Pfizer Inc. announced that the first participants have been dosed in a Phase 1 clinical trial to evaluate the safety, tolerability, and immunogenicity of a single dose quadrivalent mRNA vaccine against influenza in healthy adults. Pfizer’s mRNA influenza vaccine program is the first in a planned wave of programs leveraging mRNA technology for influenza. Beyond influenza, the company plans to explore mRNA in other respiratory viruses, including medically appropriate vaccines combinations that could provide protection against more than one respiratory virus, as well as expand to develop mRNA technology in oncology, and genetic diseases.
“Since 2018, we have been working to develop a potential mRNA influenza vaccine, driven by our deep understanding of infectious diseases and our extensive experience in researching, developing and implementing new vaccine technologies to help prevent them,” said Kathrin U. Jansen, Ph.D., Senior Vice President and Head of Vaccine Research & Development at Pfizer. “The COVID-19 pandemic allowed us to deliver on the immense scientific opportunity of mRNA. Influenza remains an area where we see a need for vaccines which could result in improved efficacy in any given season, and we believe mRNA is the ideal technology to take on this challenge to transform global health outcomes.”
Conventional seasonal influenza vaccines are generally developed by growing the virus in chicken eggs or mammalian cells, which are inactivated and processed to be made into a vaccine. This process faces multiple challenges, including producing immunogenic antigens, keeping up with virus strain changes, and alterations in the vaccine antigens during production. With circulating influenza strains continually changing, predicting the best match for the next season’s vaccine is difficult for global health experts as those strains are chosen more than six months before the start of the influenza season that they target in the Northern Hemisphere.
Even when the vaccine strains match circulating influenza virus strains well, current seasonal vaccines typically confer 40% to 60% protection against circulating strains, with even lower protection in years with poor matching of strains. Influenza causes approximately 5 million cases of severe illness and up to 650,000 deaths worldwide every year.
mRNA-based influenza vaccine design requires only the genetic sequence of the virus. The flexibility of mRNA technology and its rapid manufacturing could potentially allow better strain match, greater reliability of supply, and the potential opportunity to improve upon the efficacy of current flu vaccines. Furthermore, in a pandemic influenza situation, mRNA technology could allow rapid, large-scale manufacturing of effective vaccines.