O Food and Drug Administration said Thursday advised drugmakers to update Covid vaccines to target the KP.2 strain, a descendant of the highly contagious JN.1 variant that began circulating widely in the US this winter.
The announcement came just over a week after an FDA advisory panel voted unanimously to recommend that the Covid vaccines for fall will be updated to target JN.1 variant or one of his descendants.
After the vote, there was a disagreement between panel members and Dr. Peter Marks, the agency’s chief vaccine regulator, over which strain the agency should choose. The majority of panel members expressed a preference for JN.1while Marks preferred to select a more recent strain, as KP.2.
“We are paying an incredibly high premium for the mRNA vaccines so we can have the freshest vaccines,” Marks said, comparing the shots to buying milk at the store.
After the committee meeting, the FDA said that on June 6 it initially advised drugmakers to target the JN.1 variant. However, the agency continued to monitor circulating strains and, “based on the most current data available, along with the recent increase in Covid-19 cases in areas of the country, the agency further determined that the preferred JN.1- lineage” for the updated vaccines is the KP.2 strain, “if possible,” the FDA said.
JN.1 has largely gone out of circulation in the US, according to the Centers for Disease Control and Prevention. As of Saturday, KP.2 represented 22.5% of new Covid cases in the US. KP.3, a sister variant, accounted for 25% of new cases.
The FDA’s decision will allow drugmakers to begin producing and distributing the shots, which are expected to be used as part of a Covid vaccination campaign in the fall.
Three pharmaceutical companies are producing vaccines against Covid: Pfizer, Moderna and Novavax. Pfizer and Moderna’s vaccines are based on mRNA, while Novavax’s is based on proteins. Because protein-based vaccines take much longer to manufacture, Novavax has indicated that it will not be able to manufacture a KP.2 vaccine in time for the fall. Instead, it is expected to distribute a JN.1 vaccine, which it had already been producing.
This is the third time that vaccines have been updated to target circulating strains. The process of selecting the next round of vaccines is falling into a routine, similar to the way the annual flu shot is updated, with vaccine experts selecting the strain in the spring for a fall vaccination campaign.
During the advisory committee meeting, drugmakers presented data showing that a JN.1 vaccine should generate higher levels of antibodies against circulating strains of the virus compared to the current vaccine, which targets XBB.1.5, a subvariant which is no longer in circulation.
The committee did not make a recommendation on who should receive the updated vaccine. That will be up to the CDC, which will hold its own advisory committee meeting later this month.
This article was originally published in NBCNews. with
