Will We Need a COVID-19 Vaccine Booster Shot?
Share on Pinterest- The CEOs of some pharmaceutical companies say COVID-19 vaccination booster shots may be needed as early as this fall to bolster immunity against the disease.
- Experts say it’s too early to tell if and when those booster shots will be needed.
- Booster shots are not uncommon. They’re used for the Tdap (tetanus, diphtheria, pertussis) vaccine, among others.
The vaccines being used in the United States and other parts of the world are safe and effective in preventing severe cases of COVID-19.
How long that protection lasts is still not fully understood — both the virus and the vaccines against it are relatively new.
Breakthrough infections — those occurring in people who have been vaccinated against COVID-19 — are happening. So far, though, they are largely occurring without major problems. Most people are asymptomatic, and their cases are discovered only during routine testing.
As variants of the novel coronavirus continue to spread and mutate, researchers are monitoring how the vaccines perform and whether booster shots will be needed to maintain meaningful immunity.
Right now, experts say it’s too early to speculate whether we’ll need booster shots like some routine vaccines.
Dr. Amesh Adalja, a senior scholar at Johns Hopkins Center for Health Security in Baltimore, says it’s premature to predict whether COVID-19 boosters will be needed and, if so, at what intervals.
“To me, the threshold for boosters would be to see fully vaccinated individuals getting breakthrough infection severe enough to land them in the hospital,” Adalja told Healthline. “We have not crossed that threshold.”
However, the CEO of the companies whose COVID-19 vaccines are being distributed in the United States say their shots may need to be given annually, like a flu shot. They told Axios those boosters could come as early as September.
Data shows Moderna and Pfizer vaccines, which both use the same mRNA technology to create immunity against the novel coronavirus, remain effective after 6 months. Still, Pfizer officials in February said they are testing a booster shot up to a year after a person receives their first two doses.
AstraZeneca’s vaccine — which hasn’t received approval to be used in the United States — has been tested with a booster or a second shot after 12 weeks. Still, it doesn’t appear to offer any more meaningful protection than doses given closer together.
An international team of researchers published a paper in the journal Nature Medicine in January that looked at what was next for COVID-19 vaccinations beyond their phase 3 trials.
“Additional booster doses might be necessary to extend the duration of protection,” they wrote. “We do not know whether primary series and booster doses can or should be different.”
Dr. Anthony Fauci, the United States’ leading voice on infectious diseases, told a Senate subcommittee last week that he doesn’t anticipate that the durability of the COVID-19 vaccine protection “is going to be infinite.”
“It’s just not,” he said. “So I would imagine we will need, at some time, a booster.”
When that booster is needed, Fauci said, remains to be seen. Researchers are continuing to see when the current vaccines’ protections begin to fade.
The Centers for Disease Control and Prevention (CDC) recommends boosters for other common vaccines.
For example, a booster for the vaccine that protects against tetanus, diphtheria, pertussis, or Tdap, is recommended every 10 years. People who travel in countries with high levels of hepatitis A are advised to get a booster shot 12 months after their first doses.
A team of Australian researchers published research in March that used predictive modeling to see how well COVID-19 vaccine protection lasted by examining titer or the concentration of protective antibodies. They found the decay of protection 250 days after immunization predicted a “significant loss” in protection, “although protection from severe disease should be largely retained.”
And that’s the whole point of vaccines: To protect from serious infection that could result in hospitalization or even death.
Dr. Stephen Russell, CEO and co-founder of Imanis Life Sciences — a Rochester, Minnesota, company that makes COVID-19 antibody tests — says it’s possible a fully vaccinated person could remain protected for more than a year. That protection could also drop off as quickly as 3 months.
“The appropriate timing of booster shots is therefore very difficult to determine without specific information about the peak neutralizing antibody titer and its rate of fall in a given individual,” he said.
Russell also says the Pfizer and Moderna vaccines appear to generate the highest neutralizing antibody titers, followed by the AstraZeneca and the Johnson & Johnson vaccines. But, he said, different vaccines work differently, and it’s still possible that a vaccine might be developed for COVID-19 that gives lasting immunity.
“The common childhood vaccines such as measles, mumps, and rubella that most of us have had typically result in lifelong immunity,” Russell said, “but they use live replicating viruses, which may persist much longer than mRNA vaccines and are therefore able to drive a better, more lasting immune response.”
For now, there’s not enough evidence to suggest that the current vaccines can’t keep up with the current versions of the novel coronavirus.
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