What is Long COVID?

‘Long COVID’ refers to longer-term health impairments following a SARS-CoV-2 infection that are present beyond the acute phase of the sickness phase of four weeks (see S1 Guideline Long/ Post-COVID). The symptoms may begin during the acute phase of the disease and continue for an extended period. Alternatively, they may appear or return weeks or months after the infection. The term ‘post-COVID condition’ or ‘post-COVID syndrome’ (see preliminary WHO case definition) is used when symptoms are either still present at least 12 weeks and longer after the acute infection or appear anew after this period and cannot be explained otherwise. In the following, the term ‘Long COVID’ is used to refer to long-term health consequences of a SARS-CoV-2 infection, as this covers the entire period beyond the acute phase of the disease. For health complaints that explicitly persist for more than 12 weeks, the term ‘post-COVID-19 condition’ is used.

People with Long COVID report a wide range of health complaints and symptoms, that vary widely in their clinical characteristics, severity and progression. These symptoms may affect different organ systems and have different causes. These include a variety of physical, cognitive, and psychological symptoms, which may appear alone or in combination and can negatively affect a person’s daily functioning and quality of life. Additionally, specific organ damage or the development of new chronic conditions are also possible. Based on current knowledge it is assumed that Long COVID is not one consistent cluster of symptoms – thus, its underlying mechanisms are insufficiently understood so far, which complicates the diagnostic and treatment of long-term health consequences. Therefore, an intensive and continuous collaboration between basic research, clinical and epidemiological research is important to develop and implement effective strategies for prevention, early detection and treatment of Long COVID. For people who are severely and persistently affected by Long COVID (i.e. due to myalgic encephalomyelitis/chronic fatigue syndrome, ME/CFS) comprehensive health care including psychosocial support needs to be ensured.

Follow-up project: Post-acute health consequences of COVID-19 (Post-COVID-19-II)

In September 2024, the follow-up project "Post-acute health consequences of COVID-19 - Follow-up project" funded by the Federal Ministry of Health, was launched. The goals are to continue the systematic review of epidemiological data and the public health impact of Long COVID, to further expand the public health research network on Long COVID and to conduct research on common health complaints associated with Long COVID in adults in Germany.

Further activities at the RKI regarding Long COVID

During the pandemic, the RKI conducted interdepartmental studies to monitor the spread of infection and the health status of the population. These include among others the antibody studies 'Corona-Monitoring-Local' (CoMoLo) and 'Corona-Monitoring-Nationwide' (CoMoBu), the survey 'German Health Interview Survey for Children and Adolescents' (KIDA), the COALA module of the Corona day-care centre study. From mid-2021, questions about Long COVID were incorporated into the studies. This allowed for comparisons of people with and without SARS-CoV-2 infection in terms of symptoms, quality of life, use of medical care and health-related restrictions in everyday life. The analysis of symptoms possibly related to Long COVID was also included in the COViK-Study, a hospital-based case-controlled study regarding the effectiveness and safety of COVID-19 vaccines.

In addition, the RKI continuously compiles the scientific evidence on Long COVID to support the scientific communication with the professional public (e.g., FAQ on Long COVID) as well as the BMG Long COVID Initiative (Federal Ministry of Health). More comprehensive, systematic evidence syntheses are also carried out in cooperation with external partners.

From the end of 2021 to the end of 2023, the Federal Ministry of Health-funded project 'Post-acute health consequences of COVID-19 - Post-COVID-19' bundled interdepartmental activities on Long COVID at the RKI. It facilitated the continuation of public health research projects, expanded scientific communication, and strengthened scientific networks between the RKI and other national and international partners.

Further information:

S1 Guideline Long/Post-COVID (in German)

WHO clinical case definition of post COVID-19 condition

WHO clinical case definition for post COVID-19 condition in children and adolescents

The RKI cannot provide individual medical advice. Further information and support services are provided within the FAQ on Long COVID