A new study shows that mandatory mask wearing is the most effective measure during the Covid-19 epidemic.
On March 23 we started to urge everyone to wear masks during the Covid-19 pandemic:
Wearing a mask helps with protecting oneself but even more importantly helps to protect others. One might be carrying and spreading the disease without knowing it. We all release fine droplets when we speak, sneeze or cough. Masks prevent one's droplets from spreading out.
There was and still is a lot of cultural resistance in 'western' societies to wearing masks even as it seem obvious that masks help to prevent infections. But while there was evidence that masks work in certain situation there was no scientific research that showed the effects general mask wearing would have on the growth of the epidemic. We did not know how much general mask wearing would 'flatten the curve'.
We now have a sound answer. There is now a study that compares a city which ordered everyone to wear masks with a similar city that had no 'mask-up' order during the same period of the epidemic.
On April 6 the German city of Jena with a population of 110,000 people ordered everyone to wear a mask in all public settings. The announcement of the order was made a week earlier and was followed by a local awareness campaign – "Jena wears mask!"
No other city in Germany did this at the time. The states of Germany only ordered mandatory mask wearing between April 22 and 26.
For 20 days Jena was different than the rest of the country but experienced the same epidemic. That made it possible to test the effect the mask order had on the number of new cases in Jena.
To be able to make a one to one comparison with Jena researchers from the University of Mainz constructed a 'synthetic city' of the same size and demographic characteristics as Jena from the weighted data of six other German cities (selected from a bigger pool). They then compared the Covid-19 case data from Jena with the case data from the synthetic city.
At the beginning of the pandemic in Germany the synthetic city and Jena had similar developments. But ten days after the announcement of the order and four days after its mandatory implementation the case numbers in Jena dropped away from those of the comparison city.
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The people in Jena started to wear masks before other German cities did so. It nearly immediately paid off.
At the time of the announcement of the mask campaign Jena and the synthetic control city each had 93 cases. On April 6 Jena had 142 registered cases compared to 143 cases in the synthetic control city. On April 26 Jena counted 158 cases and the synthetic control city had 205 cases. It shows a significant reduction in the growth of the epidemic.
The authors conclude:
We believe that the reduction in the growth rates of infections by 40% to 60% is our best estimate of the effects of face masks.
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We should also stress that 40 to 60% might still be a lower bound. The daily growth rates in the number of infections when face masks were introduced was around 2 to 3%. These are very low growth rates compared to the early days of the epidemic in Germany, where daily growth rates also lay above 50%. One might therefore conjecture that the effects might have been even greater if masks had been introduced earlier.
Japan and South Korea both brought the epidemic under control without ordering harsh lockdowns. The people there all wore masks from very early on even without being ordered to do so. The two countries also did extensive testing and contact tracing for each new case. Together these measures were enough to stop the outbreak.
Why didn't we copy them?
It was 'western' arrogance that prevented our societies from learning from China and other Asian societies. We should have used the time China had given us. The economic and human price for not having done so is very high.
