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The number of cases has increased because the cantons could no longer trace the contacts of those infected. The scientific working group is now making suggestions that tracking can be made more efficient.
Marcel Salathé recommends that an app warn visitors of events if a person infected with corona was present.
During the first Corona wave, it only took a few days for the cantons to become overwhelmed with contact tracing across the board. In the first half of October, contact tracing and identifying potential contagion clusters stopped working for long periods. Canton by canton had to close contact tracing in view of the sharp increase in the number of cases. Warnings about infected people and their contacts were delayed or did not materialize.
Lessons from failure
The working group recently published a new report with lessons from the second wave and strongly recommends improving the scalability of manual contact tracing. The task force believes that the Test, Trace, Isolate and Quarantine (Triq) strategy should receive financial support from the federal government as an integral part of the Covid-19 strategy.
“As has already been done with testing, the federal government can create clarity by making funds available for contact tracing,” says Marcel Salathé, epidemiologist and member of the Covid-19 scientific working group. This would go a long way towards making cantonal measures quickly more efficient and scalable. “The federal government has taken note of the proposals made by the Scientific Working Group and will review them in the coming weeks,” writes the Federal Office of Public Health at the request of NZZ.
“We keep flying in the dark,” Salathé explains. “Due to the lack of data, it is difficult to say when and why the collapse occurred at the cantonal and federal level.” That must urgently change, as the Triq strategy is the most important containment measure whenever a vaccine is not available in sufficient quantities.
Contact follow-up procedures need to be simplified and optimized. Infected people and their contacts should be reached as soon as possible so that they can take steps such as isolation and quarantine.
Salathé suspects that the situation in the cantons is very different in this regard. It is true that software solutions are being used more and more, but it is difficult to judge the success of these approaches due to the lack of indicators. “If they follow different approaches in the cantons, they can quickly learn from each other,” emphasizes Salathé. This is precisely why indicators are so important.
The working group recommends establishing systematic inter-cantonal communication. Canton doctors would have to coordinate with each other. This is very important because many index patients (infected people) crossed cantonal borders during their period of infection.
Track Superspreader
In its policy brief, the advisory committee places great emphasis on tracking down sources of infection, known as clusters. It has now been scientifically proven that higher than average number of infections occur in super-propagation events. “That is why it would be important that the contact trackers in use detect such groups, that they are used for tracking,” explains Salathé.
According to the working group’s plans, the SwissCovid app could also play an important role. She suggests adding a national time and attendance solution to the app. Specifically, this would be solved in such a way that the organizers emit a QR code that is scanned by as many visitors as possible. If this time there were cases of Covid-19 infection, all users of the application would be automatically informed.
According to Salathé, data protection principles such as data minimization, purpose limitation and decentralization of data storage must be observed. The same standards as with the old application should also be applied to the new applications.
Mathias Wellig, director of Ubique, the company that developed the SwissCovid app, thinks this idea makes perfect sense. “Together with Carmela Troncoso’s group at the Swiss Federal Institute of Technology in Lausanne (EPFL), we seek a scalable approach while protecting privacy.” The first steps towards implementation in practice have already been taken. For example, EPFL has introduced a protocol called CrowdNotifier. “Based on this, we developed the NotifyMe application, which shows what such a solution can look like,” Wellig explains when asked by the NZZ. The application should be available for download in the Apple and Android stores in the second half of November.
New app before launch
The crowd notifier approach offers the ability to specifically notify people who are present at an event or venue with a single click. According to the head of Ubique, this has the decisive advantage that this process can be scaled: you only have to make one click to potentially notify a large number of people. Time-consuming individual contact is no longer necessary. Furthermore, this system can be implemented in such a way that a central storage of users’ personal data is not necessary.
This functionality can be implemented in a standalone application such as NotifyMe or by expanding the SwissCovid application. Integrating such a system into SwissCovid would lead to additional benefits. “One could imagine that people who tested positive and authenticated with their impersonal Covid-19 code can optionally send records to authorities during their infectious period,” Wellig emphasizes. If a sufficient number of people did this, it would be possible to identify clusters very early by observing that there are several reports for the same place at the same time.
