How face masks have helped slow down the spread of coronavirus in Germany

Face masks became mandatory in Germany at the end of April, but how effective are they? A new study highlighting the eastern city of Jena sheds some light on the controversial measure.

How face masks have helped slow down the spread of coronavirus in Germany
A person wearing a face mask in Jena on April 6th. Photo: DPA

They have become synonymous with the coronavirus outbreak: whenever you’re travelling on a bus, train or shopping in a supermarket in Germany, you’ll find most people are wearing a covering over their mouth and nose.

But the introduction of face masks has been controversial, not only in Germany but across the world, with conflicting advice from experts particularly at the beginning of the pandemic.

Now a study by German researchers, which has gained international attention, has found mandatory face masks reduce the daily growth of reported coronavirus infections by around 40 percent.

And one German city was way ahead of the curve: the Thuringian university town of Jena, led the way by introducing a mask obligation (Maskenpflicht in German) on April 6th while other states across the country were hesitating.

Timo Mitze, Associate Professor at the University of Southern Denmark who is one of the authors study that hones on in how face Masks reduce Covid-19 in Germany, told The Local that Jena was a “pioneer”.

By the end of April, all German states brought in a rule saying people had to wear masks while travelling on public transport and in shops, some weeks after Jena.

READ ALSO: Jena becomes first German city to make wearing a face mask mandatory

Masks had 'positive effect' in Jena

So how effective has the mask obligation been in Jena?

“If we look at the number of Covid-19 cases in Jena, masks seem to have a positive effect,” Mitze said in an evaluation of the study.

“The number of registered new infections fell to almost zero in the days after masks were introduced. But was this really due to the introduction of masks and a publicly visible campaign?”

Researchers came up against limitations.

“Unfortunately, there is no second Jena in Germany, which would allow us to measure the spread of Covid-19 if face masks had not been introduced under otherwise identical conditions,” said Mitze.

The authors instead used a synthetic control method to compare Jena to similar regions in Germany (such as Rostock, Darmstadt, and Trier) that did not introduce the mask obligation until later. 

According to their calculations, “there is a significant gap between the number of cases in Jena and the comparison group without compulsory masks”. 

Twenty days after the introduction of compulsory masks in Jena, the total number of Covid-19 cases registered there had only risen from 142 to 158, whereas in the comparison model it had risen from 143 to 205. This corresponds to a reduction in the number of cases in Jena by around 23 percent.

The drop in Jena was greatest – more than 50 percent – for the age group of 60 and above, indicating that masks are useful for risk groups.

Face masks on statues in Jena. Photo: DPA

In a second set-up, the researchers investigated the development of the number of cases in the cities and districts that introduced compulsory masks before or on April 22nd, including Nordhausen in Thuringia, Rottweil in Baden-Württemberg, the Main-Kinzig district in Hesse, and Wolfsburg in Lower Saxony. 

The study authors – Mitze, Reinhold Kosfeld, Johannes Rode and Klaus Wälde – compared these regions with those that introduced masks on April 27th or later. 

They found smaller effects than in the Jena case study. However the average reduction in case numbers “remains significant and sizeable”, say the authors.

A total of 10 days after the introduction of masks, the decrease in the cumulative cases is between 2.3 and 4.2 percent.

Mitze said that taking all of the research into account, the daily growth rate of Covid-19 cases in Germany dropped by about 40 percent. 

“The introduction of mandatory face masks has slowed down the spread of Covid-19 in Germany,” he said. “This result agrees with the findings of epidemiologists and virologists who explain that face coverings limit airflow when speaking, thereby reducing the transmission of infectious particles.”

READ ALSO: Why a row has broken out in Germany over face masks

So why were masks so successful in Jena?

Mitze told The Local it could be down to more than one factor, such as the social aspect – not only the medical effect of wearing a face covering.

“There is the medical effect when you wear the mask – the transmission channels are blocked to a certain extent,” said Mitze. “Then on top of that there is this social aspect of being cautious (when there is a mask obligation in place).”

Mitze said Jena’s campaign “Jena zeigt Maske” (Jena shows mask), which was put in place a week before the introduction of the rule, may have helped locals become familiar with the restriction. 

“Jena is a pioneer city,” said Mitze. “So maybe the response to face masks there was particularly strong.”

This could all have contributed to people in Jena behaving much more cautiously (for example observing hygiene and distance regulations), while taking the measure seriously and sticking to the rules.

Should masks remain in Germany even when Covid infection numbers drop?

A debate was sparked in Germany this week over whether the mask obligation should be partially scrapped to support businesses.

Mecklenburg-Western Pomerania economy minister Harry Glawe spoke out in favour of getting rid of the mask requirement to help the pandemic-hit retail trade. However, states decided to keep the rule in place.

