Coronavirus Update FAQ 14

Long-term outcome after acute Covid-19 infection

Author: Stefan Lindgren, Sweden

The Covid-19 pandemic still persists, although the consequences for patients and societies have diminished dramatically after successful vaccination of the populations. The burden of disease on individuals and societies is still high in countries where the proportion of vaccinated individuals is low. However, new variants of the virus are likely to appear and the duration of the vaccine protection is uncertain. So, we will probably have to live with the threat from the Covid-19 virus and need for revaccination for a long time.

Data is accumulating regarding long-term consequences after Covid-19 infection. Although the majority recovers completely, quite a few experience persistent symptoms for many months or even longer. The clinical outcome is more clearly described and understood if we consider two categories of patients; those with severe Covid-19 in need of hospitalization or even intensive care and those with clinically milder disease, managed outside the hospital. Also, the virus variants must be considered, which is particularly obvious now with the apparent milder course of disease with the omicron variant.

The vast majority of patients with mild acute disease recover rapidly and completely, particularly those who are fully vaccinated. However, some patients experience disturbing symptoms for a long time. The frequency of this protracted course of disease is still not known and the same is true for the mechanisms. This is underlined by the lack of clear correlation between subjective symptoms and objective findings in many of these individuals. Therefore, specialized outpatient clinics with highly specialized physicians and research competence are established to shed further light on this puzzling condition. The symptoms are dominated by fatigue, joint- and ´muscular pain and weakness, shortness of breath and rapid heart frequency even after minor physical effort, low physical capacity, gastrointestinal problems and loss of appetite, mental tiredness and cognitive problems. Although these problems gradually diminish and usually disappear over time, they may persist for a long time and have severe personal and societal consequences. Reassurance and support remain the cornerstones of treatment. But more research is necessary to understand the reasons behind long-term symptoms in individuals with mild acute infection. The case of long Covid is not unique as many severe infectious diseases in particular viral ones provoke similar long-term consequences in some patients.

Recently, a Dutch publication reported clinical outcomes among 246 patients with 1-year survival following intensive care treatment for Covid-19. The patients were evaluated one year after treatment in an intensive care unit for a median length of 18 days. 74% of the patients reported persistent physical symptom, 26% mental symptoms and 16% cognitive symptoms. Overall, 31% of the patients reported being frail and 56% experienced fatigue. Two-thirds reported new physical symptoms. The most frequent were general weakness, joint stiffness, joint pain, muscle weakness and myalgia. Among mental problems, anxiety and depression dominated. Overall, 30% reported symptoms from 2 domains (physical, mental and cognitive) and 10% from all three domains. In addition, 58% of the survivors who were employed before admission to the intensive care unit reported work-related problems such as working less hours or still on sick leave.

Taken together, our current knowledge around long-term consequences after Covid-19 infection is that these are substantial and may have severe consequences. The good news is that most patients rapidly recover completely and that those with long-term symptoms gradually improve over time and most of them will also recover completely. The problems related to patients with severe Covid-19 are more easily understood in relation to documented organ damage, while more needs to be learned about the mechanisms behind long-term symptoms in patients with mild disease. For that reason, post-Covid-19 outpatient multi professional clinics with highly specialized competencies are established in many countries to assist those patients and promote research. Vaccination protects also against long-term consequences of disease. In light of the still ongoing spread of Covid-19 virus and the expected development of new virus variants, we must continue to support full vaccination, stay at home when ill and avoid crowding to minimize long-term consequences after acute Covid-19 infection.