We might be one major step closer toward ending the scourge of the seasonal flu. This week, the U.S. National Institutes of Health announced the start of a phase I clinical trial testing out a potential universal flu vaccine. The safety and immune response of the experimental shot will be compared to a typical annual flu vaccine.
The candidate was developed by researchers at the NIH’s National Institute of Allergy and Infectious Diseases’ (NIAID) Vaccine Research Center. It’s a mRNA-based vaccine, much like the first generation of covid-19 vaccines. The NIH is conducting the trial in conjunction with Duke University in North Carolina; they plan to enroll up to 50 healthy volunteers between the ages of 18 and 49.
The volunteers will be divided into several groups. Three groups will receive one of three dosages of the vaccine, in order to figure out an optimal dose. Once that’s figured out, a fourth group will be given this dose. A fifth group will act as a sort of control and will be given the standard seasonal flu vaccine, which provides protection against the four strains predicted to be in circulation during the current season. Following vaccination, the volunteers will be monitored for up to a year.
The seasonal flu remains a serious public health threat in America. Prior to the arrival of covid-19, it was often the single deadliest infectious disease seen annually in the country. Each year from 2010 to 2020, for instance, the flu is estimated to have killed between 12,000 to 52,000 people and hospitalized between 140,000 to 710,000. Millions of Americans are sickened annually, costing billions in lost wages.
The seasonal flu vaccine does prevent many of these flu-related illnesses, hospitalizations, and deaths. But its effectiveness can vary widely from year to year, depending how well scientists have predicted the upcoming season’s circulating strains. And since the influenza virus quickly mutates, any protection it provides is temporary and has to be renewed annually. So a truly universal flu vaccine—one that can induce a sustained and broad immune response to current and future flu strains—is a holy grail in medicine.
“A universal influenza vaccine would be a major public health achievement and could eliminate the need for both annual development of seasonal influenza vaccines, as well as the need for patients to get a flu shot each year,” said Acting NIAID Director Hugh Auchincloss in a statement. “Moreover, some strains of influenza virus have significant pandemic potential. A universal flu vaccine could serve as an important line of defense against the spread of a future flu pandemic.”
It will likely take years for any universal flu vaccine currently in development to reach the public even if successful. But in the best-case scenario, we may have several to pick from. In April, the Vaccine Research Center reported encouraging phase I results from a trial of a similar candidate vaccine that uses non-mRNA technology, while another NIH-led trial of a different experimental flu vaccine began last year.