The FDA is now advising manufacturers to develop the 2024-2025 COVID-19 vaccines using the KP.2 strain for the formula, the agency announced June 13.
The update comes just one week after an FDA committee voted unanimously June 5 on the 2024-2025 COVID-19 vaccine makeup, recommending it should be one that targets the monovalent JN.1-lineage.
Following the June 5 vote, the committee further discussed if a specific strain from that lineage should be considered for the new vaccines to target, which is what led to this slight change in direction for manufacturers.
KP.2 is part of the JN.1 lineage, but the specification to use the KP.2 strain resulted from current data, which shows that the current COVID-19 strains in circulation are more closely related to it.
Right now, per CDC data, a variant known as KP.3 accounts for 25% of circulating cases, followed by KP.2, which constitutes another 22.5% of cases. Behind the two are LB.1, also a JN.1 sub-variant, making up 14.9% of cases, as well as KP.1.1 at 7.5%.
"This change is intended to ensure that the COVID-19 vaccines (2024-2025 Formula) more closely match circulating SARS-CoV-2 strains," the FDA wrote in its update. "FDA has communicated this change to the manufacturers of the licensed and authorized COVID-19 vaccines. The agency does not anticipate that a change to KP.2 will delay the availability of the vaccines for the United States."