The US Food and Drug Administration on Friday recommended that Covid vaccine manufacturers produce one strain shots for the case that the target of the omicron subvariant XBB.1.5, dominant strain virus nationwide.

“Based on all the evidence, the FDA has recommended to manufacturers updating their COVID-19 vaccines that they should develop vaccines with a monovalent formulation of XBB 1.5,” the agency said in a statement. releasereferring to pharmaceutical companies Pfizer, modern and Novavax.

Monovalent means that the bullet is designed to protect against one variant Covid.

XBB.1.5 is a descendant omicron variantwhich caused cases in the US jump to a record level early last year. It is also one of the most immune evasive strains to date.

XBB.1.5 accounted for nearly 40% of all US Covid cases in early June, according to data from the Centers for Disease Control and Prevention. This proportion is slowly decreasing, while cases of the related variants XBB.1.16 and XBB.2.3 are increasing.

The FDA’s decision is consistent with what the agency’s advisory panel is recommended on Thursday.

This panel voted unanimously that the new strikes should be monovalent and target a member of the XBB family. The advisors also generally agreed that the most ideal option would be to target XBB.1.5.

The FDA selection is also good news for Pfizer, Moderna and Novavax.

The three companies are already developing updated versions of their missiles that target the XBB.1.5. Preliminary data presented by each company on Thursday indicated that the hits elicit strong immune responses against all XBB variants.

“Novavax is encouraged by today’s FDA announcement and the company’s XBB 1.5 COVID vaccine candidate is being produced at commercial scale with the intention of being on the market for the fall vaccination campaign,” a Novavax spokesperson said in a statement to CNBC.

Pfizer said it will be able to deliver a monovalent missile targeting XBB.1.5 by July. Moderna and Novavax did not provide specific delivery dates.

Dr. Peter Marks, head of the FDA’s vaccine division, suggested on Thursday that the updated vaccines could be available to the public around September.