CDC approves boosters for all vaccinated adults — and says it should be a priority for over-50s

• The CDC just endorsed booster shots for all adults.
• The agency approved an expert committee's verdict, that people under 50 may get boosted, but those over 50 really should.

Booster shots will become available to all vaccinated adults in the US this weekend.

The Centers for Disease Control and Prevention approved extra shots for everyone over the age of 18 late on Friday.

The green light came hours after a panel of independent doctors, nurses, and public health experts voted unanimously to recommend boosters for all vaccinated adults — though the recommendation is stronger for adults over age 50.

(Boosts are administered at least six months after Pfizer or Moderna vaccination, and at least two months after Johnson & Johnson.)

The committee's endorsement came after the Food and Drug Administration authorized Pfizer and Moderna boosters to all adults Friday morning.

CDC Director Dr. Rochelle Walensky approved these recommendations within hours, setting up a weekend of fresh booster shot appointments for adults of all ages around the country, just in time to ramp up community-wide protection against the coronavirus ahead of many indoor holiday gatherings.

Already, booster shots are being given out to all adults in New York City, California, Colorado, and New Mexico, skirting around the CDC's more stringent earlier guidelines, which stressed that boosters are most heartily needed in older adults.

But public health experts worry those more specific guidelines have created lots of confusion about who is eligible, and more simplicity is needed at this point in the pandemic.

"There was not a single state that voiced opposition to this move," Nirav Shah, president of the Association of State and Territorial Health Officials, said at the meeting.

"In pursuit of precision," he said, the CDC guidelines "create confusion" which means that many who are eligible to get boosters do not.

It's still true that older adults need boosters more urgently than younger ones do. But infectious disease experts have also stressed that the space between initial shots and boosts, at several months long, gives the body more time mount a more robust, and (hopefully) longer lasting immune response, giving people a stronger form of protection against the virus.

Dr. Anthony Fauci recently told Insider that even though "the vaccines absent the boost protect quite well," against severe outcomes, "the effect of boost is very, very favorable to preventing people from getting infected," because it drives the immune response even higher than the original shots.

CDC committee member Dr. Sarah Long, a pediatrician, said the new, more simplified booster recommendation "does make sense and it is reasonable" even if 18- to 39-year-olds don't really need boosters as much as older adults.

"The longer you wait to give the boost, the stronger the response will be," immunology expert Dr. James Hildreth, president of Meharry Medical College, recently told Insider. "More importantly, the antibodies affinities get higher the longer you wait, because there's an affinity maturation that happens."