The infection is over, but the suffering continues: Many people still have health problems months after contracting Covid 19. A study led by Dresden researchers provides data for Germany.

Millions of people around the world report long-term effects of a corona infection and describe a wide variety of symptoms. So far it has been largely unclear to what extent children and young people are affected by post-Covid. A study published in the journal “PLOS Medicine” under the direction of the University Hospital Dresden now shows that some of them still have to struggle with symptoms for months – albeit significantly less frequently than adults. The causes of the post-Covid syndrome remain unclear.

The German patient guidelines define complaints that persist for more than four weeks after the corona infection as long-Covid, and as post-Covid they last longer than twelve weeks.

For the study, the scientists used data from six German health insurance companies to determine how often certain long-term symptoms occurred in Covid 19 cases confirmed by a PCR test. Overall, the data set of the study included almost half of the German population. Information from 11,950 children and adolescents up to the age of 17 and from 145,184 adults (up to the age of 49) with Covid-19 disease in 2020 was evaluated. In addition, the researchers selected five corresponding controls without a reported corona infection for each person from the cohort examined. Then it was compared how much more frequently certain symptoms occurred at least three months after infection in those affected by Covid 19.

The result: Overall, the probability that children and adolescents suffering from Covid-19 during the first wave of the pandemic would have documented health problems three months or more after infection was 30 percent higher than in the control cohort.

The adolescents complained most frequently about being unwell and exhausted, coughing, pain in the neck and chest area, but also adjustment disorders. Among adults, the rate of those who received medical diagnoses due to physical and psychological symptoms three months after infection was 41 percent higher than among children and adolescents. Long-lasting disturbances in smell and taste, fever, shortness of breath (dyspnea) and cough were noted in the medical records.

The authors of the study, which include Lothar Wieler, President of the Robert Koch Institute (RKI), summarize: “We found that the Covid-19 diagnosis was associated with a higher long-term demand for health services, which reflected in outpatient and inpatient diagnoses of a wide range of outcomes more than three months after confirmed Sars-CoV-2 infection. While children and adolescents appear to be less affected than adults, these results are statistically significant for all age groups.”

For Winfried Kern from the Clinic for Internal Medicine at the University Hospital in Freiburg, the consideration of adolescents with a large control group and the relatively long observation period are the strengths of the Dresden work. “The study can describe very well how many people go to the doctor more often after a Covid infection than the control cohort because of symptoms,” he said in an independent assessment by the German Press Agency. However, the study design also means that only the complexes of complaints identified through a doctor’s contact were recorded: “Fatigue, exhaustion and memory problems and poor concentration are probably not so dominant in this study for this reason.”

In addition, the use of medical services is not an exact indicator of limitations in everyday functionality, says Kern. The infectiologist himself led a post-Covid study in Baden-Württemberg, the results of which were recently published in the British Medical Journal. This showed that around a quarter of the 12,000 study participants aged between 18 and 65 years suffered from significant long-term consequences six to twelve months after a corona infection – and this severely restricted their quality of life and ability to work. In a follow-up study, Kern’s research group is currently comparing the extent to which corona sufferers with and without post-Covid symptoms differ in order to track down possible biomarkers. First studies suggest that certain blood proteins, but also a low cortisol value could be measurable parameters.

Determining biomarkers could also help to explain the causes of the long-term effects of Covid-19. According to Winfried Kern, damage to the nervous system is also discussed in addition to circulatory disorders. If, for example, the autonomic nervous system were affected, which regulates circulation and blood pressure, among other things, that would explain symptoms such as fatigue. “However, basic research is still necessary here,” emphasizes the infectiologist. However, there are already indications that the post-Covid risk of an omicron infection is lower.

In addition to the many positive points of the study, other experts also see shortcomings. “Infections up to mid-2020 were taken into account, which means that neither infections caused by the omicron variant nor the effects of the Sars-CoV-2 vaccinations were recorded,” says Peter Berlit, Secretary General of the German Society of Neurology (DGN), a resident neurologist and co-author of the S1 guideline Long/Post-Covid.

Clara Lehmann, specialist in internal medicine, infectiology, travel medicine and head of the infection protection center at Cologne University Hospital, made a similar statement: “The mixing of inpatient (even intensive care) and outpatient cases distorts the picture. In addition, the follow-up is relatively short at only six months. All data relate to a time when the origin variant of Sars-CoV-2 (Wuhan) was predominant, which was a much more aggressive virus strain than strains circulating today. In addition, it must be mentioned that this cohort consists of unvaccinated people, which we currently no longer find in this form.”

The last two points were mentioned in one sentence in the discussion, but in their opinion they were very central in the evaluation of the results.

Nevertheless, both emphasize that post-Covid is a relevant postviral syndrome and that it is becoming clear that long-Covid is an important issue for both adults and children – even after a mild course of the acute infection.

Questions such as those about post- and long-Covid according to Omikron will be discussed next week at the first congress of the newly founded Long-Covid physicians’ association, which will take place on November 18th and 19th in Jena under the patronage of Thuringia’s Prime Minister Bodo Ramelow (Die Left) and Federal Minister of Health Karl Lauterbach (SPD). Possible forms of therapy will also be a topic there, but there are still major research gaps, as expert Kern emphasizes: “As long as the exact causes are not known, therapy options remain experimental.”