Masks Reduce the Risk of Coronavirus Infection by almost Half

What are the benefits of wearing mouth and nose protection in public spaces? Scientists from Mainz are now providing further evidence of the benefits of this preventive measure in a new study.

The benefits of wearing mouth and nose protection in public spaces - unlike wearing medical masks in clinics - are repeatedly and critically questioned. A group of German scientists has now compared different regions in Germany in which the mask requirement was introduced at different times.

To do this, the scientists looked at the rise in recorded Covid-19 cases within three weeks of the introduction of mandatory wearing. The starting point of their analysis, the results of which were published in the specialist journal "PNAS" at the beginning of December, was the city of Jena, where the wearing of face masks in public transport and shops became mandatory in early April as the first nationwide.

According to the study authors, the early introduction of face masks in Jena has led to a decrease in newly designated Covid-19 cases of around 75 percent after 20 days compared to a theoretical control group. According to the authors, a decline of over 90 percent was most noticeable in the age group 60 and older.

In order to be able to generalize the results for Jena, the results there were then compared with the infection rate in other regions that had introduced the mask requirement by April 22 (around eight percent of all German regions). This included cities such as Trier, Darmstadt, Cloppenburg and Rostock. There, the infection rate, population density, average age, proportion of senior citizens and the availability of doctors and pharmacies were similar to those in Jena.

Result: Although the average protective effect was smaller compared to that in Jena, the 47 percent reduction in Covid-19 cases was evident, as the researchers report. "That is 55 instead of 100 new infections," said Mainz economist Klaus Wilder, one of the study's scholars. "Or even more clearly: Instead of 20,000 new infections a day without masks, we would have around 38,000."

His conclusion: "Everyone should wear masks to protect themselves and others from infection." However, the influence of other behavior changes on the infection process cannot be completely ruled out. One such signal effect would be that people generally behave more cautiously in the presence of masks.