These updated recommendations, announced on Friday, are a shift from what WHO previously advised on masks, which was to not wear them if you are not sick or not caring for someone who is sick, in an effort to keep masks available for health workers.
“In areas with widespread transmission, WHO advises medical masks for all people working in clinical areas of a health facility, not only workers dealing with patients with Covid-19,” WHO Director-General Tedros Adhanom Ghebreyesus said during a media briefing in Geneva on Friday.
“Second, in areas with community transmission, we advise that people aged 60 years or over, or those with underlying conditions, should wear a medical mask in situations where physical distancing is not possible,” Tedros said, and third, “WHO advises that governments should encourage the general public to wear masks where there is widespread transmission and physical distancing is difficult, such as on public transport, in shops or in other confined or crowded environments.”
Tedros added that the new guidance was updated based on evolving evidence.
“Our updated guidance contains new information on the composition of fabric masks, based on academic research requested by WHO,” Tedros said.
Fabric masks encouraged when physical distancing is difficult
WHO recommends that where there is widespread transmission, limited capacity to contain Covid-19 outbreaks and physical distancing of at least a meter can not be achieved, then governments should encourage their public to wear a fabric mask, Maria Van Kerkhove, WHO’s technical lead for coronavirus response and head of the emerging diseases and zoonoses unit, told CNN.
“What we are encouraging is that in situations where you have intense transmission, in situations where you can not do physical distancing, that a fabric mask should be worn — can be worn, should be worn — it’s something that needs to be considered very seriously,” Van Kerkhove said.
The new guidance recommends for these fabric masks — which can be homemade — to be at least three layers: an inner layer of an absorbent material such as cotton; a middle layer that acts like a filter or barrier, such as non-woven material polypropylene; and an outer layer of a non-absorbent material, such as polyester or polyester blend.
Van Kerkhove said to avoid materials that may be silk, stretchy or porous.
“What we are trying to do with the guidance that we’re putting out is to provide some parameters on, if you’re going to use a fabric mask, here are the best fabrics that you can use based on the evidence that we have,” Van Kerkhove said, adding that other guidance, such as maintaining physical distancing and frequent handwashing, remains important too.
“We feel very strongly that masks alone are not enough and we’re worried that people thinking that if they put on a mask, a homemade mask or a fabric mask, that they’re fully protected against this virus and they’re not,” Van Kerkhove said. “So we want to ensure that people still do physical distancing, people still adhere to the measures that their leaders are telling them to adhere to, and the bottom line is that anyone ill, anyone who is feeling unwell, should already be at home.”
In general, more research is needed to determine how effective fabric masks are at both preventing the mask-wearer from possibly spreading Covid-19 and protecting the mask-wearer from possibly catching the disease.
“The thing that needs to be understood about a mask is that it’s a barrier. So it can be used both for a barrier for somebody who’s wearing it. It can be used as a barrier for somebody who’s looking at the person who’s wearing it,” Dr. April Baller, WHO medical officer in infectious prevention and control, told CNN.
With a fabric mask, “right now we only know that it provides a certain level of barrier, but we don’t know if that’s enough to prevent,” Baller said. “With the data that there is available right now, we know that it provides some barrier, but we don’t know if it’s to the extent that it can be used for prevention.”
Guidance for health workers and caregivers
WHO also has new guidance for all health workers and caregivers in communities where there has been a lot of Covid-19: Those who work in clinical areas should wear a medical mask throughout their shift while in clinical areas — apart from eating, drinking and changing masks when necessary after caring for a patient.
“A lot of the transmission that’s happened is transmission that’s happening in the community and one of the concerns is that what’s happening in the community can be brought into the health facility,” Baller said. “It is definitely strategic and it’s looking at trying to address some of the transmission that could be happening and then at the same time ensuring that the health workers feel confident no matter what type of patients they’re seeing within the health facility.”
The updated guidance builds on previous recommendations that WHO made around caring for Covid-19 patients and wearing medical masks — including surgical masks and N95 respirators, which must be fitted to the faces of health care workers to protect them during certain procedures — along with other personal protective equipment.
“The reason that we’re updating the guidance is that WHO continuously looks at all available evidence on a variety of topics — including how this virus is transmitted, how different masks are used in different settings, including health care facilities and outside of health care facilities,” Van Kerkhove said.
“What we’ve done is we’re incorporating new research findings and we are providing more practical advice to decision-makers on how to use masks as part of a comprehensive package of measures to suppress transmission and save lives,” Van Kerkhove said. “So our goal fully remains suppressing transmission and save lives — and masks are part of that package of interventions.”
Masks don’t replace other public health measures
Wearing face masks is an “altruistic act” and primarily a tool for “source control” in the community — in which the practice is more about protecting others if you are infected than protecting yourself, Dr. Mike Ryan, WHO executive director of health emergencies programme, said Friday.
Ryan added that wearing masks needs to happen alongside other elements such as “case finding, cluster investigation, widespread testing, isolation of cases and quarantining of contacts.”
WHO’s updated guidance recommends masks be used as part of a “comprehensive package” to help curb the spread of Covid-19, which includes physical distancing, frequent hand washing, people who are sick self-isolating at home, suspected cases getting tested, and their contacts being traced.
However, in situations when physical distancing is not possible, such as using public transportation, masks can help reduce the risk of spreading the virus, Ryan said.
“Let me also emphasize, if you are sick with a fever, with a cough and are sneezing, you should not be in public, you should be seeking the care of a medical professional and seeking a Covid-19 test,” Ryan said, adding that with a positive test result you need to be isolated and all contacts need to be traced.
“We need to be very, very, very careful that masks are not seen as an alternative to the other public health measures that are so desperately needed.”