Advice On Changing Masks and Wiping Surfaces

Here are a couple of articles about COVID-19 that I thought were worth sharing.

First, from the New York Times, an article about the often-confusing advice that we get about wearing masks. What type of mask should you wear and when should you change it?  

If I were wearing an N95 just for the weekly grocery store run, I’d probably be fine with alternating two carefully handled masks for many months as long as the elastic works and there’s no soiling. That’s not a lot of use! But if I were wearing one all day, every workday, I’d consider having one for each day and replacing them maybe every month. So that’s about five per month. Could one be really careful and make that two months? Probably.

Also it’s important to emphasize that all this doesn’t mean cloth masks are worthless. Cloth masks do really help with stopping transmission onward, from the wearer to the other people. It would be good to be able to purchase certified cloth masks with the three layers the WHO recommends,  with features like nose wires and ties that make them fit better. One can also wear surgical masks — those light, papery ones commonlyused in hospitals — with a brace to help hold them in place. Preliminary studies show those do a great job, too. It’s just that medical respirators like the N95s, KN95 (the Chinese standard), disposable K94 (the South Korean standard) and FFP2 (the European standard) do a much better job of protecting the wearer in addition to helping prevent onward transmission — because that’s what they are designed to do! Protecting the wearer is more important if, for example, someone works with other people who don’t mask up well, or if one is high-risk and can’t isolate. This is especially important with the new, more transmissible variants. But you don’t need an N95 for that outdoor walk.

Second, what about surface transmission? Do we really need to wipe down everything that comes into the house? According to Nature, probably not. 

Armed with a year’s worth of data about coronavirus cases, researchers say one fact is clear. It’s people, not surfaces, that should be the main cause for concern. Evidence from superspreading events, where numerous people are infected at once, usually in a crowded indoor space, clearly point to airborne transmission, says Marr. “You have to make up some really convoluted scenarios in order to explain superspreading events with contaminated surfaces,” she says.

Hand washing is crucial, says Marr, because surface transmission can’t be ruled out. But it’s more important to improve ventilation systems or to install air purifiers than to sterilize surfaces, she says. “If we’ve already paid attention to the air and we have some extra time and resources, then yes, wiping down those high-touch surfaces could be helpful,” she says.

Households can also ease up, says Pickering. Quarantining groceries or disinfecting every surface is going too far. “That’s a lot of work and it also is probably not reducing your exposure that much,” she says. Instead, reasonable hand hygiene, as well as wearing a mask and social distancing to reduce exposure from close contacts is a better place to focus efforts.