As the Biden administration lays the groundwork to fast-track an omicron-specific Covid-19 vaccine, former FDA Commissioner Scott Gottlieb recommends sticking with the "ancestral strain" for as long as possible to provide better protection against "the full complement of different variants."
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FDA lays groundwork to fast-track omicron vaccine
Federal regulators on Sunday said FDA is in conversations with drugmakers about streamlining the approval process for a Covid-19 vaccine booster specifically targeting the omicron variant.
President Joe Biden on Monday said FDA and CDC will use "the fastest process available without cutting any corners for safety" to authorize the new vaccines.
Specifically, FDA will allow drugmakers to meet standards like those established for booster shots, one person familiar with the matter told the Wall Street Journal. For example, drugmakers won't be required to conduct large, long clinical trials for their vaccines, but will instead be allowed to study the immune response of a few hundred people, the Journal reports.
One person familiar with the matter told the Journal that drugmakers will need about three months to develop and test their new vaccines. Then they could seek authorization through an expedited review process and FDA would take about one to two weeks to make a decision.
The case in favor of omicron-specific vaccines
Immunologists have warned that the omicron variant contains dozens of mutations that may help it to partially escape existing coronavirus immunity.
For instance, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has said, "[T]he profile of the mutations strongly suggest that ... it might evade immune protection that you would get, for example, from a monoclonal antibody or from the convalescent serum after a person's been infected and possibly even against some of the vaccine-induced antibodies."
Further, early data from South Africa suggests the omicron variant is at least three times as likely to cause coronavirus reinfection as other variants.
Faced with these troubling signs of potential immune escape, manufacturers of Covid-19 vaccines—including Pfizer/BioNTech and Moderna—are scrambling to test their current vaccines against omicron and to update them if necessary.
Why omicron-specific vaccines could backfire
However, other public health experts warned that a vaccine carefully tailored to omicron could prove counterproductive in a fast-changing pandemic where new variants are constantly emerging.
On Sunday, Gottlieb said "there’s reason to believe" that vaccines specifically targeting one variant might not work against others.
"This is going to be a really critical decision because what we've seen in the past, for example, when we engineered a vaccine to specifically target 1351, the old South African variant, was that vaccine worked well or appeared to work well against 1351 but didn't appear to provide as good coverage against all the other variants," said Gottlieb, who is also on the board at Pfizer.
"And there's reason to believe that as you develop vaccines that are very specific to some of these new variants, they may not work as well against the full complement of different variants that we've seen," he added. "So you wanted to try to stick with the ancestral strain, the Wuhan strain, in the vaccine, I think, as long as possible."
Gottlieb added that, as the virus starts to mutate, it "probably starts to hide some of the viral targets on its surface," meaning the vaccine developed doesn't give as "broad immunity to the full complement of targets on its surface."
Omicron will likely not be the last coronavirus variant
Meanwhile, NIH Director Francis Collins on Sunday said "it's certainly possible" that omicron won't be the last coronavirus variant that emerges.
"It's certainly possible that this is not the last emerging variant that will attract a lot of attention and a lot of concern," Collins said. "This one does have the largest number of mutations that we've seen so far. Omicron with about 50 mutations compared to the original."
Collins added that omicron may have developed in the body of an immunocompromised person who was unable to completely fight off the virus.
"So it remained in the system maybe for months in that person until they finally got over it," he said. "And that is of course a perfect situation for the virus to be able to pick up additional mutations along the way. To the extent that that's gonna keep happening, if we don't have adequate immune protection across the globe—yeah, we're probably gonna see something. We'll have to use some of the other letters in the Greek alphabet." (Douglas/Armour, Wall Street Journal, 12/5; Schwartz, Wall Street Journal, 12/3; Vakil, The Hill, 12/5 ; Vakil, The Hill, 12/5 ; Vakil, The Hill, 12/5 )