New WHO guidelines for influenza B/Yamagata strain vaccine

[Laroxe]

The latest ed. of The Lancet (Infectious Diseases) reports on the new WHO guidelines on the influenza vaccine. They now recommend that the quadrivalent vaccine should no longer contain the influenza B/Yamagata strain as it is no longer being detected in circulation. It's suggested that the non pharma logical interventions introduced for Covid 19 may have effectively stopped the wild type virus spreading. They say, "This would represent the first time that an influenza virus has been eliminated from the human population through NPIs."

The edition also discusses developments in searching for a universal influenza vaccine.
They also report on the effectiveness of the monovalent Covid 19 vaccines, suggesting they are less effective than the older bivalent formulations, there is also so info on cost effectiveness of vaccination.

Remember you can sign up for free (limited) access to the Lancet.

https://doi.org/10.1016/S1473-3099(23)00366-3
https://doi.org/10.1016/S1473-3099(23)00697-7
https://doi.org/10.1016/S1473-3099(23)00424-3

 

[Greg Bernhardt]

How common is it for viral strains to go extinct?

 

[Laroxe]

How common is it for viral strains to go extinct?

Well, we know it happens, but I doubt we will ever know how often. Really the only virus we know much about are those that cause diseases in humans and their food sources. The chances of a virus becoming extinct is heavily dependent on its hosts, and its effects on the hosts. A virus with a wide range of hosts, that is easily transmitted and has access to a non-immune population is unlikely to fail. There is however some interesting historical evidence of diseases and virus that have simply disappeared. We have encouraged the extinction of smallpox, rinderpest, and most recently SARS and there are others being targeted but its very difficult.

I suppose we could assume that extinctions happening naturally are rare but there is such a vast number of different species, who knows. The extinction of other living species, might in fact take several populations of virus with them, but evolution in virus can happen very quickly and that doesn't seem rare at all.