Take Off Your Mask and Go Outside
April 29 | Posted by mrossol | CoronavirusWSJ 4/29/21 By Daniel Halperin and Monica Gandhi
You don’t need to wear a mask outdoors.
That applies whether you’re vaccinated against Covid-19 or not, regardless of your age, and despite the other qualifications in the Centers for Disease Control’s latest guidance, released Tuesday [4/27/21]. The only exception is in a packed setting in which social distancing is impossible, such as a political rally or a sports arena filled to capacity.
The three main Covid mitigation strategies are distancing, masks and ventilation. Accumulating evidence indicates how difficult it is to contract the virus outdoors, which is as ventilated as it gets. One modeling study estimated that ventilation outside, even with only a gentle breeze, is well over 100 times as effective as in an office, and more than 1,000-fold better than in most homes.
Documented cases of outdoor Covid-19 transmission are rare. A study in Wuhan, China, where the virus originated, used careful contact tracing and found that only one of 7,324 infection events was linked to outdoor transmission. An analysis of more than 232,000 infections in Ireland found that only one case in 1,000 was traced to outdoor transmission. An extensive review from the University of Canterbury concluded that outdoor transmission is rare and warned of “the potential impact on physical and mental health and wellbeing” of discouraging people from congregating outdoors.
Coronavirus droplets are rapidly dissipated in the air and deactivated by ultraviolet radiation, heat and humidity. That’s why the World Health Organization concluded in December that masks are unnecessary outside as long as physical distancing—which WHO defines as one meter, or around three feet—can be maintained.
Indoor dining poses a far greater Covid-19 risk than outdoor congregation does, but mask mandates don’t apply at restaurant tables because you can’t eat through a mask. That has led to the strange ritual in which people dutifully wear masks outside as they walk to a restaurant, then promptly unmask—often in a poorly ventilated room—along with people who may or may not be vaccinated.
Covid-19 hasn’t been defeated yet. Discarding pointless practices like outdoor masking and obsessive “hygiene theater” would make the continuing necessary precautions, including indoor masking, easier to accept.
Mr. Halperin is an adjunct professor at the Gillings School of Global Public Health at the University of North Carolina, Chapel Hill and author of “Facing Covid Without Panic.” Dr. Gandhi is an infectious-disease physician and professor of medicine at the University of California, San Francisco.
https://www.wsj.com/articles/take-off-your-mask-and-go-outside-11619631659?mod=opinion_lead_pos10
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