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Second Booster Shots: Who Should Get One and When?

Adults 50 and older have been cleared to get another dose of a COVID-19 vaccine

doctor placing a bandage on a woman's arm after administering the coronavirus vaccine

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Adults 50 and older can now roll up their sleeves for a second COVID-19 booster, as can younger individuals with certain immune-compromising conditions.

The Food and Drug Administration (FDA) authorized the extra shot March 29, and the Centers for Disease Control and Prevention (CDC) agreed to add it to its coronavirus vaccine recommendations. But health officials stopped short of urging everyone in the eligible population to run out and get it, leaving many to wonder if they should.

“There’s not a simple answer to this,” says William Moss, M.D., executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health. Other experts agree: A few factors can shape your decision.

Here’s what to think about when thinking about a second booster shot.

Who is eligible for a second booster?

  • Adults 50 and older can get a second booster dose of either the Pfizer-BioNTech or the Moderna vaccine at least four months after their first booster.
  • Individuals 12 and older who have certain immunocompromising conditions can get a second Pfizer booster at least four months after their first booster.
  • People 18 and older who have certain immunocompromising conditions can get a second Moderna booster at least four months after their first booster.
  • Adults who received a primary vaccine and booster dose of Johnson & Johnson’s (Janssen) vaccine at least four months ago can get a second booster dose using an mRNA COVID-19 vaccine.

Source: FDA, CDC

What’s your individual risk?

The biggest risk factor for getting a severe case of COVID-19 is age, says Carlos del Rio, M.D., professor of medicine in the Division of Infectious Diseases at Emory University School of Medicine. This is largely because the immune system starts to lose some of its oomph as one gets older.

Data from the CDC shows that Americans 85 and older account for the largest share of deaths from COVID-19, followed by 75- to 84-year-olds and 65- to 74-year-olds. All together, people 50-plus account for more than 93 percent of the roughly 1 million deaths from COVID-19 in the U.S.

But underlying health conditions like diabetes, obesity and heart disease can also complicate a coronavirus infection. So it’s important to assess your risk based on these key factors. (Think about it this way: A 50-year-old who doesn’t have any health conditions is in a different risk category than an 85-year-old who is managing several.)

The FDA’s decision to authorize the second booster was based on data from Israel that suggests a second booster dose given at least four months after the first booster can reduce the risk of hospitalization and death in adults 60 and older and other high-risk individuals. The reason U.S. health officials decided to extend the eligible age range to 50 is because “we know that people in the age range from about 50 to 65, about a third of them have significant medical comorbidities,” meaning the presence of two or more underlying health conditions, Peter Marks, M.D., director of the FDA’s Center for Biologics Evaluation and Research, explained in a news briefing. “So by choosing age 50 and up … we felt like we would capture the population that might most benefit from this fourth booster dose.”

Ashley Drews, M.D., an infectious disease physician and epidemiologist at Houston Methodist, says immunocompromised folks and people who are 65 and older (some experts suggest 60 and older) should go ahead and get the second booster now. The same goes for anyone in their 50s who has an underlying health condition that puts them at high risk for severe illness. “But if you are 50 to 60 and don’t have any underlying health conditions that place you at increased risk of severe COVID, then it’s not as urgent for you to get the second booster right now,” Drews says.


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Del Rio adds that younger, healthier individuals in the eligible population can get the second booster if they want to, “but for the time being, it’s not going to help you that much.” While some protection afforded by the vaccines wanes, the primary series and first booster “continue to hold incredibly well against severe disease and death” in these less vulnerable populations, he says.

Another factor to consider when weighing your risk: recent infection. Like millions of Americans, Moss — who is 64, boosted and “otherwise healthy” — had COVID-19 during the winter omicron surge. “In some ways, that infection is a booster dose to your immune system,” he says. So right now, he doesn’t feel “an urgency to get a second booster dose.”

Health conditions that increase risk of severe COVID

Common health conditions that increase a person’s risk for getting seriously ill from COVID-19 include:

  • Cancer
  • Chronic kidney disease
  • Chronic lung diseases, including moderate to severe asthma
  • Dementia or other neurological conditions
  • Diabetes (type 1 or type 2)
  • Heart conditions, including heart failure and coronary artery disease
  • Overweight and obesity

This list is not exhaustive; you can find a full list of conditions here.

Source: CDC

What’s happening in your community?

