A new perspective underscores the effectiveness of wearing a mask — even indoors, even if you’re staying six feet apart
In a perspective published Wednesday in the journal Science, a group of scientists write that masks are not only helpful but necessary to combat the spread of the virus from people without symptoms.
Here’s the deal: Respiratory infections like Covid-19 are spread through droplets and aerosols that contain the virus that are expelled from people who have the illness. This can include while talking, coughing, sneezing, and yes, breathing.
A major issue with the current pandemic, the researchers point out, is a large proportion of Covid-19 cases are spreading from people who do not show or feel any symptoms of the virus (also referred to as people who are asymptomatic).
It’s much harder to control an outbreak that can spread so easily from people who do not feel sick. The researchers point out that people with Covid-19 can be highly contagious before any symptoms occur. Covid-19 has an incubation period of up to 14 days, with a median onset of symptoms of around five days. An example they cite is the spread in Wuhan, China, where it’s estimated that people who were asymptomatic could be responsible for up to 79% of infections.
This is why testing is so important, and why mask wearing is also important.
Here’s some more bad news, from the authors: “Increasing evidence for SARS-CoV-2 suggests the [six feet] WHO recommendation is likely not enough under many indoor conditions where aerosols can remain airborne for hours, accumulate over time, and follow air flows over distances further than [six feet].”
Even outdoors, they write “breezes and winds often occur and can transport infectious droplets and aerosols long distances.” People without symptoms who are highly contagious and are speaking and exercising could still release infectious droplets that can be picked up. However, it’s important to note there is very little data on Covid-19 transmission outdoors.