Over a year after the meme was posted, Facebook fact-checks meme that compares mask-wearing to putting up a chainlink fence to keep mosquitos away: A user posted a meme that depicts a woman who is wearing a mask and a man who is maskless on either side of a fence. The woman says: "I'm wearing this mask to keep the virus out of my body," and the man responds "I'm building this fence to keep the mosquitos out of my yard." Purported screenshots of the post show that it was originally published in June of 2020 but the fact-checker only recently fact-checked the post. Lead Stories admits that the meme is a joke but cites a study published by the Proceedings of the National Academy of Sciences of the United States of America (PNAS) which claims that mask-wearing aids with "source control to reduce community transmission" of COVID-19. Podcaster and journalist Liz Wheeler reported that the study "did not account for the natural decrease [in COVID-19 infection]" and Wheeler, Buzzfeed, and Vox all reported that over 40 scientists called for the study to be withdrawn. Fact-checked posts lose exposure on Facebook feeds as they are negatively affected by the platform's algorithm. According to Facebook, users fail to click through a fact-check interstitial to see the post 95% of the time.