An FDA advisory committee recommended the development of a new Covid-19
vaccine at its meeting on Wednesday. According to the panel, vaccine manufacturers should design updated vaccines to target the JN.1 variant of SARS-CoV-2. Ideally, these updated vaccines will be available in the fall.
The Vaccines and Related Biological Products Advisory Committee of the FDA evaluated the effectiveness of the current vaccines and discussed the need for a new vaccine formulation. Representatives from Moderna, Pfizer-BioNtech, and Novavax presented data about the protection offered by current vaccines against emerging variants and the potential benefits of vaccines specifically targeting these new strains.
Following the presentations and a period of public comment, the panel voted unanimously to recommend that the 2024-2025 Covid-19 vaccine should be a monovalent vaccine based on the JN.1 variant of SARS-CoV-2.
History of Covid-19 vaccines
To more fully understand today’s recommendation, it’s useful to review the history of today’s Covid-19 vaccines. In December 2020, the FDA provided emergency use authorization for mRNA-based vaccines produced by Moderna and Pfizer-BioNTech. Both companies designed their vaccines to target the ancestral, or original, strain of SARS-CoV-2. The FDA granted EUA to the Novavax vaccine in July 2022. Unlike the Moderna and Pfizer-BioNTech vaccines, this vaccine used a protein-based platform.
In the fall of 2022, both Moderna and Pfizer-BioNTech began offering bivalent vaccines that targeted both the ancestral virus and the BA.4/BA.5 forms of the Omicron variant. A year later, the FDA authorized all three manufacturers to provide vaccines developed to combat the XBB.1.5 subvariant of Omicron. With the committee’s latest recommendation, all three manufacturers now will begin developing JN.1-specific vaccines.
Benefits of a new vaccine
An updated vaccine potentially solves two problems. First, we know that Covid-19 immunity wanes over time. Second, we know that the virus continues to evolve, with new variants typically exhibiting some degree of immune escape. A representative from Moderna showed the committee compelling data addressing both points. Their XBB.1.5-specific vaccine offers strong protection against the XBB.1.5 virus, but that protection decreases over time. This vaccine offers some protection against currently circulating variants like JN.1 and KP.2, but the levels are reduced. And, that protection similarly declines over time. A new vaccine, then, presumably would elevate immunity against all variants and help our immune systems more effectively target the newer viruses.
Why JN.1?
Researchers first identified the JN.1 variant in the U.S. in August 2023 and its prevalence quickly increased. Today, however, other variants predominate. The CDC estimates that KP.2 and KP.3 make up over 40% of the infections in the U.S. Only about 8% of current infections are caused by JN.1. So why develop a JN.1-specific vaccine? Dr. Archana Chaterjee, Dean of the Chicago Medical School, remarked during the meeting, “The potential for immunogenicity from a JN.1 vaccine to cover those variants seems to be pretty good.” Dr. Alan Berger from the NIH concurred, stating that the existing data, “really does suggest that JN.1 is the appropriate vaccine update to be making at this time.”
But a JN.1-based vaccine certainly isn’t a panacea. Dr. Chaterjee went on to comment that, “Whatever we choose today or recommend today is probably not what is going to be circulating in a few weeks or a few months from now.” The virus will continue to change. Unless researchers develop a so-called variant-proof vaccine, we will continue to play catch-up. Today’s recommendation by the FDA panel certainly won’t be their last recommendation.
