Washington University researchers reported evidence that an mRNA flu shot may protect against influenza better than a traditional flu shot, based on a small study that found a stronger immune response in the mRNA group. The findings appear in Nature Immunology.
The study is drawing attention now because it adds fresh momentum to a technology that has already changed vaccine development. Drugmakers introduced the first widespread mRNA vaccines during the coronavirus pandemic, and the COVID immunizations remain the only mRNA vaccines currently on the market.
Hanover Matz, who worked on the research, said mRNA-based vaccines give cells the genetic instructions to make a viral protein and then train the immune system to respond. In this study, the team compared Moderna’s mRNA vaccine with the traditional flu shot by looking at the contents of patients’ lymph nodes, where immune cells gather to learn how to fight infection.
The numbers were small, but the difference was clear enough to catch the eye. In 13 people who got the mRNA flu vaccine, five developed a germinal center response in their lymph nodes. None of the 15 people who received the traditional flu vaccine showed that response. The study also suggested the immune response from the mRNA vaccine may last longer and could protect against more strains of flu.
That possibility matters because influenza is constantly changing, and vaccine makers spend each season trying to match the strains that are circulating. Matz said an mRNA vaccine could be easier to update if the virus shifts in the middle of a season, giving scientists a faster way to respond to a mismatch. He said that kind of flexibility would make it much easier to deploy a revised vaccine when the flu moves.
For now, though, the promise of the platform runs ahead of what is actually available. A committee from the federal Food and Drug Administration recommended this summer that the agency approve Moderna’s mRNA vaccine for older adults, but the timing of any final action has not been disclosed. That leaves the field in an awkward place: the science is advancing, the regulatory path is moving, and the only mRNA vaccines on the market are still the ones made for COVID.
Matz said there has been uncertainty in recent years about the future of mRNA-based vaccines, a concern sharpened by Health and Human Services Secretary Robert F. Kennedy Jr.’s skepticism of vaccines and by hundreds of millions of dollars in canceled research funding for mRNA projects. Even so, he said the science is there and researchers are still eager to push ahead. For mRNA flu shots, the next step is not whether they can generate an immune response. It is whether FDA action finally turns that response into a vaccine people can get.
