Further to why flu vaccines so often fail, from Jon Cohen at Science, on efforts to find out wy the flu vaccine is so “lackluster”(10% to 60& protection):
They’re questioning what was once received wisdom: that the vaccine fails when manufacturers, working months ahead of flu season, incorrectly guess which strains will end up spreading. And they’re learning instead that the vaccine may falter even when the right strains were used to make it, perhaps because of how it is produced or quirks of individual immune systems. “It’s much more complicated than we thought,” Osterholm says. “I know less about influenza today than I did 10 years ago.”
…
Danuta Skowronski, an epidemiologist at the BC Centre for Disease Control in Vancouver, Canada, instead blames mutations in the vaccine strain itself. The most common influenza vaccine contains an “inactivated” virus, which manufacturers grow in chicken eggs. As Skowronski’s team first reported in 2014, the virus can mutate while it is growing in the eggs, resulting in a vaccine unable to block circulating strains. More.
If we are on the wrong track, knowing less than we did ten years ago is a sign of progress.
Note re “lackluster”: Only so many viruses that can be safely loaded into one vaccination. What can go wrong for a retirement home, for example, is that the virus that puts the place on lockdown was not included in the annual vax.
See also: Why viruses are not considered to be alive
Another stab at whether viruses are alive
Phil Sci journal: Special section on understanding viruses
Why “evolution” is changing? Consider viruses
The Scientist asks, Should giant viruses be the fourth domain of life? Eukaryotes, prokaryotes, archaea… and viruses?
and
Are viruses nature’s perfect machine? Or alive?