pandemic control
Corona tests only for certain groups? This is what the optimal test strategy could look like
Vaccinated or recovered? That doesn’t matter anymore, because 2G-Plus applies in many areas. That means tests for everyone who wants to take part in public life.
© Hauke-Christian Dittrich / DPA
Corona tests have been part of the arsenal of weapons used to combat the virus since the beginning of the pandemic. They are mainly used to keep an eye on the infection process. But the right strategy has always been the subject of arguments.
In Austria, an initial euphoria is now giving way to disillusionment and helplessness. The country had recently driven an unprecedented test strategy. Above all, the provincial capital of Vienna attracted positive attention with its comprehensive range of offers in Germany. The motto was free PCR tests for everyone. The Germans, whose high-quality tests had just been cut, glared enviously at the Alpine Republic. In Vienna, the land of plenty, there were PCR tests on every corner – and the samples could be returned directly there. Thanks to the pooling process used across the board, every citizen could test themselves at any time.
But now there are doubts. The incidence had risen continuously since the beginning of the year, and the country has currently recorded almost 2,600 new infections per 100,000 inhabitants within the last seven days. It doesn’t seem like Austria has the pandemic better under control just because more testing is being done.
For epidemiologists it is now clear: “Aimless criss-cross testing by the entire population (has) only a very small epidemiological influence on the overall situation”. The problem: Contact tracing collapsed under the numerous test results, and there are no longer any consequences for those who tested positive and for contact persons. “It needs a strategy on who we want to focus the tests on,” pleads, among other things, epidemiologist Gerald Gartlehner from the Danube University in Krems in the “Standard”.
Could Germany become a role model?
In Germany, too, experts have long been in agreement: Testing the population without cause and aim is of little use. Two weeks ago, the laboratories warned of an overload due to too many PCR samples. And the rush is still enormous. As reported by the Association of Accredited Laboratories (ALM), 2,477,154 PCR tests have been carried out in all 182 specialist laboratories since January 31st. The positive rate rose to 45 percent. “In many federal states, more than half of all samples evaluated are already positive,” says the press release.
According to the recently adjusted national test strategy, risk groups should be prioritized for PCR tests in the future. The rapid antigen tests are therefore intended for all others. A spokesman for the laboratory network Bioscientia told the starthat this would potentially identify fewer positive cases. For example, there is a risk that travelers or people in quarantine will falsely test themselves free because the viral load is too low for the antigen tests – but this does not mean that the people are no longer contagious. However, not prioritizing would mean endangering the healthcare system and vulnerable groups.
The ALM said that they welcomed the “implementation of a meaningful prioritization based on medical principles”. One cannot test oneself out of the pandemic. “The benefit of unprovoked mass testing with too low a participation rate by the population has not yet been scientifically proven.”
Prefer to dose tests?
A research group led by Petra Dickmann, which is researching global pandemic and outbreak management at the University Hospital in Jena, developed a concept for strategic testing in the summer of 2020. In order to introduce possible nationwide health measures, it is important to also observe the role of schools. “It was not about individual medicine and the question of whether Marie and Jonas are positive, but how many infections occur in schools (and daycare centers) and what measures are best used to contain them,” she said star.
Tatü Tata, the corona test is here
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The research group relied on pooled testing. Several test samples are analyzed together. If the result is positive, the samples are examined individually again. Dickmann sees this as “a sensible, resource-saving measure”. This could also be used to draw conclusions about developments in the overall population. In times of low incidence, the expert recommends testing in specific groups using the pooling method. However, it is difficult to say how low the incidence must be. “If the goal is to detect and interrupt infections or particularly predisposed infection sites at an early stage, comprehensive strategic testing is good.” If the goal were to prevent severe disease progression, it would make more sense to give preference to medical facilities and vulnerable groups and to protect them. In this way, limited resources can also be saved.
In so-called low-risk areas, such as schools, where there are no serious illnesses, the tests are a hindrance because they interrupt school operations. Overall, the researcher is in favor of pooled testing in specific areas. “I would also like to have scientific support so that we finally get more evidence about how the infection process develops,” she said star.
However, Dickmann emphasizes: “The best protection against a serious illness is vaccination – a test always only gives a snapshot with varying validity.”
Sources:“The standard”, Association of Accredited Laboratories