This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A new nanoparticle vaccine could one day give patients immunity to the flu with fewer trips to the doctor and without requiring health officials to correctly guess which flu strains will become dominant each year. Mice given the vaccine, developed at University of Michigan Engineering, were protected against three different strains of flu, according to a study to be presented Aug. 24 at the American Chemical Society's fall 2026 conference.
The team achieved broader protection by targeting a virus protein that mutates more slowly than the main proteins our bodies recognize on inactivated flu viruses. Current flu vaccines must include a mix of three or four flu variants to achieve the same level of protection, and even then, they are only 30% to 60% effective. "Our goal is to develop a broadly protective and more effective flu vaccine, so you don't have to get a flu shot every season," said Fei Wen, U-M professor of chemical engineering and the corresponding author of the study.
"Eventually, with enough effort and research, we believe that you might need one shot to be protected for life." When we get flu shots, our immune systems confront inactivated flu viruses injected into our arms. The main protein they detect is hemagglutinin, which makes up 80% of the virus's surface. But the immunity is temporary because hemagglutinin is prone to mutation, with 19 versions currently in circulation and new variants emerging every few years.
Because of the variability in hemagglutinin, the World Health Organization and the Centers for Disease Control and Prevention monitor which strains are spreading so vaccine manufacturers can include them in the latest vaccines. But if a new strain emerges, the vaccines may not work as expected. In 2025, a new flu variant, called subclade K, emerged and contributed to one of the U.S.'s more severe flu seasons in recent years.
More than 320,000 flu patients were admitted to hospitals, and more than 10,000 died, according to CDC data. The swine flu pandemic of 2009 was also caused by a new flu variant. Instead of leaving our immune systems to choose which proteins to react to on an inactivated virus, the new vaccine provides one option: the M2 protein.
This flu protein is less likely to mutate because changes can make it harder for the virus to replicate. M2 is very similar across influenza A viruses, including seasonal flu, swine flu and bird flu. However, our immune systems don't naturally target M2 because there is much more hemagglutinin on viruses.
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