President BidenJoe BidenChina eyes military base on Africa's Atlantic coast: report Biden orders flags be flown at half-staff through Dec. 9 to honor Dole Biden heading to Kansas City to promote infrastructure package MORE's chief medical adviser Anthony FauciAnthony FauciMurthy says travel restrictions are 'temporary measures' Fauci calls Ron Johnson's AIDS comment 'preposterous': 'I don't have any clue of what he's talking about' Fauci: US 'hopefully' will lift African countries travel ban in 'reasonable period of time' MORE on Thursday night urged those 18 and older to get a booster shot for added protection against COVID-19.
Fauci said on MSNBC's "All in with Chris Hayes" that he has believed "for some time now" that boosters are effective and should be recommended for all adults in the U.S. who received their vaccine six months ago or longer.
"If you're 18 or older, go get boosted," Fauci said.
The top infectious diseases expert said that "vaccine efficacy wanes over several months," but reiterated that Pfizer's shot is "still a very, very effective vaccine."
Fauci also pointed to studies released in Israel and the U.K. that he said showed the booster "dramatically increases" protection against infection and hospitalization, noting that the Israeli studied also showed a boost in protection against death from the virus.
"There's no doubt about it. The data are very clear," said Fauci.
The Food and Drug Administration (FDA) is expected to authorize booster shots for all adults on Friday. Fauci said he hopes the move will ensure there is "no more ambiguity" about who is eligible for a booster dose.
He explained that getting a booster was of particular importance now as "we are entering the winter season; the weather will be colder, people will be indoors, they're circulating virus around, we're seeing an uptick in some of the cases right now."
Fauci also stressed the need to get unvaccinated people inoculated as quickly as possible.
The Centers for Disease Control and Prevention (CDC) independent committee of vaccine experts is scheduled to meet Friday to go over the data on booster shots.
Should both the FDA and the CDC approve moving forward with the authorization, any American adult who received a second dose of the vaccine six or more months ago will be eligible to get a booster dose this weekend.