- Official guidance on booster shots is still to come.
- The CDC and FDA say that boosters, when authorized, should be for Americans over 65 and those with certain health conditions.
- New data shows that a booster increases efficacy of the single-dose Johnson & Johnson vaccine, but as with the Pfizer and Moderna vaccines, these boosters are not yet authorized.
News about COVID-19 booster shots has been a little confusing lately. On August 18, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) announced that all Americans who received the two-dose mRNA COVID-19 vaccines should get booster shots eight months after receiving their second dose. That included those who received either the Pfizer-BioNTech or Moderna vaccines, and they were told boosters would be available in September.
But at the time, neither the CDC’s Advisory Committee on Immunization Practices (ACIP) nor the FDA officially authorized booster shots for Americans aged 12 and up. After meeting last week, an advisory panel to the FDA voted that only Americans who are 65 and up, or who have certain underlying health conditions, should get booster shots at this time. The reason, the panel members said, is that there is not yet enough evidence to recommend boosters for younger, healthier people. “The FDA has not formally acted to issue an emergency use authorization,” points out William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. Meaning, nothing is official—for anyone—just yet.
The ACIP is scheduled to meet on the topic on September 22 and vote on September 23—but they won’t be able to vote until there is a formal action from the FDA, Dr. Schaffner explains. “It’s confusing for people and it’s a confusing process,” he says.
On Sunday, Anthony Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases, urged people not to get booster shots of the COVID-19 vaccine before they’re eligible despite the original message to get a booster shot eight months after receiving a second dose of an mRNA vaccine. “I think people are not understanding the difference of planning for something and actually what element of that, what proportion of it, you’re actually going to roll out,” he said on NBC’s Meet the Press. “And that’s exactly what happened.”
Much of the attention has been on booster shots for the mRNA vaccines—Pfizer and Moderna—but the joint statement previously issued by the CDC and FDA also said that people who received the single-dose Johnson & Johnson vaccine will likely also need an additional shot, pending the results of the company’s two-dose clinical trial. Now, that data has been released.
Johnson & Johnson announced on Tuesday that a phase 3 clinical trial found that two doses of its vaccine gave patients 94% efficacy against mild to severe forms of COVID-19, and 100% efficacy against severe forms of the virus. Worth noting: This doesn’t mean that you should seek out a booster dose of the Johnson & Johnson vaccine yet—government agencies haven’t yet reviewed the data or authorized those boosters yet.
So when will you actually be able to get one? And how do they work? We asked doctors to explain why booster doses may be necessary in the future—plus why you should get your first dose of the vaccine as soon as possible if you aren’t yet vaccinated.
Back up: How do booster shots for vaccines work?
“For some vaccines, after a while, immunity begins to wear off,” the CDC explains. “At that point, a ‘booster’ dose is needed to bring immunity levels back up.” Booster shots are extra doses of a vaccine administered sometime after an initial dosage has been received, re-upping your body’s immune response.
Some boosters are recommended very infrequently, like one for tetanus, which should be received every decade. Others, like the annual flu vaccine, are more frequent, due to factors like changing pathogens and waning immunity. Different types of flu virus circulate each year, making an annual shot necessary to protect against the most dominant strains each flu season.
SARS-CoV-2, the virus that causes COVID-19, is also mutating, and the variant of most concern is currently Delta, which was first detected in India last December. So far, all of the available COVID-19 vaccines, especially the mRNA ones, appear to offer adequate protection from the Delta variant.
Will you need a COVID-19 vaccine booster shot for full protection?
“At some point, most of us will need a booster,” says Dr. Schaffner. “That happens with a lot of adult immunizations, including the flu vaccine.”
However, COVID-19 vaccines have only been widely available since December 2020 at the earliest, and data is still being collected on how long protection from the vaccines will last.
“There has been a sense that the administration has been very impressed with the data from Israel, which would indicate that immunity is waning,” Dr. Schaffner says. The country has seen preliminary success in giving some of its residents a third dose, which may have provided inspiration for the booster approval by the CDC and the FDA.
There are different strategies to deal with variants, which are now driving the country’s surge in cases, explains infectious disease expert Amesh A. Adalja, M.D., senior scholar at the Johns Hopkins Center for Health Security. “One is to reformulate the vaccine, and the other is to add another booster with the same formulation,” he explains. Creating a booster could increase antibodies and T cells (a type of white blood cell that’s an essential part of your immune system) enough to help tackle variants of the original, dominant SARS-CoV-2 strain. “The COVID-19 vaccine may eventually become like the annual flu vaccine,” he says.
Why might boosters be necessary after eight months?
“The available data make very clear that protection against SARS-CoV-2 infection begins to decrease over time following the initial doses of vaccination, and in association with the dominance of the Delta variant, we are starting to see evidence of reduced protection against mild and moderate disease,” the CDC and FDA said in a joint statement.
“Based on our latest assessment, the current protection against severe disease, hospitalization, and death could diminish in the months ahead, especially among those who are at higher risk or were vaccinated during the earlier phases of the vaccination rollout,” the announcement continues. “For that reason, we conclude that a booster shot will be needed to maximize vaccine-induced protection and prolong its durability.”
For example, a small study of public health data from Israel released in late July estimated that the Pfizer-BioNTech shot was 39% effective at preventing people from COVID-19 infection in June and early July, compared with 95% from January to early April. That said, the vaccine was still more than 90% effective in preventing severe disease in people in June and July.
“It is true that if you look at antibody levels produced by the vaccine, by eight months, they’re starting to wane,” Dr. Schaffner says. “But antibody levels are an imprecise indicator of protection, and other aspects of protection continue to go on.” (This includes those aforementioned T cells.)
That said, there have been signs that the protection is still better than expected. In a June 2021 study published in the journal Nature, researchers found that the mRNA vaccines trigger an immune response that may offer years-long protection against SARS-CoV-2.
Bottom line: More clarity on booster shots is coming.
There are still many people in the U.S. who need to get even their first dose of the COVID-19 vaccine, although there is plenty of supply available. “The priority still should be getting people vaccinated with the original vaccine, which does have an impact on all of the variants when it comes to what matters—serious illness, hospitalization, and death,” Dr. Adalja says.
As for booster shots right now, Dr. Schaffner recommends sitting tight. “At the moment, hang out—we will get some clarification soon,” he says, before stressing that the FDA will have to authorize booster shots for each vaccine separately. “The first recommendation will only have to do with Pfizer booster shots, then will come Moderna, and then Johnson & Johnson,” he says.
As for when you’ll need a booster shot? It’s unknown at this point. “It’s unclear that everyone will need boosters but it is a possibility in the future—it would be something based on erosion of protection against severe disease, which isn’t something happening in the general population yet,” Dr. Adalja says.
This article is accurate as of press time. However, as the COVID-19 pandemic rapidly evolves and the scientific community’s understanding of the novel coronavirus develops, some of the information may have changed since it was last updated. While we aim to keep all of our stories up to date, please visit online resources provided by the CDC, WHO, and your local public health department to stay informed on the latest news. Always talk to your doctor for professional medical advice.
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