A top U.S. health official on Sept. 6 said that COVID-19 vaccines could turn into a yearly shot, similar to the annual recommended influenza vaccine.
"However, some particularly vulnerable groups may continue to need more frequent vaccination against COVID-19," Fauci added.
Fauci's agency does not clear vaccines or deal with vaccination recommendations, but he has often been the government's most visible health official during the COVID-19 pandemic and previewed key shifts in policy.
And another key official, Dr. Ashish Jha, the White House COVID-19 response coordinator, also spoke of yearly vaccinations.
Barring any major differences in new variants, "for a large majority of Americans, we are moving to a point where a single annual COVID shot should provide a high degree of protection against serious illness all year," Jha claimed during the briefing.
Critics chastised the officials for speaking about annual vaccinations in light of the dearth of data on the updated boosters.
"Health authorities say a majority of Americans can count on annual COVID vaccinations moving forward, prior to having a scintilla of clinical data on the new boosters & [with] no idea about clinical meaningfulness & duration of effect. How are we supposed to think they're data-driven?" Jessica Adams, a former regulatory review officer at the Food and Drug Administration, wrote on Twitter.
"What they've shown in lab studies is that these bivalent vaccines help you to mount a slightly higher antibody response against Omicron. But whether that's going to translate into any kind of clinical efficacy, we don't know, because we don't really have those studies," Soumya Swaminathan, a World Health Organization official, said in a video this week.
The boosters contain elements of a strain that is in common with the BA.4 and BA.5 Omicron subvariants. BA.5 currently causes most of the COVID-19 cases in the country, according to federal genomic sequencing data.
PromotionFauci and other U.S. officials during the briefing encouraged people to get vaccinated.
"We fully expect that the updated bivalent vaccines containing BA.4 and BA.5 sequences will offer better protection against currently circulating strains than the original vaccines, although it is difficult to predict at this point, how much better that protection will be," Fauci said, citing data from human trials for a different formulation, a combination Wuhan-BA.1 shot.
Those trials showed the Pfizer and Moderna vaccines with BA.1 provided higher antibody levels than the original vaccines. Antibodies are believed to be a form of protection against the COVID-19 virus.
While other countries have approved that vaccine, the United States opted to ask manufacturers to switch BA.1 out in favor of the BA.4 and BA.5 sequences.
"One of the very reasons for this bivalent vaccine is not just because it keeps the great protection of the original strain and because it improves the protection against the BA.5 variant, as laboratory data suggests, but also that the laboratory data suggests it will improve protection against other variants as well," Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention, said. "So it gives us that breadth of protection that we might anticipate should another variant come through."