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Weekly Update (May 29, 2020)

Current Update: Clarification
 
Please note that the German newspaper Münchner Merkur (front page story, dated May 13th, 2020) and TZ Online (see article, dated May 22nd, 2020) have misleadingly reported that we have published an official estimated prevalence of 5%. Contrary to the news that they are reporting, we have not published any interim results to date.
 
Professor Michael Hoelscher has already commented on the current state of research stating that, “We are currently examining the blood samples from the study participants. As the accuracy of the testing method is still uncertain, further investigation is necessary to determine the actual status of each individual sample. For this reason, it would be irresponsible to communicate any preliminary results. We are currently sticking to our original estimate that the infection rate is in the lower single-digit percentage range.”
 
To see the current progress of the study, please find all official information below.


Progress of the study: Current information on recruitment status

Using the random route procedure, we have identified 3,000 households within the Munich city area. After the start of our study on April 6th 2020, we have visited around 2,800 of the recruited households (as of May 29th, graphic based on numbers of May 26th). Since the studies inception, we have successfully trained over 60 university students via our intensive training program. Per day, between 10 to 120 households are recruited. We expect to reach our total of 3,000 households for the study by mid-June 2020 at the latest.
 
Contrary to the expected average household size of 1.5, we currently have an average household size of 2.05. We therefore expect a total of just over 6,000 participants.
 
So far, we have encountered around 65% of the selected households on our random walks, of which around 80% of the households have opted to take part in the study — a very good participation rate, which should give us a very representative sample of the scale of COVID19 infection and spread in Munich.


20200526_Recruitment_data_EN 


How does the evaluation work and when can results be expected?

We want to thank you for your willingness to participate in our study as one of the randomly selected households. The recruitment of the 3,000 households (approx. 5,000 - 6,000 individuals) in Munich is expected to be completed by the mid of June 2020. Until then, all participants will have blood samples taken and their basic personal information collected via questionnaire on the web app. As a participant your health will be monitored via regular blood tests, which will take place at regular intervals for several weeks and surveys which will continue over the entire duration of the study.
 
The detection of antibodies against the new SARS-CoV-2 is a sign of a surviving infection. In order to test for this, serological tests —so-called enzyme-linked immunosorbant assays (ELISA)— are currently being carried out in the KoCo19 laboratory at the Division of Infectious Diseases and Tropical Medicine, in Munich. Even though the available antibody tests already have a very high specificity (over 98%), they still have an error rate of approximately two to three percent. This means that for every 100 tests there are at least two unspecific reactive results (often simply referred to as “false positive”): where a sample shows as positive despite there not being any SARS-CoV-2 antibodies (or infection) present. This small rate of unspecific reactive results can lead to massive statistical bias in relation to the overall result.


A preprint of the method paper is available at: https://www.medrxiv.org/content/10.1101/2020.04.28.20082743v1


To get meaningful results —i.e. to describe how many people have actually been infected with SARS-CoV-2— the results must be confirmed through additional tests. For this purpose, a so-called neutralization test is carried out on cell cultures for SARS-CoV-2 there is currently no routine procedure for this. The neutralization test provides information as to whether the detected antibodies in the blood actually make the novel coronavirus harmless. Moreover, the ability to rely on any one test result will also increase through repeated testing of the participants over the course of the study. In order to carry out a more precise determination, we also carry out further complex tests: tests for other circulating coronaviruses can provide information on the cross-reactivity of antibodies and tests using “peptide arrays”, which can provide information on which structures of SARS-CoV-2 exactly dock the antibodies detected, are two such examples.
 
In order to be able to make reliable statements and increase the certainty regarding the exact data of the overall KoCo19 cohort, we ask you to be patient. We will communicate the interim results of the first survey phase of KoCo19 to the public at the beginning of July after detailed analysis.
 

As of May 29th, 2020, subject to modifications