Decision looms on whether to offer modified vaccine

FDA to discuss updated shots targeting omicron made by Pfizer, Moderna

U.S. health authorities are facing a critical decision: whether to offer new COVID-19 booster shots this fall that are modified to better match recent changes of the shape-shifting coronavirus.

Moderna and Pfizer have tested updated shots against the super-contagious omicron variant, and advisers to the Food and Drug Administration will debate today if it’s time to make a switch — setting the stage for similar moves by other countries.

“This is science at its toughest,” FDA vaccine chief Dr. Peter Marks told The Associated Press, adding that a final decision is expected within days of the advisory panel’s recommendation.

Current COVID-19 vaccines saved millions of lives around the world in just their first year of use. And the Moderna and Pfizer shots still offer strong protection against the worst outcomes — severe illness and death — especially after a booster dose.

But those vaccines target the original coronavirus strain and between waning immunity and a relentless barrage of variants, protection against infections has dropped markedly. The challenge is deciding if tweaked boosters offer a good chance of blunting another surge when there’s no way to predict which mutant will be the main threat.

In an analysis prepared for today’s meeting, FDA officials acknowledged targeting last winter’s version of omicron is “somewhat outdated” since it already has been replaced by its even more contagious relatives.

“We would obviously like to get it right enough,” Marks said, so that with one more shot “we get a full season of protection.”

Many experts say updated boosters promise at least a little more benefit.

“It is more likely to be helpful” than simply giving additional doses of today’s vaccine, said epidemiologist William Hanage of the Harvard T.H. Chan School of Public Health.

That’s assuming the virus doesn’t throw another curve ball.

“We’re following rather than getting ahead which is so vexing — that we haven’t come up with a better variant-proof vaccine,” said Dr. Eric Topol, head of the Scripps Research Translational Institute, who has urged a major government push for next-generation immunizations.

Adding to concern about a winter COVID-19 wave is that about half of Americans eligible for that all-important first booster dose never got it. An updated version might entice some of them.

But “we do need to change our expectations,” said Dr. William Moss of the Johns Hopkins Bloomberg School of Public Health, who noted that studies early in the pandemic raised unrealistic hopes of blocking even the mildest infections. “Our strategy can’t be booster doses every couple of months, even every six months, to prevent infections.”

The top candidates are what scientists call “bivalent” shots — a combination of the original vaccine plus omicron protection.