COVID-19 Booster Shots: Top Questions Answered

Sept. 24, 2021 — The FDA and the CDC this week announced that certain groups of people at high risk for serious COVID-19 infection can now get a booster dose of the Pfizer vaccine.

You and your friends and family may have questions: Am I eligible? Where do I go to get a booster? Do I have to show proof of being high-risk? Am I still fully vaccinated if I’m eligible for a booster and don’t receive one?

We break down the most common questions about the updated Pfizer booster guidelines.

What are boosters?

A booster is an extra dose of vaccine to give you more protection against a disease; in this case, COVID-19.

“Basically, boosters are exactly what the word says,” according to Anita Gupta, DO, an adjunct assistant professor of anesthesiology and critical care medicine and pain medicine at the Johns Hopkins University School of Medicine.

“Boosters allow people to have an increased immune response.”

The extra dose of vaccine is especially important for the elderly and people with weakened immune systems from conditions like cancer, diabetes, or obesity, due to new variants being discovered, says Gupta.

“There’s a possibility that the immune response from the two-dose vaccine series may not be enough, especially in individuals who would be particularly vulnerable.

“So, the goal is really to help those individuals if they potentially were faced with new variants and to ensure that they don’t have any poor immune response if they’re faced with it.”

Who is eligible for the Pfizer booster?

Certain groups of people who have been fully vaccinated with the Pfizer vaccine for 6 months or longer can now receive a single Pfizer booster dose, according to updated FDA emergency use authorization guidelines.

You can’t receive the Pfizer booster if you received other COVID-19 vaccines, like Moderna or Johnson & Johnson.

You can get a Pfizer booster if you received the Pfizer vaccine and are a part of one of these groups:

1. 65 years old or older
2. 18 years old or older and at high risk for severe COVID-19
3. If you work or live in a situation that puts you at high risk for severe COVID-19. For example, health care workers, teachers, and people in prisons and homeless shelters.

Go here to see if you or someone you know is at high risk for severe COVID-19.

When can I expect to receive a Pfizer booster if I received another COVID-19 vaccine, like Moderna or Johnson & Johnson?

The exact date is unknown, but it shouldn’t take too long, given Moderna recently submitted data to the FDA, and Johnson & Johnson will be following suit very shortly.

U.S. Surgeon General Vivek H. Murthy, MD, on Friday said getting boosters approved for everyone, including those who originally got the Moderna or J&J vaccine, is a “high, high priority.”

William Schaffner, MD, a professor of preventive medicine and infectious diseases at Vanderbilt University, agrees it should happen soon.

“I would hope that within the next month to 6 weeks, we will get information about both of those vaccines,” he says. “It will be one right after the other. Each one dealt with separately.”

“I know it leads to a certain amount of confusion, but that’s the way you have to do it because all the data were not assembled at exactly the same time.”

Just the fact that Pfizer boosters are now available to certain high-risk groups is a big sign that boosters for other COVID-19 vaccines aren’t far behind, says Eric Ascher, DO, a family medicine physician at Lenox Hill Hospital in New York City.

“To me, that is a strong indicator that they will be made available to the rest of the population soon,” he says.

Where do I go get my Pfizer booster and how much will it cost?

You can get your booster shot at pharmacies, your doctor’s office, health departments, occupational clinics, and federal programs, according to the CDC.

“Over 70% of current COVID-19 administration” occurs in pharmacies, the CDC states.

Boosters for all COVID-19 vaccines are completely free.

“All COVID-19 vaccines, including booster doses, will be provided free of charge to the U.S. population,” the CDC said Thursday.

Do I need to show proof of having received the Pfizer vaccine before getting a Pfizer booster?

The short answer is probably not. But for your safety, it’s important to follow FDA guidelines and only get a Pfizer booster if you received the Pfizer vaccine, Schaffner says.

“That has already opened the door to people who have not been vaccinated with Pfizer who are very eager to get a booster, to go ahead and get a booster. That’s not recommended,” he says.

“We always caution people that, while this is unlikely, should you experience an adverse event, if you’re doing it outside the set recommendation, your insurance won’t cover it.”

Do we have to show proof of being high risk due to an underlying medical condition or that we live or work in a place that puts us at high risk for severe COVID-19, or that we are older than 65?

No.

It will work on the honor system, Schaffner says. “In other words, you show up and say you’re eligible, you won’t be quizzed about it, and the location, whether it’s a pharmacy or vaccination site, will give you the booster.

“This is the same procedure we already have in place for people who are immunocompromised. All they have to do is show up and say, ‘I’m in an immunocompromised group,’ and they get the third dose.”

Are boosters a full dose or half dose of the Pfizer vaccine?

A Pfizer booster is one full dose of Pfizer vaccine, according to the FDA.

But this may not be the same for other COVID-19 vaccine boosters.

“For example, the FDA is considering whether to authorize a lower dose of the Moderna COVID-19 vaccine booster than the dose given in the first two shots,” Gupta says.

But you shouldn’t be too hung up on the dose of your booster shot.

“This is based on the makeup of the vaccine and does not change the level of protection,” Ascher says.

If I am fully vaccinated but haven’t received a booster, am I still considered fully vaccinated?

Yes.

“Based on current data, the definition of ‘fully vaccinated’ would remain the same after recommendations for booster dose,” the CDC says.

A person is considered fully vaccinated 2 weeks after they complete their initial vaccination series, like two doses of the Moderna and Pfizer vaccines or one dose of the Johnson & Johnson vaccine.

When it comes to people who are immunocompromised, it can be a bit more complicated, says Gupta.

“For clarity’s sake, if you are immunocompromised, we’ll call your third shot a third dose. Third doses for immunocompromised people are available now. If you’re not immunocompromised, a third shot is considered a booster.

“According to the CDC, those with moderately to severely compromised immune systems are especially vulnerable to COVID-19 and may not build the same level of immunity to two-dose vaccine series, compared to people who are not immunocompromised. This additional dose intends to improve immunocompromised people’s response to their initial vaccine series.”

Is this going to be an annual booster, like flu vaccines?

“We don’t know that yet,” Schaffner says. “We would anticipate that these boosters, because they really boost and increase your antibody levels to a very high level, would provide rather prolonged protection. How long? Well, we’ll have to see.

“Remember, we’re learning about COVID-19 and COVID-19 vaccinations as we go along, so we can’t predict at the moment whether this will be an annual booster, or every 2 years, or every 3 years. We’ll just have to see.”

Should I expect the same side effects that I experienced when I received my initial doses of COVID-19 vaccine?

You may experience similar side effects, like arm soreness, mild flu, body aches, and other common symptoms, according to the CDC.

But it’s important to remember that everyone reacts differently to vaccines, says Ascher.

“I have had patients (as well as personal experience) where there were none to minimal symptoms, and others who felt they had a mild flu for 24 hours,” he says.

“I expect no side effects greater than what was felt with your prior doses. The vaccine is very safe, and the benefit of vaccination outweighs the risks of any mild side effects.”

If you’d like more information, you can check out the CDC and U.S. Department of Health and Human Services websites for updates on COVID-19 vaccines and boosters. You can also reach out to your doctor or other health care providers to learn more.