Face masks ‘79% effective’ in slowing COVID-19 spread at home

Wearing face masks at home can prevent pre-symptomatic transmission of the new coronavirus in households, according to a new study published in the British Medical Journal.

The findings, based on interviews with Chinese families carried out by doctors and academics in Australia, China and the U.S., suggest that “precautionary (non-pharmaceutical interventions) such as mask use, disinfection and social distancing in households can prevent COVID-19 transmission during the pandemic.”

The authors contend that the research shows wearing masks at home to be “79 per cent effective at curbing transmission before symptoms emerged in the first person infected.”

The work was led by the Beijing Centre for Disease Prevention and Control and involved the School of Public Health at the University of Nevada and the University of New South Wales’ Faculty of Medicine.

A total of 460 members of 124 Beijing families that had, at least one confirmed case of the virus, were interviewed about domestic prevention measures used before and after the onset of symptoms in a first household member to test positive.

Forty-one of the 124 families saw at least one other case of COVID-19 after a first infection.

The authors warned that the practice of mask-wearing “wasn’t protective once symptoms had developed.”

Curbing the family spread of the virus is crucial to wider containment, the authors believe – describing “household transmission in the pre-symptomatic or early symptomatic period as a driver of epidemic growth.”

“Any measure aimed at reducing this can flatten the curve,” they reported.

The role of face masks in slowing the pandemic, which has killed almost 360,000 people and infected a reported 5.8 million, has been hotly debated since the virus was first detected in China around the turn of the year, with governments issuing a variety of rules and recommendations.

The World Health Organisation advises: “if you are healthy, you only need to wear a mask if you are taking care of a person with COVID-19.”

Separately, the WHO suggests that “wearing a medical mask can limit the spread of certain respiratory viral diseases, including COVID-19.”