Currently, influenza vaccination necessitates making and administering new and updated flu vaccines each year. This process involves having to predict which influenza strains will be predominant in the next flu season and including these strains in the vaccine formulation.

The effectiveness of the flu vaccine is usually 40-60%, though it can be much lower than this — for the 2021-2022 for example, the US CDC estimates effectiveness of just 16%. This is likely the result of a large antigenic mismatch between the strains in this season's vaccine and the strains in circulation.

There is intense interest in developing a universal flu vaccine. Such a vaccine would target conserved regions of flu — this thus would negate the need for modification from year to year and would also likely result in higher effectiveness than that of the seasonal vaccines. Recently, a universal flu vaccine candidate emerged from a Phase I clinical trial with encouraging results and the National Institutes of Health has recently launched a Phase I trial of another vaccine candidate.

This question is specifically asking about a universal vaccine against influenza type A , which is involved in most strains of the flu and historically have been the only known cause of flu pandemics.

The purpose of this question is to understand if there will be an approved universal influenza vaccine. The successful development of a universal flu vaccine would be a milestone in protecting the general population against future flu pandemics.