New mRNA flu vaccine show promises
By
Dr. Priyom Bose, Ph.D. | Oct 15 2023
Every year, millions of individuals are infected by the seasonal influenza virus, which results in hundreds of thousands of deaths worldwide. Vaccination is an effective approach used to prevent influenza infection.
Influenza vaccines are developed using hemagglutinin (HA), a surface antigen of the virus that induces an immune response. A recent
Npj Vaccines study evaluates
the efficacy of a quadrivalent messenger ribonucleic acid (mRNA) vaccine encoding HA from four seasonal influenza strains.
Importance of influenza vaccination
Influenza is a respiratory infection that manifests in annual epidemics and sporadic pandemics. The four influenza subtypes endemic in humans are A(H1N1), B-Yamagata lineage, A(H3N2), and B-Victoria lineage. This seasonal viral infection causes up to 650,000 deaths annually worldwide.
The first influenza vaccine was developed in the 1940s by harvesting inactivated viruses from the allantoic fluid of embryonated hens' eggs. Currently, three types of influenza vaccines are available in the United States, including live attenuated influenza vaccines (LAIV), inactivated influenza vaccines (IIV), and recombinant HA protein subunit vaccines.
Although HA is highly immunogenic, it undergoes continual antigenic drift; therefore, updating vaccines based on the dominantly circulating influenza virus strain is imperative. Importantly, virus strain selection occurs six months prior to vaccine use, which creates an opportunity for a new variant to emerge and become unexpectedly dominant. A similar incident occurred between 2015 and 2016 during the Northern Hemisphere flu season.
Advantages of mRNA-based influenza vaccine
Although mRNA-based vaccines were being designed and developed for over a decade, the onset of coronavirus disease 2019 (COVID-19) accelerated the development process for its timely clinical use. Since then, millions of people throughout the world have received mRNA-based COVID-19 vaccines that effectively protect them against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the pandemic.
Compared to conventional IIV and LAIV influenza vaccines, mRNA-based vaccines have many advantages, including their
in vitro production process without the use of eggs or cell culture. The mRNA technology also eliminates the risk of viral growth-promoting mutations that might influence antigenicity.
Another advantage of an mRNA-based influenza vaccine is reduced production time compared to other vaccine types. This could be beneficial in reducing the time window between the vaccination program and virus strain selection and manufacturing.
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