Wearing face masks at home might help ward off COVID-19 spread among family members

https://www.eurekalert.org/pub_releases/2020-05/b-wfm052720.php

News Release 28-May-2020
BMJ


Wearing face masks at home might help ward off the spread of COVID-19 infection among family members living in the same household, but only before symptoms develop, suggests a study of Chinese families in Beijing, accepted for publication in BMJ Global Health.

This practice was 79% effective at curbing transmission before symptoms emerged in the first person infected, but it wasn't protective once symptoms had developed, the study shows.

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Daily use of disinfectants, window opening, and keeping at least 1 metre apart were associated with a lower risk of passing on the virus, even in more crowded households.

But daily contact and the number of family members wearing a face mask after the start of symptoms in the first person to develop them were associated with a heightened risk.

Of all the behavioural and hygiene factors, four were significantly associated with secondary transmission of the virus.

Diarrhoea in the first person to become infected and close daily contact with them increased the risk of passing on the virus: diarrhoea was associated with a quadrupling in risk, while close daily contact, such as eating meals round a table or watching TV together, was associated with an 18-fold increased risk.

Frequent use of bleach or disinfectants for household cleaning and the wearing of a face mask at home before symptoms emerged, including by the first person to have them, were associated with a reduced risk of viral transmission.

A face mask worn before symptoms started was 79% effective, and disinfection 77% effective, at stopping the virus from being passed on.

The authors acknowledge some limitations to their study: telephone interviews are subject to recall and the strength of household disinfectants and bleach used wasn't recorded.

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