The FDA’s directive means the COVID-19 vaccine will undergo just its second update since it was developed.

But deciding on the strain was the easy part — public health officials will now be tasked with a new messaging campaign to encourage vaccinations among a checked-out public, after poor uptake of the most recent booster.

Just 17 percent of Americans have received a bivalent booster dose since they were rolled out last year.

Data presented to an FDA advisory panel on Thursday showed that protection against hospitalization drops considerably four to six months after a bivalent booster.

During the meeting, some vaccine experts said the Biden administration needs to decide if it will continue with its previous message that everyone should get an updated shot, or if officials should concentrate efforts toward those who are most at risk of falling severely ill to the virus, such as the immunocompromised and older adults. 

Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, indicated the agency will likely try to market the shot as a yearly update, like the annual flu shot.

“We all certainly agree that COVID-19 is not influenza, but from a public health standpoint in which you need to make tens upon tens of millions of vaccine doses, get them deployed and get them into people’s arms … it reduces to a similar type of campaign,” Marks said during the meeting last week. 

Targeting the XBB.1.5 strain comes with a bit of a risk, as the virus mutates so often to evade immunity that it may not be the most dominant strain in the autumn and winter.

But the different strains of XBB are similar enough to each other that even if the shot isn’t an exact match, it will be close enough to provide cross-protection from severe disease.

“People need to be able to understand what we’re doing,” Marks said. “People understand a yearly influenza vaccine… I think this our best effort to try to help make things clear. We have not done a good job to date communicating to the American public what’s going on here because they are still not getting these vaccines in the way we’d like to see.”