For a long time, it was said that masks would not help in the fight against Sars-CoV-2. A study proves the opposite: they work – especially with coronaviruses.
While wearing masks has long been the order of the day in Asia, experts such as WHO emergency director Michael Ryan advised until last week not to wear a face mask if you weren’t sick yourself. Daniel Koch from the Federal Office of Public Health BAG also commented accordingly.
But meanwhile, there has apparently been a rethink. For example, WHO Director-General Tedros Adhanom Ghebreyesus announced that they would now like to check whether “wearing a full face mask can contain contagion”.
Scientific virus counting
This is exactly what researchers from China have already done. For their study published in the renowned journal Nature Medicine, the team led by Benjamin Cowling from the University of Hong Kong investigated how many viruses leave the mouth or nose during breathing and coughing.
For this purpose, special funnels were set up around the test persons’ heads, which recorded everything the test subjects gave for 30 minutes. 124 of them wore a simple mouth-nose mask, 122 wore no protection. All participants suffered from either a respiratory infection caused by flu, rhino or seasonal coronaviruses.
Significant filter effect
The evaluation in the laboratory showed that the filter effect of the masks was considerable. “In 111 people, the masks reduced the virus in respiratory droplets and aerosols,” said Cowlings colleague Nancy Leung Hiu-lan in a message. These were infected with corona and flu viruses. Coronaviruses were therefore never detected in the air we breathe, whereas this was regularly the case without a face mask. “The masks, on the other hand, could not reduce the emission of rhinoviruses.”
Although only harmless coronaviruses were examined in the study, but not the trigger of the current pandemic, Cowling assumes that the findings can also be transferred to the COVID 19 pathogen: They are closely related and could, therefore, be considered physically – behave very similar to the seasonal coronaviruses.
Protect fabric masks too
But what if you want to leave the hygiene masks to the doctors and nursing staff in view of the increasingly scarce stocks? Then self-sewn masks should also do it, as Cowling told the Reuters news agency: “In my opinion, fabric or cotton masks should also protect, if a little less than a properly worn surgical mask.”