Vaccine makers are rushing to update their COVID-19 vaccines against the latest coronavirus threat even before it’s clear a change is needed, just in case.
Experts doubt today’s shooting will become unnecessary, but say it’s critical to see how quickly companies could produce a reformulated dose and prove it works – because no matter what happens with omicron, this new mutant will not be the last.
Omicron “sounds the fire alarm.” Whether this is a false alarm, it would be really good to know if we can actually do it – get a new vaccine rolled out and be ready, ”said immunologist E. John Wherry of the University of Pennsylvania. .
It is too early to know how the vaccines will resist omicron. The first clues this week were mixed: Preliminary lab tests suggest that two doses of Pfizer may not prevent infection with omicron, but it may protect against serious illness. And a booster can boost immunity enough to do both.
Better responses are expected in the coming weeks, and regulators in the United States and other countries are watching closely. The World Health Organization has appointed an independent scientific panel to determine whether the injections need to be reformulated because of the omicron or any other mutant.
But authorities haven’t explained what would trigger such a drastic measure: if vaccine immunity against a serious disease wanes, or if a new mutant simply spreads faster?
“This is not trivial,” said BioNTech CEO Ugur Sahin, Pfizer’s vaccine partner, shortly before the discovery of omicron. A company might ask to market a new formula “but what if another company makes another proposal with another variation?” We don’t have an agreed strategy.
It’s a tough decision – and the virus is moving faster than science. Just this fall, U.S. government vaccine advisers wondered why the boosters hadn’t been retooled to target the extra-contagious delta variant – only so that the next creepy mutant, omicron, was neither a delta descendant nor a very close cousin.
If the vaccines need tweaking, there is yet another question: should there be a separate omicron booster or a combination injection? And if it’s a combo, should it target the original strain with omicron, or the currently dominant delta variant plus omicron? Here is what we know.
COMPANIES DO NOT START FROM ZERO
COVID-19 vaccines work by triggering the production of antibodies that recognize and attack the advanced protein that covers the coronavirus, and many are made with new technology flexible enough for easy updating. The Pfizer and Moderna vaccines are the fastest to modify, made with genetic instructions that tell the body to make harmless copies of the spike protein – and that messenger RNA can be swapped out to match new mutations.
Pfizer expects a specific omicron candidate to be ready for review by the Food and Drug Administration in March, with a few initial batches ready to ship around the same time, the scientific director said, Dr. Mikael Dolsten, at The Associated Press.
Moderna allows 60-90 days to have a specific omicron candidate ready for testing. Other manufacturers who make COVID-19 vaccines using different technology, including Johnson & Johnson, are also pursuing possible updates.
Pfizer and Moderna have already successfully prepared experimental doses to match delta and another variant named beta, shots that weren’t necessary but offered valuable practice.
NOT CLEAR IF ADJUSTMENTS ARE NECESSARY
So far, the original vaccines have offered at least some cross-protection against the earlier variants. Even though immunity to omicron is not as good, Dr Anthony Fauci, America’s leading infectious disease expert, hopes the large jump in antibodies triggered by the booster doses will compensate.
Pfizer’s preliminary lab tests, released on Wednesday, suggest it may be, but antibodies aren’t the only layer of defense. The vaccines also stimulate T cells which can prevent serious illness if someone is infected, and Pfizer’s early testing showed, as expected, that these do not appear to be affected by omicron.
In addition, memory cells that can create new and somewhat different antibodies are formed with each dose.
“You’re really training your immune system to not only handle the existing variants better, but it actually prepares a larger repertoire to deal with the new variants,” Dolsten said.
The aggressiveness of a mutant also plays a role in vaccine reformulation. Omicron appears to spread easily, but early reports from South African scientists suggest it could cause milder infections than previous variants.
HOW TO KNOW IF THE UPDATES ARE WORKING
The FDA said companies wouldn’t need massive studies of modified vaccines, but small studies to measure whether people receiving the updated vaccine have immune responses comparable to the original and highly effective vaccines.
Wherry does not expect data from volunteers testing experimental shots targeted by omicron until at least February.
WHAT ABOUT COMBINED PLANS?
Influenza vaccines protect against three or four different strains of influenza in a single injection. If a vaccine adjustment is needed for omicron, authorities will need to decide whether to make a separate omicron booster or add it to the original vaccine – or maybe even follow the flu model and try a different one. combination.
There is evidence that a combined COVID-19 shot could work. In a small Moderna study, a so-called bivalent booster containing the original vaccine and a beta-specific dose caused a larger antibody jump than an original Moderna booster or its experimental beta-specific injection.
And scientists are already working on next-generation vaccines that target parts of the virus least likely to mutate.
Omicron is bringing “another important wake-up call,” Wherry said – not only to immunize the world, but to create more versatile options for doing this job.
PA reporter Jamey Keaten contributed to this report.
The Associated Press’s Department of Health and Science receives support from the Department of Science Education at Howard Hughes Medical Institute. The AP is solely responsible for all content.