Jun 29, 2022 - Health

COVID vaccine strategy still murky after FDA experts meet

Prevalence of select COVID-19 Omicron variants
Data: CDC; Chart: Erin Davis/Axios Visuals

The COVID-19 vaccine strategy for the fall remains beset with unanswered questions after an FDA expert panel on Tuesday spent hours debating how and whether to update the shots.

Why it matters: Time is running short to develop a game plan with existing vaccines losing effectiveness against new variants and more than half of Americans still without a booster dose.

Driving the news: The Vaccines and Related Biological Products Advisory Committee voted 19-2 to recommend an Omicron-specific update to COVID-19 booster vaccines expected to be rolled out within the next few months.

But key questions were left unanswered:

  • The panel didn’t formally decide whether to update shots with the prevalent Omicron strain in circulation, currently the fast-spreading BA.4 and BA.5 subvariants, or the BA.1 lineage that emerged late last year, as the World Health Organization recommended.
  • The consensus appeared to be for a bivalent, or combination, booster combining the original COVID-19 strain that emerged in late 2019 with BA.4 and BA.5.
  • The FDA will continue to evaluate what to do about the primary series of vaccines for the fall.
  • Experts were split on whether there was enough data to recommend the updated shots for kids, or whether more studies are needed on dosage and possible side effects.
  • There also were concerns about what effect an updated vaccine would have on developing nations’ willingness to use older COVID shots to inoculate their populations.
  • And above all, it's unclear whether all the questions about who gets which shot when will add to public confusion and apathy that’s dogged the vaccination effort in recent months.

What they're saying: "None of us has a crystal ball and we’re trying to use every last ounce of what we can from predictive modeling and data that’s emerging to try to get ahead of a virus that's very crafty," said top FDA vaccine regulator Peter Marks.

  • "Unfortunately, looking in the past doesn’t help us a great deal to look in the future for [a] virus that has baffled a lot of us and made predictions almost irrelevant," said acting panel chairman Arnold Monto, a University of Michigan epidemiologist.

The timetable: Pfizer-BioNTech said an updated mRNA vaccine could be ready in October if regulatory uncertainties are ironed out. Moderna said it could have large amounts ready in late October or early November. Novavax is still awaiting emergency use authorization for its protein-based shot, but said it could have an updated vaccine by the fourth quarter.

The latest CDC data released Tuesday shows the Omicron subvariants BA.4 and BA.5 now make up more than 50% of the virus circulating in the U.S.

  • The profusion of new variants, combined with uncertainty over the immune responses, make devising a strategy at times resemble playing whack-a-mole.
  • "The virus is changing, and what worked two years ago may not work for future variants," University of Maryland virologist Meagan Deming told Nature. But updating vaccines won't be as simple as swapping genetic material based on the original COVID strain that emerged late in 2019 for one matching Omicron.

The bottom line: Despite a lack of clarity of where exactly the virus will take us next, the FDA committee ultimately erred on the side taking action, warning the virus might otherwise outrun efforts to protect against it.

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