If you’ve received a two-dose course of the Moderna or Pfizer COVID vaccines, or a one-and-done Johnson & Johnson shot, you’re considered by health officials to be fully vaccinated against the coronavirus.
For now.
But that could change as eligibility for booster shots continues to expand. Last week, COVID boosters were approved for Moderna recipients and all who got the Johnson & Johnson vaccine, and everyone can now choose their own brand of booster shot.
Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said at a news conference Friday that the agency “may need to update our definition of ‘fully vaccinated’ in the future” as boosters are becoming more widely available.
When would that happen, and what would it look like? Walensky had no further details, as she and other health experts acknowledge that the situation is evolving.
“We’re doing an experiment in real time,” said Warner Greene, a virologist and senior investigator at the Gladstone Institutes in San Francisco. “We don’t know how to optimally use the vaccines yet. What we do know is that two shots are not preventing infections as efficiently after six months.”
Here’s what we know so far about what changing the definition of “fully vaccinated” could entail.
What is the current definition of a fully vaccinated person?
According to the CDC, a person is considered fully vaccinated against COVID-19 if it’s been at least two weeks since their second dose in a two-dose series (Pfizer or Moderna), or two weeks since a single-dose vaccine (Johnson & Johnson).
Am I still considered fully vaccinated even if I am eligible for a booster dose?
Yes. If you’re in a group approved for a booster but haven’t yet received one, you currently meet the definition of fully vaccinated.
However, experts advise those eligible to go ahead with another shot.
UCSF infectious disease expert Peter Chin-Hong said the data shows that “the most compelling case for a booster shot” is people 65 and older and “certainly” immunocompromised individuals.
Those not eligible yet shouldn’t worry, he said — for them, boosters are “a good idea at some point, but not an emergency.”
“Without a booster, the vaccines for most people in the U.S. are still holding up exceptionally well in protecting against serious disease hospitalization and death - arguably the outcomes we care most about,” Chin-Hong said.
What is the current booster eligibility?
Specific groups who received the Pfizer or Moderna vaccine are eligible for a booster at least six months after completing the initial vaccine series. The groups are people 65 years or older, and anyone 18 or older who lives in a long-term care facility, has underlying medical conditions or works or lives in a high-risk setting.
People 18 or older who were vaccinated with the Johnson & Johnson vaccine at least two months ago are also eligible for a booster shot.
What does a potential change in the definition of full vaccination mean?
Robert Siegel, a professor of microbiology and immunology at Stanford University, said the term “fully vaccinated” is a policy concept, not an immunological one.
“Policies change and the designation of who is ‘fully vaccinated’ will continue to change,” he wrote in an email. “Ideally, these changes will be based on new data on the durability or diminution of the immune response over time.”
Greene predicted that while younger individuals still appear to have strong protection from the current vaccination regimen, he predicts they will likely need boosters down the line.
“It’s becoming increasingly clear that vaccination protection wanes,” he said. “It will probably still keep people out of the hospital and keep them from dying, but in terms of preventing infections, it’s not as effective.”
He said that, ideally, vaccines will prevent the virus from spreading and new variants from emerging.
What would determine the definition change?
For the definition of “fully vaccinated” to change to include boosters, everyone would first need to have access to booster shots, not just certain groups. The rules and timing should also be simplified, Chin-Hong said.
Changing the definition would require health agencies and experts to keep following breakthrough infections and their frequency, according to Greene.
“The severity is what really will make physicians and scientists take notice, if fully vaccinated people begin getting hospitalized at a high number, require intubation and there is an increased death rate,” he said. “That is a clear sign the vaccine has lost effectiveness.”
A real world CDC study published in late September found that the Pfizer vaccine was 88% effective at preventing hospitalizations from COVID, Moderna was 93% and Johnson & Johnson was 71%.
Chin-Hong echoed that assessment and said “there should be compelling evidence” that not getting a booster is resulting in a decline in protection against serious disease, hospitalizations and deaths in all age groups and vaccine brands.
