PROVIDENCE, R.I. (WPRI) — A vote by an expert panel did not approve new recipes for COVID-19 vaccine boosters, but it did pave the way for the U.S. Food & Drug Administration (FDA) to push manufacturers to create them ahead of an expected winter surge.

The Vaccines and Related Biological Products Advisory Committee voted 19-2 that COVID-19 boosters should contain some version of the omicron variant.

Dr. Peter Marks, director of FDA’s Center for Biologics Evaluation and Research, noted how it will be difficult to know which version of the virus will be impacting the country in the fall or winter months.

The two newest omicron subvariants, referred to as BA.4 and BA.5, together now make up half of the country’s cases, according to the U.S. Centers for Disease Control and Prevention.

“BA.4 or 5 may not be circulating later this fall, but by moving to this, whether it’s a bivalent or in some part of the vaccine composition, we may bring the immune system closer to being able to respond to what’s circulating,” Marks explained during the advisory committee meeting on Tuesday.

Dr. Eleftherios Mylonakis, chief of infectious diseases at The Miriam and Rhode Island hospitals, said the process to update COVID-19 shots is not like it is for influenza shots, at least not yet.

“A few months before the flu season, we have an understanding of what is circulating in the southern hemisphere, and then we can make a reasonable hypothesis and guesses of what we’re going to focus on vaccines,” Mylonakis told 12 News.

However, Mylonakis said the virus that causes COVID-19 hasn’t yet reached a predictable, year-round scenario.

“It still changes drastically,” he said.

Mylonakis said while all the current vaccines still provide a level of protection, those who were vaccinated are facing waning immunity and only about half of Americans are up to date on COVID-19 vaccines.

For those reasons and more, he’s expecting an increase in cases in the months ahead.

“We need to adjust, and hopefully with the new omicron-focused vaccines, we’re going to have a good response that will stay for a longer period of time and will be able to help us over the next few months,” he added.

It’s not clear if all Americans would be offered a modified booster. The shots may only be recommended for older adults and others at higher risk.