A vaccine that induces immune responses to a wide spectrum of influenza virus strains and subtypes has produced strong and durable results in early-stage clinical trials in humans, Mount Sinai researchers have found, according to a press release.
The universal influenza virus vaccine, which produces antibodies that target the part of the surface protein of the influenza virus known to neutralize diverse influenza strains, was described in a study published in the journal Nature Medicine. This chimeric hemagglutinin (HA)-based vaccine has the potential to provide long-lived protection with two or three immunizations, eliminating the need for revaccination.
“An influenza virus vaccine that results in broad immunity would likely protect against any emerging influenza virus subtype or strain and would significantly enhance our pandemic preparedness, avoiding future problems with influenza pandemics as we see them now with COVID-19,” says Florian Krammer, PhD, Professor of Microbiology at the Icahn School of Medicine at Mount Sinai, and corresponding author of the study. “Our chimeric hemagglutinin vaccine is a major advance over conventional vaccines, which are often mismatched to the circulating strains of virus, impacting their effectiveness. In addition, revaccinating individuals annually is a huge and expensive undertaking.”
Seasonal influenza is a major public health concern, triggering as many as 650,000 deaths every year globally, according to the World Health Organization. In addition, influenza pandemics, similar to the current COVID-19 outbreak, occur at irregular intervals and can claim millions of lives. The most devastating example is the H1N1 pandemic of 1918, which caused approximately 40 million deaths.
Influenza virus vaccines – the best preventive weapon in the public health arsenal against seasonal influenza – contain three or four strains of the influenza virus that respond to the viruses circulating in the human population. Their inherent weakness, however, is that vaccine strains in the annual formulations are based on global health surveillance and predictions that are often out of sync with the strains that actually circulate, Mount Sinai said. The situation is compounded in the case of emerging pandemic viruses because these outbreaks cannot be predicted and emerge suddenly, requiring newly matched vaccines to be generated. This process requires at least six months, leaving large portions of the population vulnerable.
The chimeric HA vaccine seeks to correct this uncertainty by targeting a different part of the hemagglutinin protein, the major surface glycoprotein of the influenza virus that binds to host cell receptors. Conventional vaccines induce neutralizing antibodies that target the distal part of the hemagglutinin, known as the globular head domain.
Mount Sinai’s Phase 1 clinical trial evaluated the safety and immunogenicity of the vaccine in 65 participants in the United States and was found to produce a strong immune response that endured for at least 18 months following vaccination.
Collaborative efforts between Mount Sinai, PATH,GlaxoSmithKline (GSK), the University of Chicago Pritzker School of Medicine, Cincinnati Children's Hospital Medical Center and Duke University School of Medicine in North Carolina contributed to the testing of this vaccine candidate.
