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Photo: UMC Utrecht
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Massive and repeated testing of the population for the coronavirus, followed by isolation of those who can spread the virus, after the current wave is not feasible as a solution to reopening society. This conclusion is drawn in a new modeling study by epidemiologists from UMC Utrecht and Utrecht University.
To limit the social and economic costs of the lockdown measures, a strategy is needed that controls the spread of the coronavirus and at the same time makes it possible to eliminate these measures. Regular mass screening of large parts of the population, regardless of whether there are corona complaints, has recently been proposed as a possible control strategy whereby society can (largely) be reopened again. According to this proposal, from March 2021 onwards, every Dutch person could be tested on average once a month, even if there are no symptoms. To achieve that goal, the Ministry of Health, Welfare and Sport wants to increase the capacity to 10 million tests per month. However, it is not known whether such a strategy can actually control the spread of the virus.
Research leader Marc Bonten (UMC Utrecht) interprets the results of the modeling study as follows: “Regular mass screening, followed by isolation of infectious persons does not seem a realistic strategy to fully reopen society after the current corona wave. More targeted screening will therefore be necessary to be able to use these rapid tests in a meaningful way as a supplement to other control measures. For example, we can think of mass screening in parts of the country where the contamination level is high or in population groups where there is a lot of spread. ”
Assuming a natural R0 of 2.5 (this means that without measures, each coronavirus infected will infect an average of 2.5 people), the study shows that the complete overriding of controls for tested subjects with a negative test result requires that the full population should have a rapid test more often than every three days to keep the reproduction number below 1. If the social distancing measures are maintained (the situation in the Netherlands in August 2020), 60 percent of the population would still have to have themselves tested every week to prevent the spread of the corona virus from getting out of hand.
Researchers from the Epidemiology of Infectious Diseases Department of UMC Utrecht and Utrecht University have developed a mathematical model to investigate whether mass testing of the population, including people without complaints, can stop the spread of the coronavirus. The idea behind this is that massive and regular screening can also identify and isolate asymptomatic spreaders of the virus. In developing their model, the researchers used variables such as reproduction number (R0), test sensitivity, test frequency, virus spread after a false negative test, virus spread by individuals who do not undergo testing, the effectiveness of self-isolation after a positive test. and the proportion of the population that is tested. They then calculated the required test interval and coverage to keep the reproduction number below 1 in mass and repeated testing.
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