READ ALSO: Face masks to remain mandatory in shops across Germany

According to Mitze, the results of the study suggest that Germany’s face mask requirement is a “cost effective, less economically harmful, and democracy-compatible containment measure for Covid-19”, especially compared to other measures such as closing schools, shopping centres and restaurants. 

However, he understands why the retail sector, for example, would be keen to get rid of the mask requirement. 

Mitze said: “My opinion is: comparing it to the risk of another lockdown with limiting personal freedoms of moving around and closing down the economy, then – relatively – the costs of wearing face masks are low.”

Tobias Kurth, professor of public health and epidemiology at the Charité in Berlin, said wearing a face mask “helps to reduce the likelihood of coronavirus spread”.

“This is also true for Germany,” he added. “It is key that we keep on wearing face masks in public transportation or public indoor places and yes, this should be mandatory.

“This is small but effective way to help to control the pandemic. We should keep on doing this until there are other effective ways to control the pandemic, such as a vaccination that is effective and available.”

'Relatively mild remedy'

Politicians, scientists and researchers have also warned against removing the requirement too quickly, just as people have got used to them.

Mitze said people were very wary of wearing masks initially “but now people seem to have adjusted to this”.

“If you relax a measure, how easy can you reintroduce it back again?” he said. However, he acknowledged for some groups, such as people with difficulties hearing, face masks can be trickier.

A man wearing a mask in Berlin. Photo: DPA

Mitze said innovations, such as transparent face masks and other new ways of covering the face, could help break down these barriers.

These comments mirror Federal Health Minister Jens Spahn who on Thursday warned against relaxing the mask requirement too early.

READ ALSO: 'They're warm and you can't breathe well': Germans don face masks for first time

In order to reduce the risk, there is an obligation to wear masks in certain public settings, said the Christian Democrat (CDU) politician. In his view, he said: “It's better to have it (the restriction) lifted three weeks too late than three weeks too early”.

He said that wearing masks was not always pleasant, but that it was a “relatively mild remedy” compared to other restrictions. This is particularly important when distances cannot be maintained, such as on public transport or when shopping, Spahn said.

While there is no vaccine or treatment and the risk of second wave remains very real, evidence suggests masks are a useful tool.

“What is the alternative?” said Mitze. “Opening the economy now and risking a much steeper second wave? Second round costs may even be much higher if one relaxes face masks too early.”

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FACT CHECK: Did Sweden have lower pandemic mortality than Denmark and Norway?

A graphic published by the Svenska Dagbladet newspaper last week claimed that Sweden had the lowest excess mortality of all EU and Nordic counties between the start of 2020 and the end of 2022. We looked into whether this extraordinary claim is true.

FACT CHECK: Did Sweden have lower pandemic mortality than Denmark and Norway?

At one point in May 2020, Sweden had the highest Covid-19 death rate in the world, spurring newspapers like the New York Times and Time Magazine to present the country as a cautionary tale, a warning of how much more Covid-19 could ravage populations if strict enough measures were not applied. 

“Per million people, Sweden has suffered 40 percent more deaths than the United States, 12 times more than Norway, seven times more than Finland and six times more than Denmark,” the New York Times reported in July 2020

An article in Time in October 2020 declared Sweden’s Covid response “a disaster”, citing figures from Johns Hopkins University ranking Sweden’s per capita death rate as the 12th highest in the world.

So there was undisguised glee among lockdown sceptics when Svenska Dagbladet published its data last week showing that in the pandemic years 2020, 2021 and 2022 Sweden’s excess mortality was the lowest, not only in the European Union, but of all the Nordic countries, beating even global Covid-19 success stories, such as Norway, Denmark and Finland. 

Versions of the graph or links to the story were tweeted out by international anti-lockdown figures such as Bjørn Lomborg, a Danish sceptic of climate action, and Fraser Nelson, editor of Britain’s Spectator Magazine, while in Sweden columnists like Dagens Nyheter’s Alex Schulman and Svenska Dagbladet’s opinion editor Peter Wennblad showed that Anders Tegnell, the state epidemiologist who led Sweden’s strategy had been “right all along”. 

Excess mortality — the number of people who die in a year compared to the number expected to die based on previous years — is seen by some statisticians as a better measure for comparing countries’ Covid-19 responses, as it is less vulnerable to differences in how Covid-19 deaths are reported. 

But are these figures legitimate, where do they come from, and do they show what they purport to show?

Here are the numbers used by SvD in its chart: 

Where do the numbers come from? 

Örjan Hemström, a statistician specialising in births and deaths at Sweden’s state statistics agency Statistics Sweden (SCB), put together the figures at the request of Svenska Dagbladet. 

He told The Local that the numbers published in the newspaper came from him and had not been doctored in any way by the journalists.

He did, however, point out that he had produced an alternative set of figures for the Nordic countries, which the newspaper chose not to use, in which Sweden had exactly the same excess mortality as Denmark and Norway. 

