One reason to be dubious about the potential effectiveness of the CV-19 vaccines was the unimpressive track record of the influenza vaccines. I and others were probably more hopeful than we should have been that the new mRNA approach might improve respiratory vaccine effectiveness, but no such luck. A couple of recent articles on flu vaccine effectiveness highlight the issue. The first was carried out between October of 2021 and April of 2022, during the typical peak of flu season. The study design wasn’t ideal, at seven sites patients were enrolled who came in with respiratory symptoms including a cough. People who tested positive for CV-19 were excluded and there were a large number of them. Since co-infection is often seen, not sure why they should be excluded. The nominal reason was some strong confluence between those who got vaxed for CV-19 and for flu, but so what, just do the analysis across various subgroups.
In any event, effectiveness was only around 36%, which the authors attempted to promote as beneficial. I don’t think so. Apparently, the mix of the flu vaccine missed a particular antigen which turned out to be common. And for the elderly, effectiveness was 10%. Whoopee. A very high number of people had CV-19 infections, and since there was a high percentage of CV-19 vaxed people, another sign that those vax are not particularly effective. The average age of the flu infection was 19, whereas it was 37 for CV-19. (Flu Study)
The second study was published by the CDC itself. Let me just quote the authors’ summary: “Based on data from 3636 children, adolescents, and adults with acute respiratory infection during October 4, 2021–February 12, 2022, seasonal influenza vaccination did not reduce the risk for outpatient respiratory illness caused by influenza A(H3N2) viruses that have predominated so far this season.” Hmmm, don’t think I can add to that. (CDC Study)
The limited effectiveness of the flu vax doesn’t mean some people can’t benefit from them, especially more vulnerable older people, but in the usual human biology irony, vaccines typically prompt a lesser immune response from the elderly.