Pfizer Begins Trial of mRNA-based Flu Vaccine

The first participants have been dosed in Pfizer’s phase 1 clinical trial to evaluate the safety, tolerability, and immunogenicity of a single dose mRNA vaccine against influenza in healthy adults. The trial will evaluate the safety, tolerability, and immunogenicity of the vaccine in healthy adults 65 to 85 years of age, with a quadrivalent influenza vaccine as a control.

Conventional seasonal flu vaccines are developed by growing the virus in chicken eggs or mammalian cells, which are inactivated and processed to be made into a vaccine. 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. mRNA-based influenza vaccine design requires only the genetic sequence of the virus.

The flexibility of mRNA technology could potentially allow better strain match, greater reliability of supply, and the potential opportunity to improve upon the efficacy of current flu vaccines, Pfizer officials said.

Kathrin U. Jansen, Ph.D.

“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 that 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,” Kathrin U. Jansen, Ph.D., senior vice president and head of vaccine research & development at Pfizer, said in a statement.

The vaccine being studied will encode World Health Organization recommended strains. After initial testing of vaccine candidates encoding individual strains, multivalent combinations are planned to be tested.

In 2018, Pfizer signed a collaboration agreement with BioNTech under which Pfizer will develop and commercialize mRNA-based influenza vaccines

Pfizer’s mRNA influenza vaccine program is the first in a planned wave of programs leveraging mRNA technology for influenza, other respiratory viruses, oncology, and genetic diseases.

Worldwide, flu results in about 3 to 5 million cases of severe illness, and about 290,000 to 650,000 deaths, according to the World Health Organization.