“I think they also could have published the computation I did for the Nordic countries of what was expected from the population predictions,” he said of the way SvD had used his numbers. “It takes into consideration trends in mortality by age and sex. The excess deaths were more similar for Denmark, Sweden, and Norway. Almost the same.” 

Here are Hemström’s alternative numbers: 

Another issue with the analysis is that the SvD graph compares deaths in the pandemic years to deaths over just three years, a mean of 2017-2019, and does not properly take into account Sweden’s longstanding declining mortality trend, or the gently rising mortality trend in some other countries where mortality is creeping upwards due to an ageing population, such as Finland. 

“It’s very difficult to compare countries and the longer the pandemic goes on for the harder it is, because you need a proper baseline, and that baseline depends on what happened before,” Karin Modig, an epidemiologist at Sweden’s Karolinska Institute whose research focuses on ageing populations, told The Local.

“As soon as you compare between countries, it’s more difficult because countries have different trends of mortality, they have different age structures, and in the pandemic they might have had different seasonal variations.” 

She described analyses such as Hemström’s as “quite crude”. 

In an interview with SvD to accompany the graph, Tegnell also pushed back against giving the numbers too much weight. 

“Mortality doesn’t tell the whole story about what effect a pandemic has had on different countries,” he said. “The excess mortality measure has its weaknesses and depends a lot on the demographic structures of countries, but anyway, when it comes to that measure, it looks like Sweden managed to do quite well.”

Do the numbers match those provided by other international experts and media? 

Sweden’s excess mortality over the three years of the pandemic is certainly below average worldwide, but it is only in the SvD/SCB figures that it beats Norway and Denmark. 

A ranking of excess mortality put together by Our World in Data for the same period as the SvD/SCB table estimates Sweden’s excess mortality between the start of 2020 and the end of 2022 at 5.62 percent, considerably more than the 4.4 percent SvD claims and above that of Norway on 5.08 percent and Denmark on 2.52 percent. 

The Economist newspaper also put together an estimate, using their own method based on projected deaths.  

Our World in Data uses the estimate produced by Ariel Karlinsky and Dmitry Kobak, who manage the World Mortality Dataset (WMD). To produce the estimate, they fit a regression model for each region using historical deaths data from 2015–2019, so a time period of five years rather than the three used by SCB.

What’s clear, is that, whatever method you use, Sweden is, along with the other Nordic countries, among the countries with the lowest excess mortality over the pandemic. 

“Most methods seem to put Sweden and the other Nordic countries among the countries in Europe with the lowest cumulative excess deaths for 2020-2022,” said Preben Aavitsland, the Director for Surveillance and the Norwegian Institute of Public Health.

So if Sweden had similar excess mortality as the other Nordics over the period, does that mean it had a similar Covid-19 death rate?

Not at all. Sweden’s per capita death rate from Covid-19 over the period covered by the SvD/SCB figures, at 2,249 per million people, is more than double Norway’s 959 per million, 60 percent more than the 1,409 per million who died in Denmark, and more than 50 percent more than the 1,612 per million who died in Finland. 

While Sweden’s death rate is still far ahead of those of its Nordic neighbours, it is now much closer to theirs than it was at the end of 2020. 

“The most striking difference between Sweden and the other Nordic countries is that only Sweden had large excess mortality in 2020 and the winter of 2020-21,” Aavitsland explained. “In 2022, the field levelled out as the other countries also had excess mortality when most of the population was infected by the omicron variant after all measures had been lifted.”

So why, if the Covid-19 death rates are still so different, are the excess mortality rates so similar?

This largely reflects the fact that many of those who died in Sweden in the first year of the pandemic were elderly people in care homes who would have died anyway by the end of 2022. 

About 90 percent of Covid-19 deaths were in people above 70, Aavitsland pointed out, adding that this is the same age group where you find around 80 percent of all deaths, regardless of cause, in a Scandinavian country.

“My interpretation is that in the first year of the pandemic, say March 2020 – February 2021, Sweden had several thousand excess deaths among the elderly, including nursing home residents,” he said. “Most of this was caused by Covid-19. In the other [Nordic] countries, more people like these survived, but they died in 2022. The other countries managed to delay some deaths, but now, three years after, we end up at around the same place.” 

So does that mean Sweden’s state epidemiologist Anders Tegnell was right all along? 

It depends on how you view the shortened lives of the close to ten thousand elderly people who caught Covid-19 and died in Sweden in the first wave because Sweden did not follow the example of Denmark, Norway, and Finland and bring in a short three-week lockdown in March and April 2020. 

Tegnell himself probably said it best in the SvD interview. 

“You’ve got to remember that a lot of people died in the pandemic, which is of course terrible in many ways, not least for their many loved ones who were affected, so you need to be a bit humble when presented with these kinds of figures.”