An all-star panel of COVID-19 experts will convene this week to hash out how and when vaccines should be updated to address future variants as the virus continues to rapidly mutate.
The meeting of U.S. Food and Drug Administration advisers should provide some of the first hints of its strategy to map out a more proactive plan for developing strain-specific boosters. Until now, the process has been led by drugmakers such as Moderna Inc. and Pfizer Inc., which have gained approval for boosters for specific populations.
This is likely just the beginning. Many researchers believe the vaccines will need to be periodically updated to counteract new strains, just like annual flu shots. Figuring out how best to do this may be crucial to staving off future COVID-19 waves.
Unlike the well-established routines for revising flu vaccines, there is no playbook for how to update Covid shots. The virus hasn’t settled into a clear seasonal pattern, and researchers simply don’t know whether it will continue to mutate quickly.
At the FDA meeting, expert advisers will review who could be eligible for additional boosters, the timing between doses and whether the agency’s role in updating vaccines would mimic the current process for flu shots.
No vote is planned at Wednesday’s advisory meeting and there will be no discussion of specific applications from drug companies.
Nonetheless, the stakes are high for both Moderna and Pfizer, as the meeting could help begin to set broad contours for when vaccines should be updated. If COVID-19 shots end up being revised annually, that could lead to billions of dollars of additional sales for both companies.
There is still much to learn about how emerging variants impact vaccine effectiveness, FDA staff said in a briefing document published Monday. “Accumulating data suggest that the composition of vaccines may need to be updated at some point to ensure the high level of efficacy demonstrated in the early vaccine clinical trials,” they added.
The early portion of the panel will focus on the latest data on what the virus may hold in store and how best to prepare future iterations of the vaccine.
Researchers from Israel will present data from the country’s fourth-shot campaign using Pfizer’s booster. Centers for Disease Control and Prevention scientists will explain the latest epidemiology on variants, and Trevor Bedford, a virus evolution expert at the Fred Hutchinson Cancer Research Center, will talk about the potential for future strains. Kanta Subbarao, a Melbourne-based virologist who chairs the World Health Organization panel devising criteria for vaccine updates, will provide that agency’s perspective on variant-specific shots.
After a public comment period, much of the afternoon session will feature a discussion among panel members about what to do next. The group, called the Vaccines and Related Biological Products Advisory Committee, advises the FDA on immunizations. The agency isn’t obligated to follow the recommendations of the panel, though it typically does.
Omicron’s BA.2 strain has become dominant in the U.S., leading to concerns about a resurgence of cases and the need for additional safeguards. In the U.K., researchers have recently found a potentially more transmissible hybrid strain called XE. In the U.S., booster doses are becoming an increasingly relied-upon tool in the fight against COVID-19, especially as states and companies cut back on precautions such as masking and working from home.
Both Pfizer and Moderna are working on omicron-specific boosters and on shots that combine existing vaccines with the variant-specific formulation.