Health officials said Wednesday, Jan. 5, that they won’t change the definition of fully vaccinated to include COVID-19 booster shots even as the omicron variant — which seems to be able to transmit and evade vaccines more easily — spreads throughout the United States.

The decision comes as officials had been weighing a change to the definition given the evidence that booster doses increase a person’s protection against omicron. Some health experts had also pushed for the change.

But Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said during a White House COVID-19 Response Team briefing that a person will still be considered fully vaccinated if they’ve received their primary vaccine series: two doses of the Pfizer or Moderna vaccines or a single-dose of the Johnson & Johnson vaccine.

“That definition is not changing,” she said.

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A shift to ‘stay up to date’

Instead, Walensky said the CDC is now recommending that people “stay up to date” with any additional COVID-19 vaccine doses for which they are eligible. She said that messaging is “consistent with how public health has historically viewed or even talked about how we recommend vaccines.”

“We have now available how you can stay up to date with your COVID-19 vaccines based on what vaccine you have received and what age group you are in, and that is available now on the CDC website,” she said.


Everyone ages 5 and up should get a primary vaccination series, the CDC says.

Adults who initially received the Pfizer vaccine are eligible to get a booster shot five months after becoming fully vaccinated. Teens ages 16 and 17 who initially got the Pfizer vaccine can also receive a booster shot after five months but are only eligible for a Pfizer booster.

Adults who initially got the Moderna vaccine are eligible for a booster after six months, and adults who initially received the Johnson & Johnson vaccine are eligible for a booster after two months, according to the CDC.

On Tuesday, Jan. 4, the CDC also recommended that “moderately or severely immunocompromised” children ages 5 to 11 get an additional dose of the vaccine 28 days after their second shot.

Officials were asked during the Jan. 5 briefing whether people who aren’t up to date on their COVID-19 vaccines should expect travel or employment restrictions in the future. But White House COVID-⁠19 Response Coordinator Jeff Zients said there are no plans for those requirements to change.

“I do think it’s really important to recognize the vast majority of hospitalizations and deaths are among the unvaccinated Americans, and completing the primary vaccination series is clearly a critical step to prevent severe outcomes — with boosters, as Dr. Walensky said, giving the highest level of protection, Zients said.”


Vaccines and the omicron variant

Data has suggested that an initial COVID-19 vaccination series alone offers less protection against the omicron variant compared with previous coronavirus strains.

But data has shown that booster doses of the Pfizer and Moderna vaccines significantly increase antibody levels against the variant, McClatchy News reported. Most experts recommend receiving a Pfizer or Moderna booster as the Johnson & Johnson booster seems to offer the smallest increase in antibody levels.

The evidence of the importance of boosters against omicron is what led some experts to urge that boosters be required for a person to be considered fully vaccinated.

Dr. Anthony Fauci, the nation’s top infectious disease expert, told CNN in December that a change to the fully vaccinated definition was “on the table and open for discussion,” adding that there’s “no doubt that optimum vaccination is with a booster.”