually, companies don’t commit to manufacturing vaccines until they’ve been approved. And governments or healthcare systems don’t buy vaccines until they’ve been approved,” Brewer says. “But what was really sped up under Operation Warp Speed was the commitment to purchase millions of doses of vaccine before they had been approved. That allowed manufacturing to rev up, even while the vaccines were going through the study and approval process.”

Concern #2: The government and health agencies have been giving mixed messages about COVID-19 since the beginning. Why trust them about a vaccine?

A large complaint among Americans is the contradictory messages from the CDC and healthcare officials like Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health (NIH). For example, in an interview on March 8, 2020, Fauci said “there’s no reason to be walking around with a mask.” But by April 3, the CDC updated its previous advice and recommended people wear face coverings “in public settings when around people outside their household, especially when social distancing measures are difficult to maintain.”

Rupali Limaye, MD, an associate scientist at Johns Hopkins Bloomberg School of Public Health, tells Verywell that part of the issue regarding these messages is that they had to change. And that's because science—and the virus—is always evolving.

“The great news is that as we learn about the virus, we can update recommendations to reflect that latest data, which is what happened with the mask wearing example,” Limaye says. “People saw that as. ‘Oh, public health entities don’t know what they’re talking about.’ But my argument is: This is us showing you that science is working; that we’re making progress; that we're learning about it and able to use evidence to tell you what to do next.”

Bruce Hirsch, MD, an infectious disease expert at Northwell Health in New York, says that at some point, people need to put their faith in organizations like the FDA and CDC.

“I think the objections to the vaccine are understandable because the vaccine is brand new, but it’s not entirely intellectually consistent with some of the other actions that we take and the other risks that we take day in and day out of our lives,” Hirsch says.

When you go to the grocery store, you trust that the food you’re buying doesn’t contain salmonella and won't make you sick. When you drive a car, you trust that your vehicle has passed industry safety regulations and won’t malfunction. But there are—and will—be rare occasions when that head of lettuce gives you salmonella, and the car you drive breaks down, Hirsch says.

“Unless you’re growing your own food and living off the grid, you have established some trust into societal norms," he says, citing FDA-authorized vaccines as societal norms.

Concern #3: The side effects of the vaccines haven’t been observed long enough.

In clinical trial data presented to the FDA by Pfizer, the vaccine was well-tolerated in approximately 44,000 participants with no serious safety concerns. Side effects were mild, including fatigue and headache in fewer than 3% of participants.﻿﻿

Moderna presented similar findings. The company reported that the majority of side effects among its 30,000 vaccine clinical trial participants were mild or moderate. After the first dose, 2.7% of participants reported pain at the injection site.﻿﻿

The FDA says there is a “remote chance” that the Pfizer vaccine could cause a severe allergic reaction, which would occur within minutes or up to an hour after receiving the vaccine.﻿﻿

Robert Jacobson, MD, a Mayo Clinic pediatrician in the department of Community Pediatric and Adolescent Medicine, tells Verywell he doesn't know of any vaccines that have caused side effects more than six weeks after being administered.

“We have a track record with vaccines not causing long-lasting harm that shows up months later,” Jacobson says. “We also have a process in place to watch for those just in case. But it would be very different from what science has taught us about how these vaccines behave; it would be incredibly unusual to see [delayed effects].”

Jacobson adds that mRNA vaccines quickly deteriorate inside the body.

“It’s not like there’s a lasting vaccine that stays with the person; it actually disappears in a matter of hours to days," he says. "In fact, that’s why we need two doses."

What This Means For You

Infectious disease experts believe and agree with the science and data that prove the two COVID-19 vaccines approved for use in the U.S.—the Moderna and Pfizer-BioNTech vaccines, are safe and effective. Getting the vaccine when it becomes available to you will help our country reach herd immunity and play a pivotal part in getting back to normalcy.


Was this page helpful?
5 Sources
  1. Hamel L, Kirzinger A, Munana C, Brodie M. KFF COVID-19 vaccine monitor: December 2020. Kaiser Family Foundation. Updated December 15, 2020.

  2. Centers for Disease Control and Prevention. Understanding mRNA COVID-19 vaccines. Updated December 18, 2020.

  3. Food and Drug Administration. Vaccines and Related Biological Products Advisory Committee meeting December 10, 2020. FDA briefing document: Pfizer-BioNTech COVID-19 vaccine. Updated December 10, 2020.

  4. Moderna. Moderna’s COVID-19 vaccine candidate meets its primary efficacy endpoint in the first interim analysis of the phase 3 COVE study. Updated November 16, 2020.

  5. Food and Drug Administration. Fact sheet for recipients and caregivers emergency use authorization (EUA) of the Pfizer-BioNTech COVID-19 vaccine to prevent coronavirus disease 2019 (covid-19) in individuals 16 years of age and older. Updated December 2020.