Should I Get the COVID-19 Booster?

On Friday, many more Americans became eligible to receive a booster dose of the Pfizer vaccine for COVID-19. In addition to immunocompromised people who are already approved to receive a third dose of the Pfizer or Moderna vaccines, with the new recommendation released by the Centers for Disease Control and Prevention, a wider group — such as healthy older Americans and front-line health care workers — who’ve already completed the two-dose Pfizer series can now get the third dose for added protection.

Boosters must be given at least six month after the primary Pfizer series, with specific guidelines for these groups:

— People ages 65 and older should receive a Pfizer booster vaccine.

— Residents in long-term care settings should receive a Pfizer booster vaccine

— People ages 50 to 64 with underlying medical conditions should receive a Pfizer booster vaccine.

— People ages 18 to 49 with underlying medical conditions may receive a Pfizer booster vaccine, depending on their individual benefits and risks.

— People ages 18 to 64 at increased risk for COVID-19 because of their occupational or residential setting may receive a Pfizer booster vaccine, based on their individual benefits and risks.

“With the Delta variant’s dominance as the circulating strain and cases of COVID-19 increasing significantly across the United States, a booster shot will help strengthen protection against severe disease in those populations who are at high risk for exposure to COVID-19 or the complications from severe disease,” according to a September 24 statement issued with CDC Director Rochelle Walensky’s endorsement of the updated recommendations.

If you initially received the Moderna or Johnson & Johnson series, the CDC says it will evaluate vaccine safety and effectiveness data swiftly and urgently to make additional booster recommendations.

Before the updated recommendations, a third COVID-19 vaccine was initially recommended for people on medications that suppress the immune system, such as certain rheumatology patients or those who’ve undergone a transplant, as well as for cancer survivors. That additional dose could raise antibody levels above the threshold needed for protection against COVID-19.

For the general public who aren’t any higher-risk categories, it’s still different: If you’re healthy and fully vaccinated against COVID-19, you’ll likely be able to get a booster shot — eventually. However, at issue is whether you really need that additional dose since the initial COVID-19 series already provides excellent protection.

With intense discussion among health experts and regulatory agencies such as the Food and Drug Administration and the CDC, booster recommendations for healthy people remain a moving target.

[See: What Are the Symptoms of Coronavirus?]

Who Is Eligible for a Booster?

On August 13, CDC Director Dr. Rochelle Walensky signed the recommendation for an additional dose of the COVID-19 vaccine for people with moderately to severely compromised immune systems. The recommendation from the CDC’s Advisory Committee on Immunization Practices (ACIP) encompasses people with immunosuppression who’ve already received an initial two-dose series of an mRNA — Pfizer or Moderna — vaccine.

For the Johnson & Johnson vaccine, evidence is still being evaluated and an additional dose is not yet recommended.

People may be immunosuppressed for various reasons, including:

— Active or recent cancer treatment.

— Solid organ or stem cell transplant.

HIV infection that’s advanced or untreated.

— Medications such as high-dose steroids, chemotherapy drugs, tumor-necrosis factor (TNF) blockers used to treat inflammatory conditions like rheumatoid arthritis.

— Medical conditions like chronic kidney disease that can weaken the immune system.

Booster vs. Third Dose

A booster shot causes “B cells” — immune systems cells that make antibodies — to multiply, raise antibody levels again and to produce an even stronger, more rapid response to future virus exposures.

Vaccine experts are emphasizing the difference between a third dose of the COVID-19 vaccine and a booster shot:

Booster shot. A healthy person who gets two doses of the mRNA vaccine develops a good antibody response and a high immunity level against COVID-19, explains Dr. Kathleen Neuzil, a professor in vaccinology and director of the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine. The booster is given to augment immunity that already exists, should it start to fade after a period of months or a year.

Third dose. An immunosuppressed person often fails to reach a basic, protective immune response after those initial two vaccine doses, Neuzil says. Fortunately, she adds, “After three doses, many more of them get there.”

There doesn’t appear to be a major downside to receiving the third dose, with reported side effects similar to the initial COVID-19 vaccine series, so far.

Immunosuppressed — Increased Need for Protection

In a comparison study from Israel involving nearly 500 participants — about half of whom had cancer and half who were healthy — those with cancer produced antibodies more slowly than other people after receiving the first dose of the Pfizer COVID-19 vaccine. However, the antibody rate improved for cancer patients after the second dose in the study, published July 8 in the journal JAMA Oncology.

Now, a good third-dose response is being seen in early studies:

— Administration of a third dose of the Pfizer vaccine “significantly improved the (ability to elicit an immune response) of the vaccine, with no cases of COVID-19 reported in any of the patients” for 101 patients with solid organ (kidney, liver, lung, heart or pancreas) transplants, in a study published August 12 in the New England Journal of Medicine.

— Similarly, a third dose of the Moderna vaccine produced an increased COVID-19 antibody response in another study of 120 solid-organ transplant patients. The response rate was 55% among those who received the additional dose, versus 18% who received a placebo injection in the comparison study.

