Earlier in the COVID-19 pandemic, as signs of waning immunity and changes in the virus prompted the rollout of additional doses of vaccine, health authorities took to urging Americans to seek out "booster" shots to improve their protection against the virus.

Now, with an updated vaccine formula rolling out for the fall, officials are changing that message to move away from the word "booster."

Instead, doctors and health departments are now working on getting used to calling this year's newly recommended shots the "2023-2024 COVID-19 vaccine" or simply the "updated COVID-19 vaccine." 

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Virtually all Americans ages 6 months and older are now recommended to get one dose of these updated shots from Moderna or Pfizer, regardless of what vaccines they have or have not received before.

"Bye bye, booster. We are no longer giving boosters, and it's going to be very difficult to stop using that word because that word has become pervasive," Dr. Keipp Talbot, a member of the Centers for Disease Control and Prevention's committee of vaccine advisers, said.

Talbot was speaking Thursday at a webinar hosted by the Infectious Diseases Society of America titled, in part, "COVID-19 New Booster Vaccine & Variants Update."

"We are beginning to think of COVID like influenza. Influenza changes each year, and we give a new vaccine for each year. We don't 'boost' each year," said Talbot.

No more "primary series"

The change in terminology stems from a proposal, first backed by a panel of the Food and Drug Administration's outside advisers back in January, to dramatically simplify the schedule of authorized and approved COVID-19 vaccines.

Most Americans originally received a "primary series" of shots that were targeted at the original strain of the virus early in the pandemic. Then, a mix of "booster" doses were offered — some targeted at more recent variants — with varying guidelines depending on a person's age and what shots they previously received. 

That made it difficult for some people and their doctors to figure out whether they were "up to date" on their shots. Meanwhile, still-unvaccinated Americans who wanted to get caught up faced a need to get through the "primary series" doses of the old formula of vaccines before they could qualify for the latest versions of the shots.

The FDA took steps towards simplifying the regimen in April, phasing out the original versions of the vaccine and removing the "primary series" versus "booster" distinction for most people.

Later, when the FDA announced it was authorizing and approving the latest formulation of the vaccines on Monday, targeted for the XBB.1.5 strain of the virus, the agency's press release made no mention of "booster" doses.

"To clarify, these vaccines would not be considered 'boosters' per se. These vaccines, as previously announced, would be updated with a new formulation for the 2023-2024 fall and winter seasons," an FDA spokesperson said Thursday in an email.

Other federal authorities have hewed closely to the new terminology. 

Statements from the White House and the Department of Health and Human Services also never used the word "booster" when touting new availability of these latest shots. 

CDC polling on the new shots asked Americans simply if they were open to getting the "new, updated COVID-19 vaccine."

But the word "booster" still remains on many other official pages, including the United Kingdom's "autumn vaccine booster" campaign overseas and press releases within the U.S. from some state and local health departments.

"It's going to be difficult to start changing that terminology, but it is no longer a booster. It is now the current vaccine for the year," said Talbot.

In:
• COVID-19 Vaccine
• COVID-19

Alexander Tin

CBS News reporter covering public health and the pandemic.