Just recently, the Food and Drug Administration (FDA) announced Thursday that it has advised vaccine manufacturers to update their COVID-19 vaccines to target the KP.2 strain, a descendant of the highly contagious JN.1 variant.
This decision comes as part of preparations for the fall vaccination campaign, aiming to enhance protection against the current dominant strains.
FDA's Decision on the COVID Vaccine Update
Just over a week ago, an FDA premonitory panel unanimously recommended that the COVID-19 vaccines for the forthcoming fall season be streamlined to target the JN.1 variant or one of its descendants.
Despite the amicable vote, there was a notable disagreement between panel members and Dr. Peter Marks, the FDA's top vaccine controller, regarding which specific strain to target.
While most panel members expressed a preference for the JN.1 strain, Dr. Marks supported opting for a more current strain, similar to KP.2.
Marks explained that they're paying an incredibly high price for mRNA vaccines to be suitable for having the freshest vaccines, likening the situation to copping fresh milk from the store.
On June 6, the FDA advised drugmakers to target the JN.1 variant. However, continued monitoring of circulating strains and the recent rise in COVID-19 cases led the FDA to further estimate their recommendation.
The agency ultimately determined that the preferred JN.1-lineage for the updated vaccines is the KP.2 strain, if feasible, based on the most current data available.
Current COVID-19 Strain Trends in the U.S.
According to the Centers for Disease Control and Prevention (CDC), the JN.1 variant has largely fallen out of circulation in the U.S.
As of the most recent data, the KP.2 strain accounts for 22.5% of new COVID-19 cases, with its sister variant, KP.3, making up 25% of new cases. This shift in dominant strains underpins the FDA's recommendation to update the vaccines to target KP.2.
This updated guidance will enable vaccine manufacturers to start producing and distributing the revised shots, which are anticipated to play a crucial role in the fall COVID-19 vaccination campaign.
Three companies are currently producing COVID-19 vaccines: Pfizer, Moderna, and Novavax. While Pfizer's and Moderna's vaccines are based on mRNA technology, Novavax produces protein-based vaccines.
Due to the longer manufacturing time required for protein-based vaccines, Novavax has indicated it will not be able to produce a KP.2 vaccine in time for the fall. Instead, it plans to distribute a JN.1 vaccine that it has already been working on.
Routine Updates for COVID Vaccines
This marks the third update to COVID-19 vaccines to align with circulating strains. The process of selecting the next round of vaccines is becoming routine, resembling the annual flu vaccine update. Vaccine experts convene in the spring to select the strain for the fall vaccination campaign.
During the advisory committee meeting, the vaccine manufacturers presented data indicating that a JN.1 vaccine would likely generate higher levels of antibodies against the circulating strains compared to the current vaccine, which targets the now-outdated XBB.1.5 subvariant.
The advisory committee did not make a recommendation on which groups should receive the updated vaccine, leaving that decision to the CDC.
The CDC is scheduled to hold its advisory committee meeting later this month to provide further guidance on vaccine administration.
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