Wired brings up the potential of a universal flu vaccine – and the problems getting one together:
Today, independent teams reported in Science and Nature Medicine how they’ve tinkered with a piece of viral protein so it can teach immune systems—in this case, in mice, ferrets, and monkeys—to fight whole groups of viruses rather than just a single strain. “It’s a great first step in the road for generating a universal flu vaccine,” says Gary Nabel, who oversaw one of the studies as former head of the National Institutes of Health’s Vaccine Research Center.
Influenza viruses are covered in lollipop-shaped proteins called hemagglutinin, which they use to sneak into cells. Get familiar with hemagglutinin, or HA, because I’ll be talking about it a lot. The immune system produces molecules called antibodies that bind to and neutralize the head of HA, which, inconveniently for humans, mutates over and over to escape detection. The HA head varies widely across different flu viruses, but HA’s stem tends to stay the same.
In 2008, scientists discovered unusual antibodies in humans that bind to the stem of HA in many different flu strains. This was an ah-ha moment.
To be clear, neither group has created a truly universal flu vaccine, which would have to work against the entire dizzying array of influenza viruses. The highest level of classification divides the viruses into influenza A, B, and C; A includes all the biggest troublemakers. Within influenza A are group 1 and group 2, sorted based on which HAs are expressed on the viral surface. On top of that, sixteen different HA subtypes mix and match with nine subtypes of another protein called neuraminidase to create strains such as H3N2 or H5N1.
In both of these studies, the researchers began with a group 1 strain (H1N1 or swine flu) and tested whether its stem could induce immunity against another group 1 strain (H5N1 or avian flu). But creating a vaccine that would incite immunity against both group 2 and Influenza B would probably require engineering proteins to elicit different antibodies. “To be realistic, rather than calling it universal, it’s broadening protection,” says Nagel.
Still, that would be a great achievement.