Universal flu vaccine on the way?

Wistar Institute scientists have made a stimulating proposal, positing that providers could soon be able to stimulate the immune system to fight off multiple strains of influenza at once via sequential vaccination.

Such a discovery could spur the development of a universal flu vaccine that would be capable of shielding against influenza over a series of years rather than just seasons.

"Influenza vaccines are very safe and provide good protection. However, we need to continuously update seasonal flu vaccines because influenza viral proteins change over time," said Scott Hensley, PhD, an assistant professor at The Wistar Institute and corresponding author on the study, in a news release. "Since influenza viruses are constantly changing, we all have unique pre-exposure histories that depend on when we were born and the specific types of viruses that circulated during our childhood."

Vaccination efforts on such a scale currently focus on the concept of generating antibodies against a portion of influenza that does not change significantly from year to year. Hensley and crew moved forward with this frame of thought during their own investigation.

"Our studies demonstrate that individuals that are infected sequentially with dramatically different influenza strains mount antibody responses against a conserved region of influenza virus," Hensley said. "Since we now know that pre-exposure events can influence vaccine responsiveness in a predictable way, we can begin to design vaccine regimens that preferentially elicit antibody responses against conserved regions of influenza virus."

The study examined human antibody responses to the 2009 H1N1 pandemic and found that the most effective antibodies were those that bound to epitopes or hemagglutinin (HA), a protein produced by influenza viruses. When the researchers categorized the corresponding database by age of donor, they additionally were able to conclude that a patient’s response to the aforementioned antibodies was susceptible to whether the individual had experienced previous flus of similar natures.

"We can now accurately predict how individuals will respond to the pandemic H1N1 strain based on the year that they were born," Hensley explained.

For future study, Hensley suggested sequentially vaccinating children with antigenically distinct viral strains.

"Babies are born with an immunological blank slate," he said. "We may be able to strategically vaccinate our children with antigenically diverse influenza strains to elicit antibodies against conserved viral epitopes."

The study was published in the latest edition of the Journal of Experimental Medicine.