According to the New York Times, the use of tear gas on protest crowds may damage lungs and incite coughing, which may make them more susceptible to COVID-19 infections.

“I’m really concerned that this might catalyze a new wave of COVID-19,” [said Sven-Eric Jordt, a researcher at Duke University who has studied the effects of tear gas agents]. 

In research conducted by the US Army, examiners looked at the impacts of exposure that thousands of Army recruits had to the common riot-control agent known as CS gas or tear gas. The study conducted in the summer of 2012 found that the personnel in a basic training cohort had a substantially high risk of being found to have an acute respiratory illness in the days after exposure than the days before.