Novavax will only be able to offer a COVID-19 vaccine in the United States this autumn if regulators accept the shot it has started manufacturing that targets a variant that was dominant earlier this year, the company said.

Novavax’s updated vaccine targets a variant called JN.1, which is in line with European recommendations. The European Union’s regulator told vaccine makers last month to update their vaccines for that variant because they would likely be effective against its descendant lineages.

The U.S. Food and Drug Administration has not yet made a decision on the makeup of the next round of COVID vaccines and a JN.1 subvariant known as KP.2 has become dominant in the United States over the past month.

Novavax’s traditional, protein-based vaccine is developed in moth cells and takes months to manufacture. In 2023, for instance, Novavax said it needed six months to bring an adequate supply of vaccine to the market.

Vaccines based on messenger RNA (mRNA), like those from Moderna or Pfizer and partner BioNTech, can be developed more quickly. In the past, Pfizer has said it could make the shots in 100 days.

Moderna and Pfizer each told Reuters they are waiting for the FDA’s advisers to discuss vaccine design at a June 5 meeting before settling on which variant their next vaccines will target.

Novavax disclosed on its earnings call earlier this month that it had already advanced a version of its vaccine targeting JN.1 into commercial development.

“If a strain other than JN.1 is selected this late in the development process, a protein-based option will not be available for the U.S. population,” Novavax said in a statement emailed to Reuters this week. Novavax makes the only protein-based COVID vaccine for the U.S.

The Maryland-based company said in the statement it has data showing good cross-reactivity between its vaccine and the currently dominant KP.2 variant.

Novavax recently struck a licensing deal worth at least $1.2 billion with Sanofi for its COVID vaccine, bolstering a company that had lost most of its value since the pandemic.

It was only able to take a low-single-digit percentage market share in the U.S. during the 2023-2024 vaccination campaign as demand for COVID vaccines was smaller than hoped and the company got its shot to market later than rivals.

In 2024, the company expects revenue in the range of $400 million to $600 million, down significantly from last year, when it recorded $983.7 million in revenue.

Since 2022, regulators have asked vaccine makers to design new versions of the COVID shots to better target currently circulating variants.

Last year, both the U.S. and Europe settled on the same targets for their vaccine designs. In 2022, the European Medicines Agency (EMA) initially endorsed vaccines targeting a different variant than the ones authorized in the U.S.

The FDA recently postponed its vaccine advisory meeting from May 16 in order to have more time to “obtain surveillance data and other information” on the circulating virus.

The FDA did not immediately comment on its plans.

“Our hope is that the (FDA vaccine advisory committee) discussion and recommendation consider the public health benefit of chasing newer variants as well as the role of diverse vaccine options in supporting vaccine uptake,” Novavax said.

Reporting by Michael Erman; editing by Caroline Humer and Bill Berkrot