Death from COVID, and other pneumonic (pulmonary) diseases, can be commonly a result of secondary infection by bacteria. Our bodies are not the best at handling two different types of threats at the same time. See https://www.nature.com/articles/s41598-021-92220-0 for instance.
P.S. Note that the situation was unclear in 2020-2021 -- for instance from a quick lookup see https://pubmed.ncbi.nlm.nih.gov/34354682/. So patient management was different per region -- as it was a guess.
Same deal in Japan, every time my kid has a cold her mum takes her to the doctor and comes home with antibiotics. When I get a cold the first thing anyone asks is whether I went to the doctor yet. For what? “Medicine.”
P.S. Note that the situation was unclear in 2020-2021 -- for instance from a quick lookup see https://pubmed.ncbi.nlm.nih.gov/34354682/. So patient management was different per region -- as it was a guess.