The Department of Health (DoH) warned that face masks with valves or slits do not block droplet transmission, hence are ineffective in preventing the spread of Covid-19. Carza was referring to the Coppermask brand of face mask that has been used and popularized in social media by influencers and other personalities. He added that the DoH is clear in its recommendation to use a properly fitted mask with no gaps in the nose, mouth and chin. In an earlier memorandum, Food and Drug Administration Director-General Rolando Enrique Domingo said face masks with valves would allow exhaled air to pass through a small filter disc that is attached to the front piece. “The presence of valves may cause a potential source of leakage permitting air to flow out of the respirator face piece,” Domingo said.

Source: Manila Times March 10, 2021 16:23 UTC