Federal officials waited months before making all American adults eligible for a COVID-19 booster shot — meaning millions of Americans may not have the strongest possible protection as they head into holiday travel.
Why it matters: Critics say the confusing process undermined what has now become a critical effort to stave off another wave of the pandemic.
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Most vaccinated people, even without a booster, still have very strong protection against serious illness or death. But a third shot drastically increases people's defenses against even mild infections, which could in turn help reduce the virus' spread.
And some vulnerable vaccinated adults are at risk of serious breakthrough cases.
What they're saying: "We have a consensus. Boosters are very important in maintaining people's defenses against COVID. We need to get as many people vaccinated and boosted [as possible] as the winter sets in," David Kessler, the chief science officer of Biden's COVID response, said in an interview.
Context: Preliminary data released months ago suggested a significant decline in the vaccines' effectiveness at preventing infection, although they held up well against severe disease.
Based on that data, the Biden administration had hoped to begin allowing booster shots in September for any American adult who was at least eight months removed from their second dose.
The CDC and the FDA opted instead to only authorize boosters for seniors, people with high-risk medical conditions and people at high risk of infection, before opening them last week to everyone at least six months out from their initial shots.
In the meantime, red and blue states alike decided to ignore the CDC and open up booster eligibility on their own, and breakthrough infections have become increasingly common.
Millions of people who weren't technically eligible for boosters got them anyway, and a large portion of the most vulnerable patients still haven't gotten one.
Where it stands: Only 41% of vaccinated Americans 65 and older have received a booster shot, as have 20% of all vaccinated adults, per the CDC.
"Some of us were there several months ago. Some wanted more data. In the end, there's a convergence of opinions. It's the way an open scientific public health process should work," Kessler said.
Between the lines: The U.S. drug approval process — with its insistence on high-quality data and careful expert reviews — is the world's gold standard precisely because it moves deliberately. Regulators have been trying this whole time to figure out how to adapt that system to a fast-moving pandemic.
Some federal officials, as well as many outside experts, said there wasn't enough data to make a broad booster recommendation earlier this fall.
Early on, many public health experts also argued that it was unethical to give Americans a third shot while much of the rest of the world awaited their first shots.
Israel embraced boosters before the U.S. beginning over the summer, and its emerging data has been key to making the case that boosters are needed and can help bring surges under control. However, experts still don't know how long the enhanced protection they give will last.
What they're saying: "Some argued early on that the primary series was good enough and we should conserve doses for the world. What's emerging is that all people in the world are going to need to be boosted," a senior administration official said.
"Everyone has a different threshold for how much data they need in making a decision," the official added. "What made this different is that there's a pandemic underway, and many saw we were heading into a winter surge."
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