In a recent study published in the Life Journal, researchers investigated the variation in the clinical and demographic characteristics of acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the persistence of long coronavirus disease (long COVID) across different strains of SARS-CoV-2.

Study: Prevalence of Long COVID Symptoms Related to SARS-CoV-2 Strains. Image Credit: JosieElias/Shutterstock.comStudy: Prevalence of Long COVID Symptoms Related to SARS-CoV-2 Strains. Image Credit: JosieElias/


Long COVID comprises the constant or recurrent presentation of symptoms such as chronic fatigue, dyspnea, myalgia, difficulty sleeping, chest pain and palpitations, and depression that occur after recovering from an acute SARS-CoV-2 infection.

Long COVID's physical and mental symptoms have been shown to affect the quality of life, with low energy levels and pain preventing the patients from conducting their daily activities.

Patterns similar to long COVID have also been observed after infections with Epstein-Barr virus, Middle East respiratory syndrome virus, and influenza virus, with patients with a history of depression or anxiety and female patients showing greater prevalence.

Furthermore, over the course of the coronavirus disease 2019 (COVID-19) pandemic, a plethora of SARS-CoV-2 variants have emerged, some with increased virulence and transmissibility and others with novel mutations that allow them to escape vaccine-induced immunity.

However, whether the long COVID symptoms differ based on the SARS-CoV-2 variant remains unclear.

About the study

In the present study, the researchers assessed the clinical and demographic characteristics, infection severity, and persistent symptoms that characterize long COVID, such as fatigue, myalgia, and dyspnea among cohorts of COVID-19 patients in Italy during the SARS-CoV-2 waves between March 2020 and 2022.

Patients above the age of 18 years diagnosed with symptomatic SARS-CoV-2 infections confirmed using positive swab tests were eligible to participate in the study, and patients were excluded if they could not read and provide informed consent.

Data were gathered during a baseline visit, which occurred in the 18 months following a SARS-CoV-2 infection, with a follow-up visit after six months.

Baseline information was gathered on the severity of the SARS-CoV-2 infection, comorbidities, body mass index (BMI), smoking habit, and long COVID symptoms such as fatigue and dyspnea and their impact on the quality of life. The age-adjusted Charlson score was used to categorize a list of comorbidities as low, high, or very high.

Hospitalization, mechanical ventilation, and oxygen supplementation requirements were used to classify COVID-19 severity on a scale of one to four, with one indicating no hospitalization and four indicating hospitalizations with the need for Intermittent Mandatory Ventilation.

Fatigue was assessed using a self-reported questionnaire that examined physical and mental fatigue. In contrast, another self-reported questionnaire assessed aspects such as self-care, mobility, pain or discomfort, depression or anxiety, and the impact on usual activities to evaluate the changes in the quality of life.

The variants were classified according to the waves during the COVID-19 pandemic, with the ancestral or classical strain causing infections between March and July 2020 and the Alpha variant responsible for infections between August 2020 and January 2021.

Infections between February and June 2021 were attributed to the Alpha, Beta, Gamma, and Delta variants, but the Delta variant was considered solely responsible for infections between July and November 2021. All infections after December 2021 till the end of the study period in March 2022 were classified as SARS-CoV-2 Omicron infections.


The results reported no significant differences in the fatigue and dyspnea symptoms during long COVID associated with any SARS-CoV-2 variants. However, when the changes in quality of life were examined across long COVID patients infected with different SARS-CoV-2 variants, the lower quality of life due to pain was more prevalent among patients infected with the classical or ancestral SARS-CoV-2 strain.

The researchers believe that the presence of reactive oxygen species and inflammatory cytokines can pathophysiologically explain persistent long COVID symptoms.

Furthermore, the multi-variable analysis indicated that persistent symptoms during long COVID are positively associated with the number of symptoms during the onset of the acute SARS-CoV-2 infection, which could be linked to a persistent state of inflammation.

Additionally, while the persistent symptoms of pain, reduced mobility, and ability to conduct daily activities had improved between the baseline and follow-up visits, the symptoms of anxiety and low levels of self-care were not seen to improve between baseline and follow-up.


Overall, the findings indicated that apart from the change in the quality of life associated with pain, persistent long COVID symptoms were not seen to change based on SARS-CoV-2 infections with different variants of concern.

The reduced quality of life due to pain was observed to be more prevalent among patients who were infected with the ancestral SARS-CoV-2 strain.

Additionally, all persistent long COVID symptoms except anxiety and reduced self-care improved between baseline and six-month follow-up visits.

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