Large-scale study on long and post covid: EPILOC study with 12,000 participants shows health impact

Ulm University

Following an infection with the coronavirus, about a quarter of all EPILOC study participants suffer from severe symptoms that affect their health as well as their ability to work for a period of six to twelve months. The population-based EPILOC study, financed by the state of Baden-Württemberg, included nearly 12,000 people previously infected with the SARS-CoV-2 virus between the ages of 18 and 65. It describes the type and severity of complications that appeared following an acute infection as well as their impact on quality of life and ability to work, even months later. The results were published in the renowned British Medical Journal on 13 October 2022.

“Even though we had anticipated such a trend, we were very surprised at how many young people with initially uncomplicated acute SARS-CoV-2 infections were at risk of long covid”, says Professor Winfried Kern from the Department of Internal Medicine II at the Freiburg University Hospital, who led the study. The universities of Heidelberg, Tübingen and Ulm were also involved in the study, which was conducted with the support of local health authorities in the vicinity of the participating universities.

Baden-Württemberg’s Minister of Science Petra Olschowski said, “The valuable insight on the type and nature of various complications in long-covid patients is an important step toward identifying desperately needed therapies. Viral diseases often have – especially at a young age – far-reaching consequences for the quality of life and ability to work. It is very important to us to get a grip on secondary illnesses resulting from COVID-19 before they manifest and, ideally, to gather useful information for treating other illnesses as well. Our institutes are working exceptionally well together in order to find answers to and tackle the complex challenges of long covid”. The state supported the EPILOC study between August 2021 and November 2022 with a total of €2.3 million. Funding is also planned for a continuation of the study (EPILOC II) for another two years starting in the winter of 2022.

Neurocognitive symptoms and fatigue impact ability to work

In particular, chronic fatigue/exhaustion, concentration difficulties or memory disorders, breathing difficulties and shortness of breath, altered sense of smell and anxiety and depression were the most commonly reported symptoms (frequency higher than 20 per cent) for six to twelve months following an acute SARS-CoV-2 infection (COVID-19). The first author of the study, Dr Raphael Peter from the Institute of Epidemiology and Medical Biometry at Ulm University, reports, “Neurocognitive impairments, along with chronic fatigue, were most strongly connected to reduced health and decreased ability to work with long covid. And even though we have to assume a possible bias owing to selective participation in the study, there is still a considerable burden of disease that remains”. The study calculated the minimum possible frequencies under the assumption that all of the non-participants did not have any complaints. As Dr Peter explains, this is “an extreme assumption, but the truth lies, as is often the case, somewhere between these values and the calculated frequencies of the participants”.

The authors of the study are convinced that the results will contribute to a better understanding of the personal risks and subsequential costs to society of long covid. They can also help in increasing the level of precision when implementing rehabilitation measures. Some of the participants have already been invited to the respective university hospital in order to study the illness more thoroughly and to further explain the mechanisms (EPILOC Phase 2). This should help in identifying and clarifying possible causes as well as the long-term course of the complications.

Raphael S. Peter, Alexandra Nieters, Hans-Georg Kräusslich, Stefan O. Brockmann, Siri Göpel, Gerhard Kindle, Uta Merle, Jürgen M. Steinacker, Dietrich Rothenbacher, Winfried V. Kern for the EPILOC Phase 1 Study Group. Post-acute sequelae of COVID-19 six to 12 months after infection: a population-based study. BMJ. DOI: 10.1136/bmj 2022 071050

Text:  Universitätsklinikum Freiburg
Translation: Kate Gaugler


Post covid patients being examined at Ulm UniversityMedical Centre (Photo: Eberhardt/Ulm University)