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 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)