To date, more than 692 million individuals have been infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic.

Most individuals infected with SARS-CoV-2 experience mild to moderate symptoms that do not require hospitalization. In some cases, COVID-19 symptoms persist for a prolonged period after initial recovery from the infection. This condition has been termed as post-COVID-19 syndrome or long COVID.

Study: Impaired health-related quality of life in long-COVID syndrome after mild to moderate COVID-19. Image Credit: tommaso79 / Shutterstock.com

Background

Some common long COVID symptoms include headache, anosmia, fatigue, and dyspnea. Previous studies have identified some factors that may be responsible for long COVID including prolonged immune activation due to the persistence of SARS-CoV-2 in the body and lymphocyte dysfunctions similar to autoimmune diseases. 

A high degree of variance has been observed while estimating the prevalence of long COVID as a result of different recruitment methods and time points of assessments across studies. Overall, there remains a lack of information on the pathophysiological mechanisms responsible for long COVID.

The World Health Organization (WHO) has defined quality of life as “an individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns”.

Several studies have evaluated how chronic diseases influence health-related quality of life (HRQoL).

Previous research has shown that HRQoL is impaired after hospitalization due to severe SARS-CoV-2 infection. However, these studies did not explain how HRQoL is affected due to long COVID after a mild or moderately acute infection. 

About the study

A recent Scientific Reports study determined HRQoL in a Swiss cohort comprised of patients with long COVID after experiencing mild to moderate SARS-CoV-2 symptoms. The University Hospital of Zurich formed an interdisciplinary outpatient clinic for patients with long COVID symptoms. Each patient completed questionnaires regarding HRQoL after consultation. 

Patients who suffered from long COVID or were at risk of developing long COVID after mild or moderate infection were selected for this study. These patients suffered either systemic symptoms, such as recurrent fever and fatigue, or organ-specific symptoms like palpitations and cough. Patients who required prolonged hospitalization, admission to the intensive care unit (ICU), or supplemental oxygen during the acute phase of COVID-19 were excluded from the cohort. 

Study findings

A total of 112 long COVID patients identified between February 2021 and August 2021 completed the HRQoL questionnaires. Most of the participants were women whose median age was 43 years and body mass index (BMI) value was 24.4 kg/m². 

Some of the patients suffered from asthma, pre-pandemic mental health issues, or had at least one comorbidity. Most patients experienced a mild acute SARS-CoV-2 infection. Long COVID primarily impacted physical health as compared to mental health.

Mechanistically, long-lasting COVID-19 symptoms after severe and mild infection differ significantly. Most patients with long COVID that arises following a mild infection were found to suffer from issues related to pain and anxiety, whereas their  mobility was not significantly affected.

The findings of this study were compared with data on physical and mental health retrieved from a Swiss cohort that was developed during the first lockdown in Switzerland (CoWell study). During the second and third COVID-19 waves in Switzerland, similar degrees of physical and mental impairments were observed in patients who had recovered from SARS-CoV-2 infection. Notably, pandemic-related restrictions that aimed to prevent further spread of SARS-CoV-2 may have contributed to some of these symptoms.

Consistent with these observations, one previous study reported a reduction in all health domains after mild, moderate, or severe acute COVID-19. The same degree of mental and physical health-related long COVID symptoms manifested after severe and mild/moderate COVID-19.

Respiratory symptoms like dyspnea had a greater impact on the patient’s physical activity. However, most of the patients in the current study exhibited lower intensity and/or frequency of breathing symptoms. Notably, as compared to men, females were at a higher risk of developing long COVID after mild/moderate SARS-CoV-2 infection.

Conclusions

The current study is the first to compare HRQoL in patients suffering from long COVID after mild to moderate SARS-CoV-2 infection between pre-pandemic and pandemic cohorts.

Long COVID symptoms after mild/moderate SARS-CoV-2 infection affected the quality of life in this group of patients. Thus, long COVID increased the overall disease burden.

Future studies are needed to determine how long COVID affects social and economic conditions.