According to data from the Robert Koch Institute, 195,674 people in Germany have been shown to have been infected with Sars-CoV-2 since the outbreak of the corona pandemic (as of July 3, 2020). However, experts assume that the number of unreported cases is high, because not every infection is discovered. In particular, the symptom-free and mild course of the disease, which is often mistaken for a cold, is largely not recorded in the RKI statistics. However, the infected develop antibodies. A corresponding test can provide information about this.
Helmholtz Center starts nationwide antibody study
Numerous studies are being carried out in Germany to find out how many people have actually come into contact with Covid-19. The largest and only nationwide survey by the Helmholtz Center for Infection Research (HZI) starts today. “We want to better understand the speed at which the corona virus spreads, which population groups are affected and how many are likely to be immune,” study leader Gérard Krause told the German Press Agency.
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A total of approximately 60,000 blood samples are to be examined in the study. The Baden-Württemberg district of Reutlingen will start, followed by ten more municipalities. In order to measure the course of the pandemic, a second survey phase should be carried out in all test areas after a few months. According to the scientists, the percentage of people actually infected in the population is valuable information for dealing with the pandemic.
Heinsberg and Kupferzell: studies on corona hotspots
But there are other antibody studies that deal with the spread of Sars-CoV-2 in the population. The Robert Koch Institute provides an overview of these so-called seroepidemiological studies. According to this, at least 24 surveys are currently being carried out, in which either the general population is tested for Covid-19 antibodies or selected population groups.
The Federal Institute has been introducing itself since May Corona-Monitoring in particularly affected places. On the basis of data from local hotspots such as Kupferzell or Bad Feilnbach, the infectologists want to use existing antibodies to demonstrate how high the proportion of infections that are without symptoms of illness and which people are particularly affected by Covid-19.
Even the controversial Heinsberg study by the Bonn virologist Hendrik Streeck is such a hotspot survey. For the study, 21 quarantine households in Gangelt in the Heinsberg district were examined, where the coronavirus had spread rapidly after a carnival event. 26 out of 43 adults tested positive for Covid-19, but 22 percent of the participants showed no symptoms. “What we see is that people with asymptomatic courses also develop immunity or partial immunity,” Streeck explained the test results. For this reason, he also had the hope that, with the increasing easing over the summer, a creeping immunity could build up in the population.
UKE researches corona courses in children and the elderly
Possible corona risk groups are also the focus of further studies. For example, the University Clinic Eppendorf (UKE) has been investigating the spread of the virus in older people and children since the end of April. Accompanying the Hamburg City Health Study launched in 2016, 6000 people aged 45–74 years are now to be examined for antibodies that have formed. The doctors are particularly interested in finding out about the so-called infection and immunity of the Hamburg population.
The first results on how often children get Covid-19 are already available. Only 36 of the 2436 children tested were able to detect antibodies against Sars-CoV-2 in the blood. “Initial evaluations show that only 1.5 percent of children and adolescents have produced antibodies and that we are far from herd immunity,” said Prof. Dr. Ania Muntau, director of child and adolescent medicine at the UKE, recently at a press conference. It is also striking that mostly older children were affected. The younger the children, the fewer antibodies there would be, said Mantau.
How does the corona virus spread in schools?
The opening of schools and the return to normal school operations is nevertheless associated with a certain degree of uncertainty. In order to get an accurate picture of the current infection status with Sars-CoV-2 and its development at Saxon schools, Leipzig doctors started a wide-ranging study at the end of May. A total of 2000 students and 1000 teachers are to be tested for antibodies.
“As only symptom-free children and teachers are tested here, this study not only fulfills an important function in the context of infection protection in Saxon schools, but also creates clarity with regard to the controversial actual frequency of symptom-free infections, especially in children,” says study leader Prof. Wieland Kiess in a message from University of Leipzig. At the beginning of the new school year and in autumn, further surveys are planned to monitor the development of the infection process.
Whether children one Infection risk for their parents or grandparents the University of Rostock examined. In April they tested 401 Rostock mothers for the pathogen and for antibodies. The scientists were unable to detect any Covid 19 viruses in any of the throat swabs. All mothers were also negative in the antibody test. The doctors conclude from this that, although no mother had contact with the coronavirus, the school and daycare closures would still have slowed the spread of the infection.
Possible risk group: Studies examine contagion of pregnant women and babies
In addition to older and previously ill people, pregnant women are also at risk for Covid-19 because the volume of lungs decreases during pregnancy. The University Women’s Clinic in Erlangen therefore examined 2,400 pregnant women over a period of three months.
The study aims to determine how many of the women are or have been infected with the coronavirus and whether the infection causes complications during pregnancy or childbirth. The doctors also want to clarify the question of whether infected mothers can transmit the virus to the child. So far, this possibility has been assessed as low.
Contact with infected people: How endangered is medical clinic staff?
Medical studies that have contact with corona patients in clinics have also been the subject of several studies. Scientist of the Hannover Medical School (MHH) are currently investigating how often healthcare workers are infected with Sars-CoV-2. A total of 1,000 nurses and doctors are participating in the study. 200 of them are even examined weekly.
Initial results showed that antibodies to the coronavirus were present in less than one percent of the first 180 employees tested. “We hope that the number of asymptomatic infections in the next few weeks and months will be particularly valuable,” says study leader Professor Dr. Behrens. The antibody tests should also provide information about when there is an immune reaction after contact with Covid-19 and when appropriate protection is built up. But these are also prone to errors. Therefore, the quality of rapid tests should also be checked with the blood samples obtained as part of the MHH study.