What are the long-term symptoms of SARS-CoV-2 infection?

By Namita MitraApr 4 2022Reviewed by Benedette Cuffari, M.Sc.

Recent studies have suggested that people who have recovered from the coronavirus disease 2019 (COVID-19) are at increased risk of developing various long-term symptoms including dyspnea, dysgeusia, anosmia, and asthenia. For these patients, the acute clinical presentation of COVID-19 is a strong determinant of whether they will experience certain persisting symptoms.

Due to the impact that these persistent symptoms can have on an individual’s quality of life, it is imperative to develop appropriate measures to treat or prevent symptoms of acute disease that could ultimately reduce the severity of these lingering symptoms associated with ‘long-COVID’.

Study: Persistent symptoms after SARS-CoV-2 infection: Long-term implications for health and quality of life. Image Credit: Dragana Gordic / Shutterstock.com

Background

There have been increasing reports of persistent physical and psychological symptoms after patients have recovered from COVID-19. These symptoms may persist irrespective of whether or not the acute phase required hospitalization.

A wide range of long-COVID symptoms have been reported, some of which include asthenia, dyspnea, dysgeusia/anosmia, cardiothoracic symptoms including cough, thoracic pain, and palpitations, as well as pain ranging from back pain and arthralgia to myalgia and headaches. Additionally, various digestive disorders hallmarked by nausea, diarrhea, constipation, and abdominal pain have also been reported, in addition to cognitive, and sleep disorders. Unfortunately, the pathophysiology of these long-COVID symptoms remains poorly understood.

A recent Lancet Regional Health – Europe study determines whether some of these symptoms are more specifically associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than with other conditions.

About the study

The longitudinal study was nested in the French CONSTANCES population-based cohort which is an epidemiological research infrastructure available for access to the epidemiologic research community. The extensive dataset utilized in the study was extracted from 25,910 individuals who fulfilled the inclusion criteria for the study.

All individuals who underwent serological testing for the presence of immunoglobulin G (IgG) to SARS-CoV-2 during the first wave of the pandemic were asked to fulfill three questionnaires. The first two questionnaires evaluated the various acute symptoms that the patients had experienced during the initial episode and classified participants based on whether or not they experienced a COVID-19-like illness during the first wave of the epidemic.

Participants were considered ‘Sero+’ or ‘Sero-’ if the serological test was positive or negative, respectively, for IgG to SARS-CoV-2. COVID-19-like illness was defined according to the European Centre for Disease Prevention and Control (ECDC). To this end, participants were considered “ECDC+” if they suffered at least one of the symptoms including dysgeusia/anosmia, dyspnea, fever, and cough for at least three days, in at least one of the first two questionnaires.

Between December 2020 and February 2021, a third follow-up questionnaire was used to collect information on persistent symptoms. The study population was then categorized into four groups, which included the ECDC+/Sero+ group, the ECDC+/Sero- group, the ECDC-/Sero+ group, and the ECDC-/Sero- group.

Persistent symptoms specific to COVID-19

Persistent symptoms were defined as symptoms and effects that lasted for at least two months after the infection. The researchers analyzed the association of prior COVID-19 (Sero+/Sero-) with the persistent symptoms mediated by their initial clinical presentation (ECDC+/ECDC-).

An adjusted logistic regression model showed that dyspnea, dysgeusia/anosmia, asthenia, and cognitive disorders were positively associated with positive serology, while abdominal pain or dermatological disorders were negatively associated.

While dysgeusia/anosmia (24%) and asthenia (20.3%) were persistent in the seropositive group, more than 80% of the symptoms reported during initial incidence had been resolved before the third follow-up questionnaire, regardless of the serological results.

Later, the mediation analysis demonstrated that the positive serology effect on each symptom was primarily mediated by the ECDC symptoms. This indicates that persistent symptoms associated with a Sero+ status were largely due to the acute COVID-19 symptoms.

Symptoms that were believed to be related to long-COVID, other than dysgeusia/anosmia, dyspnea, and asthenia, were found to be common persisting symptoms that were not specific to the causative agent.

Conclusions

The findings from the current study support future studies on the persistent symptoms associated with other common infections aside from COVID-19. Furthermore, the researchers suggest that future studies also assess changes in the severity of long-COVID symptoms over time to better understand the anticipated duration of long-COVID.

More research on the psychological or psychiatric symptoms related to COVID-19 is also needed, as these aspects of this disease have received relatively less attention from the research community. Such symptoms could be more long-lasting than the physical symptoms and, as a result, may have a more extensive impact on the affected patients’ quality of life.