Universal Flu Vaccine Enters Clinical Trials in Humans

Scientists are moving closer to creating a universal flu vaccine. The National Institutes of Health (NIH) announced on Tuesday that a universal flu vaccine has moved to phase I clinical trials, where scientists will test for human safety and appropriate dosage sizes.

Researchers will administer the vaccine candidate in up to 100 healthy volunteers between 18 and 55 years old, reports Ed Cara for Gizmodo. Before moving to phase I, the shot was tested in mice and ferrets. Researchers found that the shot protected small mammals from lethal doses of six different flu strains, showing the promise of a universal vaccine against the flu. The study results from the mice were published in bioRxiv, a preprint server that has not received peer-review yet, in September 2021. 

The vaccine, known as BPL-1357, was developed by scientists at the National Institute of Allergy and Infectious Diseases (NIAID) and contains four strains of non-infectious, chemically inactivated avian influenza thought to be not highly pathogenic, per a statement. 

Current flu vaccinations cover multiple strains but must be updated yearly and only provide modest protection against the flu due to the influenza virus’s ability to rapidly evolve, Gizmodo reports. Each year, scientists must make predictions on the genetic background of upcoming flu seasons, based on previous year’s infection data and infections going on in other parts of the world. The influenza virus’s adaptability to a variety of animals—dogs, horses, seals, birds, among others—means “these viruses are comprised of a broad array of different genotypes of variable and often unpredictable human pathogenicity,” the researchers wrote in the September bioRxiv paper.

Another issue with current flu shots is that they do not produce an immune response in mucus-filled regions like the nose, throat and lungs. 

BPL-1357 can be delivered via a nasal spray or intramuscularly with a shot. In one group for the vaccine trials, participants will receive the first dose of the candidate vaccine intramuscularly and then receive a placebo nasal spray. Another group of participants will receive a placebo shot and the actual vaccine as a nasal spray. A statement explains that the last group will receive both a placebo nasal spray and shot.

“With the BPL-1357 vaccine, especially when given intranasally, we are attempting to induce a comprehensive immune response that closely mimics immunity gained following a natural influenza infection,” says Matthew Memoli, a NIAID investigator leading the vaccine trial, in a statement. “This is very different than nearly all other vaccines for influenza or other respiratory viruses, which focus on inducing immunity to a single viral antigen and often do not induce mucosal immunity.”

The study will last seven months, and each participant will be required to return to the clinic seven times to provide blood samples and nasal swabs. Researchers will then take these samples to characterize and detect any immune responses, a statement explains. The phase I trials allow researchers to see if the vaccine can induce a wide and durable response against the flu virus in people, per Gizmodo, as opposed to the often incomplete protection offered by traditional vaccines that need to be received every year. Testing can also reveal which method of delivering the shot is best, either as a nasal spray or a shot in the arm.

If BPL-1357 is found to protect humans from various influenza strains, it may protect individuals from the seasonal flu as well as future emerging strains transmitted from animals, Gizmodo reports. “Influenza vaccines that can provide long-lasting protection against a wide range of seasonal influenza viruses, as well as those with pandemic potential, would be invaluable public health tools,” says NIAID director Anthony S. Fauci in a statement.

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a daily correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.