COVID-19 vaccinations are now available in America for over one year. But the shots weren’t designed to prevent infection with SARS-CoV-2, and the immunity generated by the vaccines wanes, so the virus continues to mutate and become even more transmissible—and infect even the vaccinated. A booster dose can help increase your immunity. Last year, public health officials issued an initial booster shot to most people. But as new variants of the virus continue to emerge, it’s time to consider another booster dose for the wider population. The second shot is already recommended to certain individuals at risk for COVID-19, who may benefit from enhanced protection by this booster.
Experts, however, aren’t comfortable with a strategy of simply adding booster after booster of the same vaccine. They have started studies to determine if the existing vaccines are still the most effective. Here’s what we know so far.
Can you get another booster shot?
The majority of adults in America are up-to date on their COVID-19 vaccines. They must be vaccinated and then receive a booster dose several months later. For either Pfizer-BioNTech’s or Moderna’s shots, that entails two primary doses and a booster; if you were immunized with Johnson&Johnson-Janssen’s shot, it’s one initial dose and a booster.
Children aged 12 to 17 years old can get boosted, but only with the Pfizer-BioNtech shot; Moderna’s and Johnson&Johnson’s boosters have not been authorized yet for this age group.
Some people (e.g. those older than 50 years and patients with chronic conditions that affect their immune systems) may need a second dose of booster. This is because they are more likely to die from severe COVID-19. Based in part on Israel data, that found adding another booster in January to people over 60 or health care workers decreased the risk of dying from severe COVID-19, this recommendation is partly supported by Israel’s research.
Experts reviewed research that looked into whether adding another dose of booster could be beneficial at a Food and Drug Administration meeting. For example, they looked at research showing that the immunity generated by the first booster wanes after a few months—studies from Israel show that rates of severe disease among boosted people are starting to rise, although they still remain lower than rates among non-boosted people. Lab-based research from the U.S. also confirmed that virus-fighting antibody levels decrease after several months. This is approximately six times as fast.
Additionally, any incremental benefit of a second booster has to be weighed against the potential side effects, which include inflammation of heart tissue, especially for younger people receiving the Pfizer-BioNTech or Moderna vaccines, and the risk of blood clots for people getting the J&J shot. That means continuing to boost every four months or so with the same vaccines isn’t a sustainable way to confront COVID-19, especially if the virus continues to mutate.
After considering all of the studies available so far, the committee concluded that there aren’t yet enough data to support recommending a second booster for the general population. While a second booster can raise the levels of a person’s antibodies against COVID-19, and protect them from more serious disease, that protection doesn’t last as long as health officials would like. So for the vast majority of the U.S. population, that second booster isn’t necessary—at least not yet.
If I’m authorized, when should I get a second booster?
The only people eligible for a second booster are those over 50 years old and people with compromised immune systems. You can receive an additional booster dose if your immune system has been compromised. This means that you will be eligible for a fifth booster. A second booster can be obtained for those who are immunecompromised, and have had the Moderna vaccine given as your first vaccination.
A second booster won’t necessarily protect you from getting infected with SARS-CoV-2, but if you do get infected, it can reduce your chance of getting severely ill and even going to the hospital for COVID-19-related symptoms.
What time will it be possible for the remainder of the population to receive a second booster.
When it comes to the rest of the population, the situation isn’t as clear. Booster shots can increase antibody levels, which is undisputed. It’s also well-established that antibodies are an important, although not the only, contributor to a strong immune defense against SARS-CoV-2. Studies show that each dose of the currently-approved COVID-19 vaccines build up a person’s T-cell response—a group of immune system cells which tend to remember specific viral infections and remain at the ready the next time they encounter them. Researchers have found that the T-cells in fact are what protect and boost people who are vaccinated. Understanding how well a second booster might continue to enhance this T-cell response could help health officials decide if that additional dose is necessary for people who aren’t at highest risk of severe disease—the T-cell response is, indeed, currently under scientific investigation.
Scientists are currently trying to figure out whether vaccines can induce an immune reaction strong enough to protect against infection, as well as how long it lasts and whether this vaccine will be the most effective. At the moment, the shots being used as a second booster dose are the same as the original vaccine, and don’t seem to be pushing protective antibody levels any higher than they were after the first booster.
What should I do?
Boosters have always included a dose of the original vaccine. Omicron subtype BA.2 is now the most recent infective variant. Health professionals are looking at changing COVID-19 to prevent future infections. It’s similar to the annual flu shot, where they swap out influenza strains.
Drug manufacturers responsible for some of the best vaccines have developed new products and are currently testing them. To find a booster that generates a stronger and longer lasting immune response, these companies also test combinations of the shots. But the results from these studies won’t be available until summer at the earliest, so it’s unlikely health officials will recommend additional boosters for the bulk of the U.S. population until after those results are analyzed.
Because of the higher chance that they will get serious illness if infected even though they’ve been vaccinated, certain groups won’t be eligible for the second booster. For the rest of us who are vaccinated and boosted, making individual decisions about continuing to wear masks in crowded indoor settings, and avoiding environments where we might be in close contact with a lot of people, continue to be the best ways to limit our exposure and risk of COVID-19—at least until more data become available.
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