I have no medical background, but wanted to add that the prevalence of Pneumocystis colonization in the general population is approximately the proportion of cases of COVID-19 that are symptomatic (~70%). We don’t know either of these numbers with great confidence or precision, but these estimates appear consistent with your hypothesis.
Edit: additional source showing 68% of COVID-19 cases have a dry cough (page 4)
I emailed this comment and my reply to Elodie Ghedin, a molecular parasitologist and virologist at NYU for her thoughts on this. Here is her reply (posted with permission):
“Thanks for reaching out.
To my knowledge, there has not been an association of PCP with COVID-19. The percentages compared in that comment are not really comparing the same thing.
In severe COVID-19 cases there is indeed pneumonia but that’s a general term indicating inflammation due to the virus itself. It can however be followed by an opportunistic infection, mostly from bacteria.
At first blush SARS-CoV-2 is not doing anything all that different to the immune system than any other acute virus infection. ”