92 percent of adults in Germany had been vaccinated against Sars-CoV-2 by the turn of the year 2021/2022 or had been infected with the pathogen at least once in the previous months. This number is one of the results of the study “Corona Monitoring nationwide – Wave 2” by the Robert Koch Institute (RKI) together with the Socio-Economic Panel (SOEP) at the German Institute for Economic Research (DIW). Among 14- to 17-year-olds, the estimated “seroprevalence” was 86 percent. No significant differences were found between women and men.
Between November 2021 and February 2022, 11,162 volunteers from 6,760 households took part in the study, more than 20,000 had been requested. The test persons took a small blood sample from their fingertip, which was sent in. They also answered a questionnaire about vaccinations and possible infections, which were confirmed by a PCR test. The blood samples were finally examined in the laboratory for antibodies against the corona virus. The test used was not able to distinguish between antibodies that the body had formed after a vaccination and those that are released as a result of an infection. “The desired distinction between vaccinated and infected people based solely on the constellation of different antibodies proved to be unreliable due to measurement uncertainties,” write the RKI and DIW in a statement.
The researchers write that the low infection rate is a success of the measures
From the data collected on previous infections from the questionnaires, the research group concludes that around ten percent of adults, eleven percent of 14 to 17 year olds and seven percent of those over 60 years of age had been infected with Sars-CoV-2 by the turn of the year had. “This relatively low infection rate after a pandemic of around two years can be seen as a success of the measures to contain the pandemic,” writes the group. However, the survey has not yet been able to record the extreme waves of infection that have been triggered by the omicron variant since the beginning of the year. The researchers therefore assume that the seroprevalence in the population has continued to increase since then, especially since the vaccination rate has also increased.
The team recognizes that the data collected is likely to be biased in some respects. The group considers it likely “that more people took part in this study who were vaccinated and also followed other measures to contain the pandemic than people who did not take part”. This is supported by the fact that 94 percent of those surveyed were vaccinated at least once. According to vaccination rate monitoring, this proportion was around 86 percent of the total population at the turn of the year. “It must therefore be assumed that in this study the proportion of vaccinated people in the population is overestimated and the proportion of infected people is underestimated,” writes the group. The extent of the distortion cannot be precisely determined.
The team writes that it is not possible to make any statements about how well people with antibodies against Sars-CoV-2 in their blood are protected from infection with the virus or a severe course of the disease. Further analyzes of the collected data are to follow. One hopes to come across markers in the blood that can provide information about a person’s immune protection. A further seroprevalence study is not planned for the time being. In view of a proportion of 90 percent with antibodies in the blood – what should come as a surprise at the moment?