Research clearly demonstrates that wearing masks prevents the spread of COVID-19. Please see these recent articles as a couple of pieces of evidence: https://www.virginiamercury.com/2020/06/18/the-most-important-variable-that-you-can-control-vcu-research-shows-masks-can-dramatically-decrease-covid-19-deaths/. 

https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818

Masks may be uncomfortable, but I’m happy to wear a mask to make you safer and I want you to wear a mask to make me safer. Together, we can reduce the spread of COVID-19.