Reported cases of COVID-19 have largely leveled off and are approaching pandemic lows, which means risk of exposure has also decreased in many areas of the country, Moss points out. But we all know that could change. Several countries in Europe just experienced a surge in cases fueled by the omicron BA.2 subvariant, which recently became the dominant strain of the coronavirus in the U.S. Experts say BA.2 could cause a bump in cases here — some areas are already seeing an uptick — but they are not anticipating a wave as cataclysmic as the one caused by omicron.

If numbers start to tick up again, “then that kind of changes the calculus,” Moss says. His advice: Keep an eye on what’s happening in your community. (You can track community transmission rates on the CDC’s website and find guidance for your area.) If transmission levels start shooting up and you haven’t had the second booster, “then that may make the decision to get the second booster earlier rather than later,” Moss says.

This advice holds true for travel destinations, too. If your spring or summer plans include trips to cities or countries battling high levels of the virus, aim to have your second booster several weeks before departure to ensure your antibody levels are at their highest. Antibodies are proteins produced by the immune system that help to fight off an infection and keep you from getting sick.

“You don’t want to time it too close to your travel or you won’t have realized that full benefit,” Drews says. “But again, if you’re in that high-risk population — if you’re 65 or older, or you’re a transplant recipient, or you have diabetes — I would go ahead to get it now. I wouldn’t wait.”

And while you’re examining transmission trends in your area, think too about your access to testing and treatments, which can influence the outcomes of an infection. Thousands of pharmacies and clinics throughout the U.S. can test people who think they might have COVID-19 and, for positive patients, prescribe treatments on the spot. You can find if one of these so-called test-to-treat locations is near you on COVID.gov.

In addition to the vaccines, “we need to be able to use other tools in our toolbox,” Moss says.

“The major determinants are age and then your underlying health conditions. And the more your personal risk is of severe COVID, then the sooner you want to go ahead and get that second booster.”

Ashley Drews, M.D., Houston Methodist

Are there any downsides?  

There aren’t any known downsides to getting another booster, even if you don’t need one, experts say. The vaccines have a solid safety record, and serious side effects are rare.

The risk of myocarditis — one of these uncommon side effects — in the 50-plus age range “is really considered to be minimal,” the FDA’s Marks said. “The side effect profile that was looked at in a million individuals who had received additional doses in Israel looks very favorable in this age range.” That said, you should plan for some possible, albeit temporary, side effects after the shot. Fatigue, fever, headache, muscle pain, chills and nausea are all common symptoms reported after the COVID-19 vaccines and other vaccines.

But there also don’t seem to be any benefits to an added boost for people who don’t need one — again, we’re talking about younger individuals who don’t have any health issues — especially when it comes to building the longer-lasting cellular immunity that helps to protect the body from severe disease.

“Individuals will always get an increase in their antibody levels after a booster dose. But how critical that is isn’t clear,” Moss says. “It comes back to: What is really our goal with vaccinations? Is our goal to just try to prevent all infections, which is almost an impossible goal for a vaccine, or is it to prevent severe disease and hospitalizations and death, which is a much more reasonable goal? And I think we’ve probably reached that in most individuals with three doses.”

The FDA has a meeting April 6 to discuss the future of boosters, including whether more will be needed for a broader swath of the population and how often. Health officials will also discuss what those vaccines might look like. It may be that in the next several months to a year, we have more options for boosters, Moss says, like variant-specific vaccines or nasal vaccines that provide local immunity. Scientists are also working on developing a vaccine that could work against multiple coronaviruses. 

It’s also possible, “particularly in otherwise healthy, younger adults, that they may not need an annual booster,” Moss says, though this depends on the course of the pandemic and any variants that may emerge. “Maybe that annual booster is more for the most vulnerable.”

What’s the takeaway?

The key message is to evaluate your risks, and if you have any questions, talk to your doctor.

“Again, the major determinants are age and then your underlying health conditions,” Drews says. “And the more your personal risk is of severe COVID, then the sooner you want to go ahead and get that second booster.”

And don’t forget about other tools that can help to prevent severe illness: High-quality masks can help keep an infection from happening in the first place, and if you do get COVID-19, a menu of treatments can help to prevent the disease from progressing.

“I think the other thing that’s important is, if you haven’t been vaccinated or boosted, you should. Because I’m more concerned about the millions still who have not been vaccinated, or the millions over 65 who have yet to receive their first boost. That, to me, should be a focus,” del Rio says.

Rachel Nania writes about health care and health policy for AARP. Previously, she was a reporter and editor for WTOP Radio in Washington, D.C. A recipient of a Gracie Award and a regional Edward R. Murrow Award, she also participated in a dementia fellowship with the National Press Foundation.