Face masks block up to 90 per cent of coronavirus but can’t stop transmission entirely, Japan study finds
- Researchers at the University of Tokyo used a pair of mannequin heads for their tests – one to wear the masks and the other to ‘cough’ coronavirus
- They found that even when an N95 mask, used by medical professionals, was fitted to the face with tape, some virus particles still sneaked in
Japanese researchers showed that masks can offer protection from airborne coronavirus particles, but even professional-grade coverings can’t eliminate contagion risk entirely.
Scientists at the University of Tokyo built a secure chamber with mannequin heads facing each other. One head, fitted with a nebuliser, simulated coughing and expelled actual coronavirus particles. The other mimicked natural breathing, with a collection chamber for viruses coming through the airway.
A cotton mask reduced viral uptake by the receiver head by up to 40 per cent compared to no mask. An N95 mask, used by medical professionals, blocked up to 90 per cent. However, even when the N95 was fitted to the face with tape, some virus particles still sneaked in.
When a mask was attached to the coughing head, cotton and surgical masks blocked more than 50 per cent of the virus transmission.
“There was a synergistic effect when both the virus receiver and virus spreader wore masks,” the researchers wrote in a study published on Wednesday.