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Face Masks at Home Reduce COVID-19 Risk, Study Says

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May 28, 2020 -- Are face masks moving from the street into the living room?

A study conducted in China says wearing face masks at home greatly reduces a person’s risk of catching the coronavirus -- a major escalation from the most common advice on the cloth coverings, which is that they should be worn in public when social distancing can’t be practiced.

Researchers interviewed 335 people from 124 families in Beijing between late February and late March about their households during the pandemic. Each family had one confirmed case of coronavirus. The average family had four people, and most families had three generations.

Most person-to-person transmission occurred within households, the study says. Wearing face masks in the same house was 79% effective at curbing transmission, but only before symptoms emerge. Wearing masks really wasn’t protective after the symptoms started.

The daily use of chlorine or ethanol-based disinfectant was 77% effective at curbing transmission in the household.

“This study confirms the highest risk of household transmission being prior to symptom onset, but that precautionary [non-pharmaceutical interventions], such as mask use, disinfection and social distancing in households can prevent COVID-19 transmission during the pandemic,” said a news release from BMJ Global health, the medical journal that published the study.

If the first person to become infected had diarrhea, the risk of passing the virus quadrupled, the study says. Having close daily contact with the first person infected, such as eating meals or watching television together, had an 18-fold increased risk.

Overall, the study supports “universal face mask use, not just in public spaces, but also at home,” the news release said.

Face masks are not universally advocated as a way to combat COVID-19.

The BMJ news release noted that the World Health Organization (WHO) and Public Health England haven’t endorsed the wearing of face masks indoors or outdoors because those groups don’t think there is enough evidence to support the idea. The Chinese researchers undertook their household project to see if face masks made a difference, the news release said.

Masks are becoming more accepted, and sometimes required, in the United States.

When the coronavirus first came to the United States, federal officials said face masks weren���t necessary for people who weren’t sick.

But as the number of cases rose, the Trump administration performed an about-face. In early April, the administration urged Americans to start wearing masks when they couldn’t social distance, though President Trump said he wouldn’t wear one.

Two Emory University doctors on Thursday discussed how face masks have become more important and accepted.

“We’ve come full circle on this,” Colleen Kraft, MD, associate chief medical officer at Emory University, said during a media briefing. “Initially we’ve thought that there may not necessarily be a change to the spread of the transmission with the mask, but we really feel like now that there’s an aspect of protection and an aspect of a reminder of social distancing when you are wearing a mask, so we do recommend that individuals wear masks.”

Kraft said, “My mask protects me and protects others.”

Carlos del Rio, MD, distinguished professor of medicine, epidemiology and global health at Emory University, noted that the mask “acts almost as a visual reminder that something is going on. Since you don’t see the virus, you tend to think that it’s no longer here. This is just a way of reminding ourselves that, yes, the virus is still here and I need to do something about it.”

Health experts in the United States have come out strong for masks in public, but not in the home.

"We now have really clear evidence that wearing masks works -- it's probably a 50% protection against transmission," Chris Murray, MD, director of the Institute for Health Metrics and Evaluation, or IHME, at the University of Washington, told CNN.

Anthony Fauci, MD, the nation’s top infectious disease expert, told CNN that wearing masks and washing hands “are the things that everybody should seriously consider doing.”

Local and state leaders are embracing face masks.

On Thursday, New York Gov. Andrew Cuomo said he’ll sign an executive order allowing private businesses to bar people who don’t wear face masks. “The store owner has the right to protect himself,” Cuomo said at a news briefing.

Cuomo said in mid-April that people should wear masks when social distancing is impossible, as on public transit, The New York Times reported.

And local government leaders in Los Angeles told residents that masks were mandatory in mid-May -- about the time stay-at-home rules were being eased, the Los Angeles Times reported.

Virginia Gov. Ralph Northam said on Tuesday that state residents must wear masks in public starting Friday, TV station WTKR reported.

Staff Writer Brenda Goodman contributed to this report.

WebMD Health News Reviewed by Arefa Cassoobhoy, MD, MPH on May 28, 2020

Sources

BMJ: “Reduction of secondary transmission of SARS-CoV-2 in households by face mask use, disinfection and social distancing: a cohort study in Beijing, China?"

CNN.com: “Masks seem to be working to fight the virus, even as some refuse them and US deaths near 100,000.”

WTRK.com: "Gov. Northam orders Virginians to wear face coverings in public starting Friday."

New York Times: "New York Orders Residents to Wear Masks in Public."

Los Angeles Times: “Face masks are now a mandatory L.A. accessory. Can we keep covered up?”

Carlos del Rio, MD, distinguished professor of medicine, epidemiology and global health, Emory University, Atlanta.

Colleen Kraft, MD, associate chief medical officer, Emory University, Atlanta.

 

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