WEDNESDAY, Jan. 15, 2020 (HealthDay News) -- An experimental flu vaccine gave mice long-lasting protection against six different flu virus strains, researchers report.

The nanoparticle vaccine contains two major influenza proteins -- matrix protein 2 ectodomain (M2e), and neuraminidase (NA) -- and protected the mice for up to four months.

The results suggest that this combination has potential as a universal flu vaccine or component of such vaccines, said researchers at Georgia State University's Institute for Biomedical Sciences.

"This nanoparticle antigen combination conferred mice with strong cross-protection," said study first author Ye Wang, a biology Ph.D. student at the institute.

"It can protect mice from different strains of influenza virus. Each season, we have different flu strains that affect us. By using this approach, we hope this nanoparticle vaccine can protect humans from different strains of influenza virus," Wang said in a university news release.

A universal flu vaccine could prevent flu epidemics and pandemics, and eliminate the need for vaccinations each season, according to the researchers. But animal research doesn't always pan out in humans.

The investigators noted that the flu virus protein M2e is found in all flu virus strains, with each strain having a very similar version, and the protein has mutated very slowly over time. The protein NA is found on the surface of flu viruses and has also mutated much slower than other flu proteins.

According to study co-author Gilbert Gonzalez, "It's important to mention that a lot of flu vaccines haven't focused on NA before." Gonzalez is lab manager in the Institute for Biomedical Sciences.

"NA is becoming a more important antigen for influenza vaccine research. Previously, it had been ignored or discounted because hemagglutinin (HA) is much more dominant. When you get a flu infection, your body reacts to the HA," he explained.

However, the HA protein mutates very quickly, which is why seasonal flu vaccines must be changed every year, the study authors noted.

The mice in this study received intramuscular injections of the vaccine. The next phase of this research is to use the vaccine in microneedle patches for skin vaccination.

The study was published recently in the journal Advanced Healthcare Materials.

More information

The U.S. Centers for Disease Control and Prevention has more on flu vaccines.