Collaborative research identifies broadly cross-protective vaccines for H3N2 influenza

Researchers around the world, including at the University of Rochester Medical Center (URMC), are pursuing a "universal" flu vaccine, one that would protect against most or all seasonal and pandemic strains of the flu virus.

Flu vaccines saved an estimated 40,000 American lives between 2005 and 2014, but they are not good enough.The vaccine used during the 2016-17 flu season, for example, was only 43 percent effective against the predominant influenza A H3N2 strain, and the lack of protection has been nearly as low in other years. So when its effectiveness proved disappointing, Scott Hensley, a microbiologist at the University of Pennsylvania Perelman School of Medicine, and his colleagues began to investigate. Current vaccines, which require experts to pick the flu strains that they believe are going to circulate in a given year, are typically 40 to 70 percent effective in the USA, though in some years protection is as low as 20 percent.

Dr Weaver said: "An ideal influenza vaccine would be low-cost, provide long-lasting immunity, require few immunisations and would work against all variants of the virus".

He thinks the U.S. Food and Drug Administration should more closely monitor how much viruses change during the manufacturing process, adding that the flu shot is "arguably our least effective vaccine".

Vaccines against flu are made using proteins purified from the outer layer of killed flu viruses. This year, it was a particularly bad flu season in Australia with H3N2 strains being most prevalent. This induces immune cells to make antibodies that stop foreign invaders from infecting cells, readying them to attack flu viruses when the body sees them again.

Researchers used supercomputers to analyze the genetic sequences of human H1N1 flu viruses circulating since 1918 and found variations in both the head and the stalk, although variability was highest in the head region.

But when Hensley and his colleagues studied the strain that ended up in the USA vaccine, they saw that, mysteriously, the sugar molecule had disappeared. But the researchers in Nebraska are working to develop a vaccine that uses ancestral genes from four different strains of the flu to provide long-term protection.

Conventional vaccines are reportedly less than 60% effective-and that's only when they're matched with the now circulating strain.

The flu vaccine is readily available at many locations throughout the community, including local pharmacies and health care providers' offices.

The Centers for Disease Control and Prevention said they believe vaccinations prevented about 1.9 million illnesses and 67,000 hospitalisations. However, antibodies elicited in ferrets infected with the current circulating H3N2 viral strain (that contains the new protein) and humans vaccinated with a H3N2 vaccine produced in a non-egg system were able to effectively recognize and neutralize the new H3N2 virus. The vaccine lowers infection risk-it works very well against influenza B-and may also minimize the risk of severe infection. Since it takes about two weeks for the vaccine to affect the body, the earlier in the season people get vaccinated the better their chances of being protected.