Wearing a face-mask while out-and-about on public transport, in shops and in crowded places could help protect vulnerable people from COVID-19 – according to a new systematic review from the University of East Anglia.
However, the researchers say the evidence is not strong enough to recommend widespread use of masks in the general population.
Researchers studied all existing data about whether using a face-mask reduces the spread of illnesses with COVID-19-like symptoms such as fever and cough/sore throat or other respiratory infection symptoms.
They found 31 studies that had analyzed whether wearing face masks stopped people from getting symptoms. The UEA researchers found that masks had a consistent but small protective effect – particularly in shared public spaces.
While the evidence is not strong enough to recommend widespread use of masks in the general population, the researchers say that there is enough evidence to support vulnerable people deciding to use them for short periods when in temporary higher risk situations – such as on public transport, visiting shops or in healthcare settings.
Due to the rapid-response nature of this research, it has not yet been peer-reviewed.
Study author Prof Paul Hunter from UEA’s Norwich Medical School, and an expert in infectious diseases, said: “There has been a lot of debate about whether wearing a face-mask could help protect people from COVID-19 and reduce the spread of the disease.
“We wanted to evaluate all the available evidence to see what the best advice for people is.
“We studied when respiratory symptoms appeared that were similar to COVID-19 – fever and cough or sore throat. But it’s important to remember that we have not been able to look specifically at COVID-19 because there have been no specific studies to date.”
Lead researcher Dr. Julii Brainard, also from UEA’s Norwich Medical School, said: “We found that using a face mask and other face coverings had a consistent but small protective effect against influenza-type symptoms while people are out-and-about in the community.
“People who wore masks, usually surgical grade, were less likely to get respiratory symptoms from casual exposure in the community. Something like a sneeze or cough near you would become less likely to cause infection. It’s a small reduction in risk, but might be very important to especially vulnerable people.
“Wearing masks at home also seemed to reduce the odds of well housemates become ill. The risk reduction was greatest, a 19 percent reduction, if both an ill person and their well contacts wore masks.
“The protective effect is probably small within a home setting because people have lots of repeated types of contact, so there are many ways for the germs to transmit. This is why washing hands remains so important. Washing hands well only requires 20 seconds of concentration occasionally throughout the day.
“In contrast, it is difficult to wear masks correctly for many hours over many days. They can be uncomfortable, hot, cause skin reactions or simply feel anti-social. Masks also need to be disposed of correctly to prevent transmission.
“And of course, wearing a mask interferes with things like sleep, eating and brushing teeth. It’s impossible to keep them on all the time.
“We found that wearing face masks was also not that protective during large gatherings. But something to consider is that the only studies available on mass events were based on people attending the Islamic Hajj pilgrimage to Mecca, Saudi Arabia – which is especially large and crowded and lasts for many days. It may not be comparable to other large group gatherings.
“Overall, we found that the evidence was too uncertain to support the widespread use of face masks as a protective measure against COVID-19. However, there is enough evidence to endorse the use of face masks for short periods of time by vulnerable individuals when in transient higher risk situations – such as on public transport or visiting shops.
“Although we can support vulnerable people who choose to wear masks to avoid infection, we want to remind everyone that the people who most need to wear masks, to protect us all, are health care workers. We are all in more danger from COVID-19 if health care workers cannot obtain the safety equipment they need, which could happen if community demand for face masks becomes too high.”
‘Facemasks and similar barriers to prevent respiratory illness such as COVID-19: A rapid systematic review’ is published on the preprint server MedRvix, on April 6, 2020.