Due to the variety of symptoms and the lack of diagnostic biomarkers and tests, the diagnosis of post-COVID syndrome is currently a diagnosis of exclusion. It is very cost-intensive, requires a great deal of effort and close and efficient collaboration between GPs and specialists. There is therefore a need for easy-to-use and standardised tools, especially in primary care, in order to be able to make an informed decision on further diagnostics. The scientists from the Centre for Cardiology and the Centre for Thrombosis and Haemostasis (CTH) at the Mainz University Medical Centre have now developed such an instrument in the form of the test.
Specific long-term symptoms identified
To develop the test, the scientists analysed data from over 900 people from the population-based Gutenberg COVID-19 Study conducted by the Mainz University Medical Centre. In the course of this study, people with known and unknowing SARS-CoV-2 infection and a control group without previous SARS-CoV-2 infection were examined between October 2020 and January 2022. People were asked about new or worsening symptoms since their SARS-CoV-2 infection or since the start of the pandemic. Around a third of the study participants included in the analysis with previous known SARS-CoV-2 infection and a quarter of respondents with previous undetected SARS-CoV-2 infection reported symptoms that persisted for more than six months and were therefore defined as long-term symptoms. However, around a quarter of the participants in the control group with no previous SARS-CoV-2 infection also reported long-term symptoms. This emphasises that the symptoms in the context of post-COVID are not specific to the syndrome and therefore no diagnosis can be made. However, it also highlights the need for data-based test instruments to support further diagnostic clarification.
Using machine learning, the researchers were able to identify 21 long-term symptoms that differed between people with and without previous SARS-CoV-2 infection. The results were validated using data from an independent population cohort - the SentiSurv RLP surveillance and early warning system.
Test to be made available in the form of a web-based questionnaire
The symptoms identified in this way form the basis for the new test, which can be used in future by healthcare professionals and representatives of healthcare professions. It will be made available in the form of a web application. ‘As the test is based solely on the profile of the patient's symptoms, it can be used quickly and easily in everyday practice,’ emphasises study leader Prof. Dr Philipp Wild. ‘It is particularly suitable for use by GPs, who are the first point of contact for patients with suspected post-COVID syndrome.’
What the test can do - and what it can't
‘The test has a high sensitivity and can therefore rule out the presence of post-COVID syndrome with a high degree of probability in the event of a negative test result,’ explains Philipp Wild. "This is helpful for clarifying the cause and for the treating doctor's decision regarding the further diagnostic procedure. The test should therefore always be interpreted in the context of other clinical data and based on the doctor's assessment and not used as the sole basis for decision-making."
Conversely, according to Wild, this means that the test is not suitable for diagnosing post-COVID syndrome due to its characteristics, as many people without the syndrome could also have a positive test result. In the event of a positive result, the treating physicians must therefore still carry out the usual further diagnostic clarification. ‘By selecting the symptoms present, we can determine a probability and thus provide an indication of the extent to which the symptoms are related to post-COVID,’ adds Rieke Baumkötter, first author of the publication and epidemiologist in Philipp Wild's working group.
The test was developed for both patients with previous symptomatic and people with previous asymptomatic SARS-CoV-2 infection. It can only be used in adults, but not in children and adolescents, as no data is available for them.
About post-COVID syndrome
According to estimates by the Robert Koch Institute, six to 15 per cent of the population are affected by the long-term consequences of COVID-19. Post-COVID syndrome (PCS) refers to health complaints that persist for more than three months after an acute infection with the SARS-CoV-2 coronavirus and cannot be attributed to any other cause. The impairments are very diverse and can affect the lungs, cardiovascular system, muscles, intestines, kidneys, cognitive abilities and mental health, among other things. The most common PCS symptoms include persistent fatigue, which can manifest as myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), shortness of breath or concentration and memory problems. PCS can severely affect the quality of life and everyday life of those affected. The causes of the disease have not yet been sufficiently deciphered. Treatment has therefore so far been purely symptomatic.
Original publication: Shi Y. et al., Persistent symptoms and risk factors predicting prolonged time to symptom-free after SARS‑CoV‑2 infection: an analysis of the baseline examination of the German COVIDOM/NAPKON-POP cohort, Infection, May 2023.
Source: Presse release University Medical Centre
