Raúl Ortiz de Lejarazu y Leonardo
Professor of Microbiology, scientific advisor and director emeritus of the National Influenza Centre in Valladolid
The search for a universal influenza vaccine began in 2012-13, although there had been different approaches before that. Among the latest is trying to discover and obtain antigens (epitopes) that are present in the majority of variants of an influenza subtype (conserved epitopes). In this way a universal response can be achieved and even if the variable epitopes change, the response to the conserved epitopes will remain.
The new study is well conceived and comprehensively conducted. Science is a journal whose publications are of the highest standard.
The most important novelty is that it uses many antigens of different haemagglutinin subtypes (all existing ones including those from bats) instead of going to conserved regions of one or a few antigens. This used to be more difficult than it is now. Current mRNA vaccine platforms allow the inclusion of many mRNAs that will induce many different proteins giving a multivalency and breadth of response that was not easy to achieve with protein platforms in the past.
The main limitation is that it is done in mice and ferrets, very good animal models for flu, but animal models. So with sarcasm (always healthy in science), mice and ferrets around the world should congratulate themselves because they now have a universal flu vaccine for themselves.
In all seriousness, there is a long, sometimes insurmountable, way to go from the animal model to humans. The type of response, the extent of the response, the persistence, etc. are not similar.
The first [phase 1] human trial of a universal influenza vaccine was published two years ago, but people were enraptured by the new coronavirus.