The US Food and Drug Administration is poised to sign off as soon as this week on updated Covid-19 vaccines targeting more recently circulating strains of the virus, according to two sources familiar with the matter, as the country experiences its largest summer wave in two years.
The agency is expected to greenlight updated mRNA vaccines from Moderna and Pfizer/BioNTech that target a strain of the virus called KP.2, said the sources, who declined to be named because the timing information isn’t public. It was unclear whether the agency simultaneously would authorize Novavax’s updated shot, which targets the JN.1 strain.
The move would be several weeks ahead of last year’s version of the vaccine, which got FDA signoff on September 11.
“Now is the time to get a dose with this surge,” Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told CNN.
Osterholm said on his podcast last week that he recently got a dose of last season’s vaccine in order to increase his immunity while the virus is circulating at such high levels and amid uncertainty around when new shots would become available.
He added that he’ll now wait to get the updated one in four months, the interval recommended by health officials.
In June, the US Centers for Disease Control and Prevention recommended that everyone over 6 months old receive both an updated Covid-19 vaccine and a flu shot this year.
Representatives for Pfizer and Moderna told CNN that the companies had ample supply of their updated Covid vaccines and would be ready to ship doses upon approval. Moderna’s spokesman said it expects the vaccine to be available in stores within days of FDA signoff.
Novavax’s vaccine is based on protein technology, which takes longer to manufacture than mRNA vaccines. The company’s executives told investors on a conference call last week that it anticipated that its updated vaccine would be arriving in warehouses this month and that it’s expected to be ready for distribution when authorized. A spokesperson for Novavax didn’t immediately respond to a request for comment Friday.
A spokesperson for the FDA said the agency can’t comment on timing of product applications but noted that it “anticipates taking timely action to authorize or approve updated COVID-19 vaccines in order to make vaccines available this fall.”
Levels of the SARS-CoV-2 virus, which causes Covid-19, measured in wastewater are at “very high” levels nationally, according to CDC data, sparking the highest summer peak in the US since July 2022. Monitoring of viral levels in wastewater can give a picture of how widespread the virus is as testing and other forms of monitoring the virus have fallen off.
Measures of severe disease, including rates of hospitalization and death, have been rising, according to the CDC, but they’re nowhere near levels seen in previous years.
Waves of the virus are driven by both waning immunity and new variants, experts say. The prevalent strain in the US now is KP.3.1.1, according to CDC data, estimated to account for 37% of cases over the past two weeks. That’s triple its level a month ago.
KP.3.1.1 and KP.2 – the strain included in the updated mRNA vaccines – are both offshoots of JN.1, the target of Novavax’s shot, and all are versions of the Omicron variant.