In a report published in a recent issue of the journal Cell, researchers argued that a refocus of anti-influenza efforts may be needed, with the protein neuraminidase cited as a potentially important point for decreasing flu severity and infection alike.
Historically, flu vaccines have been based on the protein hemagglutinin. Yet teams led by Patrick Wilson of the University of Chicago Medicine and Florian Krammer of the Icahn School of Medicine at New York City’s Mt. Sinai Hospital say that neuraminidase has a role to play as well. While hemagglutinin allows flu to attach to hosts’ cell membranes and get inside, neuraminidase is what helps that virus then escape the original cell and infect more.
Wilson and his team argue that placing greater emphasis on the comparatively neglected protein, neuraminidase, could substantially decrease infection rates and reduce disease severity for those infected with the virus.
“Hemagglutinin activity has been the primary measure of influenza-vaccine efficacy for decades,” Wilson said. “But they do a poor job of stimulating the immune system to neutralize neuraminidase. Neuraminidase, one of two prime targets, has been profoundly neglected. This leaves a big hole in immunity.”
This hole could be seen in the most recent influenza outbreak, wherein the U.S. Influenza Vaccine Effectiveness survey conducted by the Centers for Disease Control and Prevention (CDC) found an effectiveness in existing vaccines of just 36 percent. For Influenza A virus, that effectiveness was still lower, at 25 percent. The preceding three seasons saw effectiveness range between 19 and 48 percent.
“Our results demonstrate that hemagglutinin should no longer be the de-facto target in influenza vaccine development efforts,” Wilson said. “We think including an improved neuraminidase component to future influenza vaccine compositions can reduce the severity of illness and decrease the frequency of community-acquired influenza infections.”