Developing a universal flu shot is one of the Holy Grails of the vaccine industry. But the long research road to the marketplace will be long and littered with challenging hurdles, according to scientists from the National Institute of Allergy and Infectious Diseases.
NIAID director Anthony Fauci and Gary Nabel, director of the NIAID Vaccine Research Center, point to the process now in place to make seasonal flu vaccines to highlight some of the obstacles ahead for any development program. In a Nature Medicine commentary they note that licensing such a vaccine will require some significant innovation, including finding new ways to evaluate the efficacy of vaccine candidates in clinical trials. A universal flu vaccine "would have to elicit a type of immune response that rarely occurs naturally," they say. "A detailed understanding of flu virus structure may make such a vaccine possible.
For example, scientists have identified a region of HA's (a lollypop-shaped flu protein called hemagglutinin) stem that is shared among diverse strains, and a research group at NIAID's Vaccine Research Center recently created influenza vaccines that elicit antibodies aimed at this shared region, rather than at the quick-changing head. Animals that received the experimental vaccines were protected from a diverse array of flu virus strains."
Anyone planning a trial could sort known flu virus subtypes into three tiers based on their propensity for spurring disease. Vaccine development "might be prioritized to produce first-generation universal influenza vaccine candidates that protect against multiple virus strains within the highest priority group."
- here's the release