The Wolrd Health Organisation said it can help prevent the virus spread but stressed it must be combined with hand-hygiene and social-distancing.
The World Health Organization (WHO) on Friday broadened its recommendations for the use of masks during the coronavirus pandemic.
It is now advising that in areas where the virus is spreading people should wear fabric masks when social distancing is not possible, such as on public transport and in shops.
WHO Director-General Tedros Adhanom Ghebreyesus said people over age 60 or with underlying medical conditions also should wear masks in situations where social distancing cannot be maintained.
WHO previously had recommended that only health care workers, people with COVID-19 and their caregivers wear medical masks, noting a global shortage of supplies.
During a press briefing discussing the revised guidance, Tedros added that “masks on their own will not protect you from COVID-19” and emphasized the importance of hand-washing, social distancing and other infection-prevention strategies.
WHO also widened its mask guidance to specify that health workers in areas where the virus is spreading freely should always wear masks inside medical facilities.
Doctors working in cardiology or other wards, for example, should wear medical masks even if the facilities had no known coronavirus patients.
Maria Van Kerkhove, WHO's technical lead on COVID-19, said the updated recommendations were based on new research commissioned by the UN health agency.
Other health agencies, including the U.S. Centers for Disease Control and Prevention, have recommended for some time the wearing of masks or face coverings by the general public to slow the spread of the coronavirus.
British authorities said this week that face coverings would be compulsory on subways and other mass transit, as well as for all hospital staff and visitors from June 15.
April Baller (pictured in the above videos), a WHO infection control expert, said the type of masks recommended for the general public are fabric or cloth coverings that can be made at home.
She said part of the reason for the widening of WHO's advice on face masks was the increasing evidence that COVID-19 can be spread by people before they have symptoms.
WHO previously said that transmission from people who do not have symptoms was not believed to be a major driver of the virus pandemic.
“What (the masks) do is they prevent a person who may actually have the disease from transmitting it to somebody else,” Baller said.