New H1N1 stem discovery could lead to universal flu vaccines

Researchers with the University of British Columbia may have found a way to create vaccines that attack most flu viruses at once and do away with the need for seasonal flu vaccinations.

John Schrader, the leader of the study and the director of UBC's Biomedical Research Center, and his colleagues determined that the 2009 H1N1 swine flu vaccine triggers antibodies can protect against multiple influenza viruses, including the H5N1 avian flu strain. The team determined that the 2009 pandemic H1N1 vaccine induced antibodies that attack the stem of the flu virus's hemagglutinin protein.

"The flu virus has a protein called hemagglutinin, or HA for short. This protein is like a flower with a head and a stem," Schrader said. "The flu virus binds to human cells via the head of the HA, much like a socket and plug. Current flu vaccines target the head of the HA to prevent infections, but because the flu virus mutates very quickly, this part of the HA changes rapidly, hence the need for different vaccines every flu season."

By triggering antibodies that attack the stem of the virus instead of the head, universal flu vaccines could be developed, stopping seasonal influenza in its tracks.

"This is because, rather than attacking the variable head of the HA, the antibodies attacked the stem of the HA, neutralizing the flu virus," Schrader said. "The stem plays such an integral role in penetrating the cell that it cannot change between different variants of the flu virus."

Schrader's team has evidence demonstrating that a vaccine with a mixture of influenza viruses not circulating in humans but in animals should have a similar effect to the antibodies generated by the 2009 pandemic H1N1 virus.