google translation of the interim report, released on the 9th April. The full report not yet available.
Preliminary results and conclusions of the COVID-19 case cluster study (Gangelt municipality)
Prof. Dr. Hendrik Streeck (Institute of Virology)
Prof. Dr. Gunther Hartmann (Institute for Clinical Chemistry and Clinical Pharmacology, Spokesman for the Cluster of Excellence ImmunoSensation2)
Prof. Dr. Martin Exner (Institute for Hygiene and Public Health)
Prof. Dr. Matthias Schmid (Institute for Medical Biometry, Computer Science and Epidemiology)
University Hospital Bonn, Bonn, April 9, 2020
Background: The municipality of Gangelt is one of the most affected places in Germany by COVID19 in Germany. The infection is believed to be due to a carnival session on February 15, 2020, as several people tested positive for SARSCoV2 after this session. The carnival session and the outbreak of the session are currently being examined in more detail. A representative sample was drawn from the community of Gangelt (12,529 inhabitants) in the Heinsberg district. The World Health Organization (WHO) recommends a protocol in which 100 to 300 households are sampled depending on the expected prevalence. This sample was coordinated with its representativeness with Prof. Manfred Güllner (Forsa).
Aim: The aim of the study is to determine the level of the SARS-CoV2 infections (percentage of all infected) that have been undergoing and are still occurring in the Gangelt community. In addition, the status of the current SARS-CoV2 immunity is to be determined.
Procedure: A form letter was sent to approximately 600 households. A total of around 1000 residents from around 400 households took part in the study. Questionnaires were collected, throat swabs were taken and blood was tested for the presence of antibodies (IgG, IgA). The interim results and conclusions of approx. 500 people are included in this first evaluation.
Preliminary result: An existing immunity of approx. 14% (anti-SARS-CoV2 IgG positive, specificity of the method>, 99%) was determined. About 2% of the people had a current SARS-CoV-2 infection determined using the PCR method. The overall infection rate (current infection or already gone through) was approximately 15%. The mortality rate (case fatality rate) based on the total number of infected people in the community of Gangelt is approx. 0.37% with the preliminary data from this study. The lethality currently calculated by the Johns-Hopkins University in Germany is 1.98% and is 5 times higher. Mortality based on the total population in Gangelt is currently 0.15%.
Preliminary conclusion: The 5-fold higher lethality calculated by Johns-Hopkins University compared to this study in Gangelt is explained by the different reference size of the infected. In Gangelt, this study includes all infected people in the sample, including those with asymptomatic and mild courses. The proportion of the population that has already developed immunity to SARS-CoV-2 is about 15%. This means that 15% of the population in Gangelt can no longer become infected with SARS-CoV-2, and the process has already been started until herd immunity is reached. This 15 percent share of the population reduces the speed (net reproduction number R in epidemiological models) of a further spread of SARS-CoV-2.
By adhering to stringent hygiene measures, it can be expected that the virus concentration in the event of an infection in a person can be reduced to such an extent that the severity of the disease is reduced, while at the same time developing immunity. These favorable conditions do not exist in the event of an extraordinary outbreak event (superspreading event, e.g. carnival session, apres ski bar Ischgl). With hygienic measures, favorable effects with regard to all-cause mortality can also be expected.
We therefore strongly recommend implementing the proposed four-phase strategy of the German Society for Hospital Hygiene (DGKH). This provides the following model:
Phase 1: Social quarantine with the aim of containing and slowing down the pandemic and avoiding an overload of the critical care structures, especially the health care system
Phase 2: Beginning withdrawal of the quarantine while ensuring hygienic framework conditions and behavior.
Phase 3: Abolition of the quarantine while maintaining the hygienic framework
Phase 4: State of public life as before the COVID-19 pandemic (status quo ante).
(DGKH statement can be found here:
Note: These results are preliminary. The final results of the study are published