Wearing a face mask in this place can reduce transmission of COVID-19 by 79%

Though most of the guidelines for mask-wearing have been about when you leave the house and go out into the world and interact with others a new study sheds light on wearing it in the home. New research published in BMJ Global Health finds that wearing masks at home is 79% effective at preventing the spread of COVID-19 amongst family members. However, in order for it to work, you need to wear it before any of the people in your home start showing symptoms.

This conclusion was come to after researchers sent a survey to 460 people from 124 families in Beijing, China asking them questions about their hygiene practices and behaviors during the pandemic.

The study defined family as people who had lived with a sick person in a house for four days before and more than 24 hours after their symptoms started showing. Most families had four members (but as little as two and as many as nine) and they included children, parents, and grandparents.

They found that nearly 25% of family members would become infected with COVID-19 within two weeks once one member became sick. However, if both the sick person and the other family members wore a mask before symptoms were shown, they displayed a 79% reduction transmission rate. “The results suggest that community face mask use is likely to be the most effective inside the household during severe epidemics,” the scientists wrote.

However, the researchers emphasized the masks had to be worn before symptoms were shown in order to be effective. They said this practice could be especially useful for families who have someone working in healthcare who has a higher potential exposure rate to the virus.

The study also found using bleach or disinfectant in cleaning the house with families was 77% effective in reducing transmission.