A team of US scientists has successfully tested a prototype mRNA vaccine that contains antigens from all 20 known influenza A and B virus subtypes in animal models and could serve as the basis for a universal vaccine.
As detailed this Thursday in an article published in the journal Science, the vaccine produced high levels of cross-linked and subtype-specific antibodies in mice and ferrets and was successful in protecting the animals from disease symptoms and death after infection with strains from the flu.
Achieving a universal flu vaccine is one of the biggest global health goals, as it is difficult to predict each year which flu strain will cause the next pandemic.
In Spain alone, in 2020, this virus, which is particularly serious in people over the age of 64 and in risk groups, caused more than 600,000 cases, 1,800 ICU admissions and 3,900 deaths, according to the Carlos III Health Institute.
Unlike other prototypes that contain a small set of antigens shared between virus subtypes, this vaccine includes specific antigens for each subtype.
Inspired by the success of RNA vaccines against SARS-CoV-2, the team led by Claudia Arévalo, of the University of Pennsylvania, has prepared 20 different mRNAs encapsulated in nanoparticles, the same technology used by Moderna to develop its vaccines against SARS- CoV-2.coronavirus.
Each of the RNAs encoded a different hemagglutinin antigen, a highly immunogenic flu protein that helps the virus enter cells, the study said.
Antibody levels were nearly stable four months after vaccination in mice.
Multivalent protein vaccines produced using more traditional methods elicited fewer antibodies and were less protective than the multivalent mRNA vaccine in animals, according to the study.
For Adolfo García-Sastre, director of the Institute for Global Health and Emerging Pathogens at Mount Sinai Hospital in New York and author of several patents for flu vaccines in clinical development, the study is “very interesting”, according to the statements collected from Science. Media Center (SMC).
The study “demonstrates the ability to develop multivalent mRNA vaccines that can immunize against 20 or possibly more different antigens simultaneously. In this case, influenza virus antigens encompass all possible influenza virus subtypes and variants.” “. influenza, including those with pandemic potential.
Current flu vaccines don’t protect against viruses with pandemic potential, but this vaccine, “if it works well in people, it would.”
In any case, despite being a very promising preclinical study suggesting a protective capacity against all subtypes of influenza viruses, “we cannot be sure until clinical trials are carried out on volunteers,” concludes the Spanish researcher.
Also, in a related “Perspective” published in Science, Alyson Kelvin and Darryl Falzarano of the University of Saskatchewan, Canada, warn that “questions remain about the regulation and approval path for such a vaccine targeting viruses with pandemic potential but not currently in human circulation.
