Watch movies at home. Skip concerts. Don't meet with colleagues for a coffee or after-work drink. The COVID pandemic has been posing a threat to many in Germany for one and a half years now, forcing people to change the way they lead their lives.

That, at least, is the conclusion drawn by "Contact Monitor" — a research group led by Professor Dirk Brockmann at Berlin's Humboldt University. Brockmann calls himself a complexity researcher and he and his team advise the Robert Koch Institute (RKI), Germany's independent government agency responsible for monitoring and combating infectious diseases.

Brockmann and his team have collated and assessed anonymous GPS data from more than a million mobile phones across Germany. The aim: to identify moments when two mobile devices met for at least two minutes at the same location, which then counted as a "contact." Before the pandemic, each cellphone user had an average of 20 such contacts each day.

Caution prevails

"The figure is now back at about half that level," Brockmann tells DW. "It is very likely due to the fact that we're still not eating in restaurants as regularly as we used to and that we avoid all sorts of different kinds of events where there's a lot of contact."

The frequency of contact is moving back up towards normal levels, but only very slowly, says Brockmann: "Much more slowly than contacts were reduced during the first wave of COVID."

Within two weeks in March 2020, the average number of contacts fell rapidly. The German parliament imposed "a national epidemic state of emergency" on March 25, 2020, by which time the average number of contacts across the country had already fallen to fewer than nine a day.

"Although it was not the biggest wave, people reacted very quickly, very intensively. There was suddenly an unknown pandemic at their door: an unknown virus," says Brockmann, adding that people's personal perception of the menace they faced played a big role. "A much bigger role than, for instance, the political measures that were taken — the lockdown."

"All measures discontinued"

Those political measures now look likely to gradually expire. Three political parties — the center-left Social Democrats (SPD), Greens and neoliberal Free Democrats (FDP) — are negotiating to form Germany's next government. At the start of their talks on Wednesday they announced their willingness to let the national pandemic state of emergency expire on November 25. Social Democrat, Dirk Wiese, put it like this: "With the new government, there will be no more school closures, lockdowns or curfews. In the current situation," he added, "they are simply not proportional solutions."

However, Germany's regional authorities will continue to be permitted to enforce measures like social distancing and the wearing of masks until the spring of next year. But: "All measures will be discontinued by the beginning of spring on March 20, 2022, at the latest," said ranking Free Democrat Marco Buschmann.

People get lazy

Regardless of political measures, people's individual behavior, in part at least, depends on their personal assessment of risk factors. When the numbers fall, people tend to be more ready to seek contact.

"But when infection levels go through the roof, as is currently the case, then people will adopt a more vigilant approach out of concern that they might be infected," says Brockmann. He describes it as a "proportional interaction between the numbers and how people behave."

However, this interaction has slowed down in the 18 months of the pandemic. "People are getting lazy in their ways. Society becomes less vigilant as people get used to the situation," he says.

Brockmann points to the threat posed by the highly infectious delta variant of coronavirus and warms people not to become complacent where social distancing and the wearing of masks are concerned. Which, he is quick to add, also applies to those who are fully vaccinated. They might be protected from serious illness: "But the probability of being infected is not reduced by 100%. There is still a residual risk of being infected and not noticing it."

Brockmann and his colleagues have also begun to use data from fitness trackers — provided voluntarily by users — in order to build their models. This enables the researchers to detect how many people throughout Germany develop a fever — which also helps to estimate the number who might be infected with the virus. These research efforts are currently being expanded, with users becoming so-called data doners.   

Smartphone data donation

Using their smartphones, more than half a million people have had the opportunity to become data donors and take part in surveys probing the psychological aspects of the pandemic. Complexity researcher Brockmann is now cooperating with psychology professor Cornelia Betsch.   

Unlike in the US, such interdisciplinary projects are not easy to get off the ground in Germany. But Brockmann says the new approach is crucial: "The pandemic is in itself primarily a psychological phenomenon" that affects interpersonal relationships and person-to-person contact. Compared to other EU countries, Germany has a high number of people reluctant to get vaccinated — this too is something for psychologists to research.

The scientists hope that their work will help the country's political leaders to avoid repeating some of the mistakes made during the last year and a half. Nevertheless, the fact remains that it is the politicians themselves who have to make the tough calls.

Brockmann at the Humboldt University in Berlin has a personal mantra, which he is happy to share with Germany's new government: "In the pandemic, communication is the key."

This article has been translated from German.

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