ICVS Post-COVID-19 Condition Study Published in Nature Communications

An ICVS team of researchers, from the School of Medicine, saw their work recognized and published in the prestigious journal Nature Communications, where the potential differentiators between individuals who have or do not have the post-COVID-19 Condition were explored.

Post-COVID-19 Condition occurs in individuals with a history of SARS-CoV-2 infection at least 3 months after the COVID-19 episode and is characterized by symptoms lasting at least 2 months that cannot be explained for an alternative diagnosis. The most common symptoms include fatigue, shortness of breath, difficulty in cognitive tasks, memory lapses, depression/anxiety, among others, which can range from mild to completely disabling. Symptoms can appear soon after the cure of COVID-19 and persist over time, or appear only later, and their intensity can fluctuate.

Despite the existence of studies with disparate results in the rate of patients affected by this condition (which will vary between 10 and 60% of all patients infected with SARS-CoV-2), age and hospitalization, especially in Intensive Care Units, are considered risk factors for the persistence of symptoms. However, the Post-COVID-19 Condition can arise in patients who have shown mild symptoms or who have not had any complaints. Although, fortunately, most people have a spontaneous resolution of their complaints, the assessment of users with a suspected Post-COVID-19 Condition must be adapted to the individual user context, the main clinical manifestations and the involvement of different systems and organs.

In this work, the immune response of dozens of individuals who did or did not develop the Post-COVID-19 Condition six months after the infection caused by SARS-CoV-2 was characterized. This strategy made it possible to identify, in patients with the post-COVID-19 Condition, an alteration in the immune response that suggests viral persistence in the mucous membranes.

Ricardo Silvestre, ICVS researcher at the School of Medicine, explains that “our study suggests that we have two markers that are potential differentiators between patients with post-COVID-19 or who do not have a post-COVID-19 condition that could still potentially be used for diagnosis. The persistence of the virus in the mucous membranes induces a dysregulated response in patients with the post-COVID-19 condition. We also identified that a more pronounced inflammatory condition during the acute phase of the disease is related to the development of a post-COVID-19 condition”.

“These markers can improve the definition of the Post-COVID-19 Condition itself, making the diagnosis more accurate and objective. It is also essential to understand the mechanisms of the disease, its natural course, potential sequelae, as well as the development of a tool that helps to identify patients at risk after hospital discharge. This tool would represent a great asset for patients, for managing resources and for planning interventions in health systems”, adds Ana Mendes–Frias, a researcher at ICVS, who is part of the team for this study.

André Santa Cruz, doctor at Hospital de Braga, professor and researcher at the School of Medicine, emphasizes that “due to its high frequency and its impact on the lives of patients and their families, the post-COVID-19 condition is a challenge for health systems, as well as the medical and scientific community. Better knowledge of the disease can translate into treatments that are different and more effective than current treatments. In this way, our study allows a better understanding of the pathophysiology associated with the development of the post-COVID-19 condition, paving the way for an evaluation of the treatment of these patients with antiviral drugs and contributing to the future development of predictive biomarkers”.

This study was carried out in patients who had not yet been vaccinated, however it is currently confirmed that vaccination reduces, by a considerable percentage, the possibility of contracting the Post-COVID-19 Condition.