​New information and guidance have emerged on how face masks prevent the spread of COVID-19 and which ones provide the best protection. Masks with valves are ineffective; neck gaiters, worn around the neck and pulled up over the mouth and nose when needed,

may not work either. The U.S. Centers for Disease Control and Prevention also discourages the use of clear plastic face shields as a substitute for masks. Despite some pushback, face masks are now mandated in many