Viennese researchers say herd immunity is not a suitable strategy for Austria – Coronavirus Vienna

Viennese demographers present in the magazine “PLOS One” a new method to estimate the number of people infected with the SARS-CoV-2 virus in a country.

His bills showed that even in critical hotspots in the crown, like the US states of New York and New Jersey, probably only less than 20 percent of the population was infected. This is still a long way from herd immunity. In Austria, researchers arrive at an infection rate of around seven percent.

The indirect estimation method of the team of scientists from the Institute of Demography of the Austrian Academy of Sciences (ÖAW) and the Technical University (TU) of Vienna takes into account the age structure of the population, the general mortality rate in relation With age, those associated with Covid-19 deaths and Covid-19 deaths relative to the documented number of infected people (mortality cases). Using mathematical models, the researchers also estimated how many of the actual cases were detected through testing, according to a broadcast from the Austrian Academy of Sciences on Wednesday.

Analyzes by Miguel Sánchez-Romero and Vanessa Di Lego and their colleagues showed that in most countries, only about 60 percent of cases were detected using the above testing strategies. This value also applies to Austria, as Sánchez-Romero explained at the request of the APA. “Different testing procedures, asymptomatic people and the limited availability of large-scale tests reduce the chances of actually detecting all cases,” says the first author of the work.

The scientists also obtained information on the number of unreported cases using a statistical procedure. “With our model, we can estimate how many people have ever been infected with Covid-19 for any population,” Di Lego said. In their work, the team focused on the US, the country that has so far recorded the highest death toll from Covid 19. Even for the states of New York and New Jersey, with contamination estimated at 20 percent. Herd immunity, for which, according to experts, about 60 percent of the population would have to be protected, is still a long way off.

“Our method shows that herd immunity is not an appropriate strategy here,” Di Lego said. This applies even more to Austria, “where we are still far from a level that stops the spread of the virus,” Sánchez-Romero said.

The team notes that their estimates for several countries are in very good agreement with the results of seroprevalence studies in which the number of people already infected is sampled based on the presence of antibodies in the blood and then extrapolated to the total population. Such exams are time consuming and expensive. Therefore, scientists see their method as a complementary option.

“Our model is a suitable tool for use around the world, without having to know all the specific details of each country,” says Sánchez-Romero, who also sees the approach as a tool to verify if the vaccine strategy is working. and to what extent vaccines are actually working to prevent deaths. “