The U.S. Food and Drug Administration has advised vaccine makers to update the COVID booster shot to target the new form of the Omicron variant.exist call for change, the FDA listened to the recommendations of its Vaccines and Related Biologics Advisory Committee (VRBPAC), which voted 19-2 to support the booster for Omicron after a public meeting on June 28. The new booster could roll out this fall, but it may be too late to stop the current surge in cases in the US and other countries caused by Omicron subvariants BA.4 and BA.5.
Existing vaccines target the ancestral form of SARS-CoV-2, which first emerged in Wuhan, China. But while these injectables still broadly prevent serious disease, “their effectiveness appears to have diminished over time,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said at the VRBPAC meeting in late June. Each new variant is more contagious than its predecessor. Around the world, omicron sub-variants have been fueling increases in infections and hospitalizations—the latter especially in older adults.
The planned update is currently limited to an mRNA vaccine booster developed by Moderna and Pfizer-BioNTech. The companies are now racing against time to test new products and produce millions of doses to supply the FDA’s planned fall booster campaign.
scientific american The prospects for these lenses were discussed with experts from academia and industry.
How will the new booster be different?
So far, COVID vaccines have only targeted ancestral viruses. In addition to the virus, the new booster will target the BA.4 and BA.5 Omicron sub-variants, which account for about 70% of new COVID cases in the U.S. as of July 2, according to the FDA’s recommendation. In choosing these targets, VRBPAC members felt it would be wise to match boosters to currently circulating strains without sacrificing the protection against severe disease conferred by injections against the ancestral virus. “We strongly believe that current vaccines are still very effective, and we don’t want to lose that,” said Archana Chatterjee, dean of the Chicago School of Medicine and VRBPAC member. But Chatterjee added that with new variants appearing every three to four months, there is no guarantee of BA. .4 and BA.5 will still dominate when the fall booster event begins.
Can an Omicron-adapted vaccine be given to people who have not yet been vaccinated?
As things stand, the answer is no. These lenses are only used as boosters. Unvaccinated people will still have access to major vaccine lines based on ancestral strains.
How effective is the Booster for Omicron?
So far, public evidence has been limited to what Pfizer-BioNTech and Moderna disclosed in press releases — specifically the update booster for the first Omicron variant, known as BA.1. Based on preliminary evidence, the vaccines produced levels of neutralizing antibodies (antibodies that help the body fight the virus) twice as high as those produced by the company’s existing vaccines. However, the data are only part of the story, as “there is no clear line as to what levels of antibodies correlate with disease protection,” said Ofer Levy, VRBPAC member and director of the Precision Vaccines Program at Boston Children’s Hospital. Furthermore, the extent to which Omicron-adapted boosters might trigger additional protection against immune cells called T cells and B cells remains unknown. Both companies have begun testing bivalent boosters for BA.4 and BA.5, but have not released any data publicly.
How long will the effects of the new boosters last?
It’s hard to say. This protection can last as long as newly evolved variants of Omicron emerge. But if the next major variant pops up — like the Delta and the original Omicron — then lasting protection is even more questionable. However, based on current evidence, not all experts agree that adapting Omicron’s booster is reasonable. Paul Offit, a pediatrician at Children’s Hospital of Philadelphia, agrees that boosters targeting at-risk groups are needed this fall. But he believes that as long as existing vaccines prevent serious illness and hospitalization, they can achieve this intended purpose. Offit was one of two VRBPAC members who voted against the updated footage. “We can all agree that the ancestral ingredients need to be there,” he said. “But does adding the Omicron component significantly boost the antibody against the next daughter variant? There’s no evidence it will.”
Will the new boosters be available to all age groups, including young children?
This is still unclear.in email reply scientific americanan FDA spokesperson wrote, “The FDA expects that, based on the data that manufacturers will submit, it will be able to authorize improved boosters for those populations deemed suitable to receive them.” However, the agency declined to further detail its review process. .
What will happen now?
Both Pfizer-BioNTech and Moderna claim they can start dosing the bivalent BA.4-BA.5 booster in October. However, the companies also said they needed more guidance from the FDA on the kinds of data they would need to submit for regulatory authorization. The wild card is clinical information on how many human participants the FDA will look for. Existing vaccines are licensed on the basis of large-scale clinical trials involving tens of thousands of people. Boosters for Omicron are built using the same manufacturing platform and materials. The company hopes these products will only be authorized based on preclinical data showing sufficient levels of neutralizing antibodies. “As long as the FDA accepts preclinical data rather than the standard clinical data from the previous emergency use authorization, we will be able to meet the October deadline,” said Moderna spokeswoman Elise Meyer. Anything else “will be a change in regulatory approach.”