Recombinant hemagglutinin influenza vaccine provides broader spectrum protection

Influenza causes annual epidemics worldwide that pose a significant public health burden and current predominant vaccines, while the most effective means of combatting the disease, provide sub-optimal protection. New more broadly effective vaccines are an important public health need.

Influenza hemagglutinin (HA) is the principal viral surface protein that induces protective immunity to influenza infection. A recombinant seasonal influenza hemagglutinin (rHA) vaccine, recently introduced in the U.S., has demonstrated promising efficacy and safety in a number of clinical trials in adults. The immunodominant globular head of the HA protein induces antibodies that are narrowly specific to individual antigenically varied strains of influenza virus, resulting in poor affinity for antigenically drifted strains and the need for repeated annual vaccination. Broader spectrum protection may be achieved with immunity directed at more conserved viral antigens. We reviewed the data from clinical trials of the rHA vaccine conducted during seasonal epidemics characterized by antigenic mismatch between vaccine and circulating strains of influenza. Expert commentary: These data suggest that the rHA proteins produced in Lepidopteran cells offer broader-spectrum protection and result in clinical benefit.