Raúl Ortiz de Lejarazu y Leonardo
Professor of Microbiology, scientific advisor and director emeritus of the National Influenza Centre in Valladolid
The quality of the article is good, although it is not an experimental work but a compilation, an article of articles.
The meta-analysis of the articles they publish deals with a topic that is already known: bacterial complications of influenza. Something that has been known for a long time. More than a third of the 50-60 million deaths from the 1918 pandemic flu were due to bacterial superinfections at a time when antibiotics had not been discovered. This article, an analysis of flu articles published between 2010 and 2020, summarizes and quantifies that previously known fact.
In meta-analyses what matters are the selection criteria of the articles used and the subsequent analysis.
I miss (I do not know if they have collected and prepared it for another article, it would be a pity if they did not) separating the articles in which the diagnosis of influenza is confirmed by the laboratory from those in which it is not.
It would also have been interesting to know if there are differences between the percentage of bacterial superinfections in cases of influenza A subtype H1 (affecting more young people) and those of influenza A subtype H3 (affecting more elderly people) and also between influenzas produced by type B.