Good news out of that Missouri Great Clips where both the stylists and clients all wore masks and stylists were symptomatic. All 140 clients (46 who tested negative) have no symptoms after 2 weeks quarantine. I don't know if you can expect 0% transmission with masks but definitely think it's a good sign masks reduce transmission even in close contact somewhat prolonged contact.
From the article:
Two Missouri hairstylists who worked while
they had coronavirus did not infect the 140 clients they served even though they had symptoms at the time, local health officials said.
The clients and the stylists all wore face coverings, and the salon had set up other measures
such as social distancing of chairs and staggered appointments, the Springfield-Greene County Health Department said this week.
Of the 140 clients and seven co-workers potentially exposed, 46 took tests that came back negative. All the others were quarantined for the duration of the coronavirus incubation period. The 14-day incubation period has now passed with no new infections linked to the salon, county health officials said.
During the quarantine, those who did not get tested got a call twice a day from health officials asking whether they had symptoms related to Covid-19, said Kathryn Wall, a spokeswoman for the Springfield-Green County Health Department.
County health officials called the results encouraging, and said they're looking into the case for insight on how to stop the spread and help with efforts on future research.
"This is exciting news about the value of masking to prevent Covid-19," said Clay Goddard, the county's director of health. "We are studying more closely the details of these exposures, including what types of face coverings were worn and what other precautions were taken to lead to this encouraging result."
Studies have found that
physical distancing and the use of a mask are the two best ways to prevent coronavirus transmission.
This month, a study published in the Lancet medical journal found people should
stay six feet apart and wear face coverings. It said the chance of transmission without a face mask was 17.4%, while that fell to 3.1% when a mask was worn.
https://www.cnn.com/2020/06/11/us/missouri-hairstylists-coronavirus-clients-trnd/index.html