The researchers have investigated the effect of using a face mask as a supplement to other measures against infection with corona virus
The study of more than 6,000 Danes contributes new knowledge about the extent to which face masks protect the wearer against corona infection when the mask is used as a supplement to the authorities’ other recommendations against corona infection – including social distance, hand hygiene and isolation of patients with COVID- 19.
In the DANMASK-19 study, one half of the participants were selected to wear a surgical face mask when they were outside the home, and the other half of the participants were not to wear a mask. All participants were strongly encouraged to follow all other authorities’ recommendations regarding COVID-19. Mask use outside the health care system was unusual (<5%) in Denmark at the time.
After one month of follow-up, 1.8% of the participants in the mask group and 2.1% of the participants in the control group had an infection. The study thus does not confirm the expected halving of the risk of infection of the wearer of the mouthpiece, but the results could indicate a more moderate degree of protection of 15-20% – however, the study can not rule out that the mask does not protect the wearer.
Researchers from Copenhagen University Hospital recruited 6,024 adults who spent at least three hours a day outside their homes in a function that did not require the use of a mask. Participants should not have symptoms of COVID-19 or have previously had COVID-19. The participants came by lottery either in the mask group or in the control group, and the participants in the mask group were sent free surgical masks.