Updated Covid-19 Vaccine Targeting JN.1 Recommended by FDA Panel

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 that target the JN.1 variant of SARS-CoV-2. Ideally, these updated vaccines will be available in the fall.

The Advisory Committee on Vaccines and Related Biological Products of the FDA evaluated the effectiveness of current vaccines and discussed the need for a new vaccine formulation. Representatives from Moderna, Pfizer-BioNtech and Novavax presented data on 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 better understand today’s recommendation, it is helpful to review the history of current Covid-19 vaccines. In December 2020, the FDA granted 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 fall 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 cleared all three manufacturers to supply vaccines developed to combat Omicron’s XBB.1.5 subvariant. With the committee’s latest recommendation, all three manufacturers will now begin development of JN.1-specific vaccines.

Benefits of a new vaccine

An updated vaccine may solve two problems. First, we know that immunity to Covid-19 wanes over time. Second, we know that the virus continues to evolve, with new variants typically exhibiting some degree of immune escape. A Moderna representative showed the committee compelling data on both points. Their XBB.1.5-specific vaccine provides strong protection against the XBB.1.5 virus, but that protection wanes over time. This vaccine provides some protection against currently circulating variants such as JN.1 and KP.2, but the levels have been reduced. And that protection similarly diminishes over time. A new vaccine would therefore probably increase immunity against all variants and help our immune system to tackle the newer viruses more effectively.

Why JN.1?

Researchers first identified the JN.1 variant in the US in August 2023 and its prevalence increased rapidly. Nowadays, however, other variants predominate. The CDC estimates that KP.2 and KP.3 account for more than 40% of infections in the US. 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, noted at the meeting: “The potential for immunogenicity of a JN.1 vaccine to cover these variants appears to be quite good.” Dr. The NIH’s Alan Berger agreed, stating that the existing data “really suggest that JN.1 is the appropriate vaccine update to make at this time.”

But a JN.1-based vaccine is certainly not a panacea. Dr. Chaterjee went on to say, “Whatever we choose or recommend today is probably not what will be in circulation in a few weeks or a few months.” The virus will continue to change. Unless researchers develop a so-called variant-proof vaccine, we will continue to catch up. Today’s recommendation by the FDA panel will certainly not be their last.