Health secretary Robert F. Kennedy Jr. has expressed another unorthodox view on vaccines, with the long-time vaccine critic declaring that vaccines for respiratory bugs that target a sole part of the pathogen they are meant to protect against do not work.
The claim was dismissed as erroneous by vaccine experts, who were befuddled by the secretary’s theory, espoused during an interview with CBS News.
Kennedy made the claim in explaining a controversial recent decision by political appointees at the Food and Drug Administration to delay granting a full license to Novavax’s Covid-19 vaccine, which is still given under an emergency use authorization or EUA.
“It is a single antigen vaccine. And for respiratory illnesses, the single antigen vaccines have never worked,” Kennedy said when asked by CBS’s chief medical correspondent, Jonathan LaPook, why the decision was delayed.
Scientists who have developed and studied vaccines were blunt in their assessment of Kennedy’s claim.
“He’s wrong,” said Paul Offit, an infectious diseases expert at Children’s Hospital of Philadelphia who was one of the developers of a successful rotavirus vaccine. “He believes falsely that a single protein vaccine can’t effectively prevent a serious mucosal infection and of course it can. We have several examples.”
Peter Marks, the former head of the FDA’s biologics center, which regulates vaccines, said Kennedy’s idea about single antigen vaccines isn’t based in science.
“A tenet of virology is that you go after one of the proteins on the surface that generates a good immune response, and that’s what you target. This principle has withstood the test of time because we’ve made multiple good vaccines in that manner,” said Marks, who was pushed out of the FDA late last month at the behest of Kennedy.
“This is another example of Kennedy being an ignoramus about vaccination, if not other things as well. And you can quote me on that,” said Stanley Plotkin, a co-developer of the rotavirus vaccine and of the vaccine that protects against rubella. Plotkin is a professor emeritus at the University of Pennsylvania.
An antigen is a substance that activates the immune system to protect against a specific disease threat. Some vaccines, such as the one that protects against measles, target multiple parts of the pathogen they are designed to stave off.
But others focus on a sole protein. All Covid vaccines target a single antigen, a part of the SARS-CoV-2 virus known as the spike protein. Most flu vaccines effectively target a single antigen, the hemagglutinin protein on the exterior of flu viruses. And vaccines against respiratory syncytial viruses are also single antigen vaccines, targeting RSV’s F protein.
In addition to puzzling experts, Kennedy’s statement could bode poorly for multiple Covid vaccines currently under review. They are made by Novavax, Moderna, and Pfizer, along with its partner BioNTech.
Beyond the pending Novavax approval, the FDA must in the coming weeks advise Covid vaccine manufacturers on how to update their shots for the 2025-2026 respiratory season.