First off: https://www.worldometers.info/coronavirus/

Globally, only about 1% of the 7.8B people had been infected with #Covid. Of that 1%, about 70% have recovered. Exact numbers and percents vary by nation and region/state. That said, with over a +98% uninfected rate, what's the problem?

A 70 year meta study by the US CDC concluded "... from literature published during 1946- July 27, 2018. In pooled analysis, we found no significant reduction in influenza transmission with the use of face masks..."

Oxford Centre for Evidence-Based Medicine https://www.cebm.net/covid-19/masking-lack-of-evidence-with-politics/

Norwich School of Medicine https://www.medrxiv.org/content/10.1101/2020.04.01.20049528v1

And many other medical professionals conclude they are ineffective.

In China, several children who had to wear a mask during sports classes fainted and died; the autopsies found a sudden cardiac arrest as the probable cause of death. https://www.thatsmags.com/china/post/31100/student-deaths-lead-schools-to-adjust-rules-on-masks-while-exercising

The WHO warns of various “side effects” such as difficulty breathing and skin rashes. https://swprs.org/face-masks-evidence/ The breathing issues would be why CO2 is a problem, and cardiac arrest.