[SEE: What to Say to Friends or Family Members Who Hesitate to Wear a Mask.]

Third-Dose Details for mRNA Vaccines

Right now, third dose have only been evaluated for the two mRNA COVID-19 vaccines available.

“A lot of people ask if the booster is going to be any different than the first two doses, and right now it’s not,” says Dr. Lisa Maragakis, senior director of infection prevention for the Johns Hopkins Health System and an associate professor of medicine at Johns Hopkins Medicine in Baltimore.

“It’s the same vaccine, although the companies are working on versions maybe for future boosters that will be targeted at certain variants, things like that,” Maragakis says. “But right now, boosters are an additional dose of the existing vaccine. ”

Ideally, the third COVID vaccine should be the same as the first two, according to ACIP recommendations. So, if you initially received two Pfizer doses, the third dose would optimally also be Pfizer — or a third Moderna dose if you initially received two Moderna doses. However, if that’s not feasible, using either of the mRNA vaccines is permitted for the third dose.

In terms of timing, the third dose should be given at least 28 days after the initial COVID-19 vaccine series is completed.

No Side Effects for Cancer Patients

“It’s a really important statement that the CDC has authorized the third dose, the emergency use authorization, in the setting of immunocompromised patients,” says Dr. David Cohn, chief medical officer at the Ohio State University Comprehensive Cancer Center, a professor in gynecologic oncology and a practicing gynecologic oncologist.

“Patients who are immunocompromised at baseline have a higher risk of contracting COVID because their immune systems are weakened,” Cohn says. “And if they were to get COVID, they’d have a higher rate of severe complications or death, and hospitalization from COVID. So, it’s a really important population to target.”

Cancer patients are eager to get the extra protection an additional dose could afford. “When we offered vaccination for our cancer patients, they were the first ones in line when their number got picked by the state of Ohio, and I’m sure it’s the same across the country,” Cohn says. “They were really excited to get back to some level of normalcy. And when the CDC authorized the third dose for this population, they were literally lined up at our door waiting to be vaccinated again.”

Third doses are going smoothly. “Anecdotally — because we vaccinated thousands of individuals already in our cancer hospital — we’ve not noticed any significant differences in the rates of severe reactions, which are extremely rare, or side effects at all from the third vaccine,” Cohn says.

Authorization for the extra dose took several steps. “The process is that the FDA provides their recommendation,” Cohn says. “The ACIP, the Advisory Committee on Immunization Practices at the CDC, then supports the recommendation to the CDC — who is the one that’s actually the approver for emergency use in the immunocompromised patients.”

Boosters for the General Population?

If you’re healthy and fully vaccinated, whether you should get a booster is less clear-cut. Although the Biden administration originally announced plans to start booster shots for the general public by late September, some health agencies like the World Health Organization are pushing back and questioning the need for boosters when COVID-19 protection from the initial series is still strong.

On Sept. 13, a viewpoint article published in The Lancet argued that with vaccine effectiveness averaging 95% even against the Delta variant in the general population, evidence to date may not justify the need for a booster for healthy people. The priority should be using vaccines to provide initial protection to the unvaccinated, which would do the most good by preventing the continuing evolution of COVID-19 variants, authors concluded.

In the most recent update on the CDC website, “Not immediately” is still the response to “When can I get a COVID-19 vaccine booster?”

Although the goal is for most people to start receiving the booster beginning in the fall, it’s subject to FDA authorization and recommendation by APIC, following an independent FDA evaluation of safety and effectiveness of the mRNA vaccines.

Once approved, individuals would be eligible to receive the COVID-19 booster in a specific number of months after their second dose of the Pfizer or Moderna vaccine.

[See: Fear, Courage, Grit: Meet More Than 50 ‘Hospital Heroes’ in Pictures.]

Staying Vigilant

If you get the third dose, continue to practice caution. “The safest guidance for those at the highest risk for contracting COVID or getting severe disease from COVID is still to be vaccinated and act unvaccinated,” Cohn says. “The kind of guidance has protected a lot of people. Although, if we lived in a society where everyone was vaccinated, I’d be telling a very different story.”

Although the discussion has moved to third doses and booster vaccinations, an ongoing issue is that some people are not vaccinated at all.

For people who are immunocompromised, and made the proactive effort to the third dose, “It’s also really important that their caregivers and close contacts are also vaccinated,” Cohn says. “Because that’s probably the biggest risk that they’re going to see. If they do everything to control their environment, not going out to the grocery store or putting themselves at risk — if their contacts and family members are unvaccinated, that still puts them at enormous risk for becoming infected with COVID-19.”

More from U.S. News

Ways to Boost Your Immune System

What to Say to Friends or Family Members Who Hesitate to Wear a Mask

Autoimmune Diseases That Can Be Fatal

Should I Get the COVID-19 Booster? originally appeared on

Update 09/24/21: This story was previously published at an earlier date and has been updated with new information.

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