In a recent study published on the preprint server medRxiv*, researchers profiled post-coronavirus (COVID) syndrome (PCS) in several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants.
Study: profiling the post-COVID syndrome in different variants of SARS-CoV-2. Image credit: eamesBot/Shutterstock
background
SARS-CoV-2 is a highly contagious and rapidly evolving coronavirus (CoV). It has infected more than 572 million people worldwide since the initial cases of human transmission more than two years ago.
Investigations of self-reported symptoms significantly improved knowledge of SARS-CoV-2 throughout the pandemic and enabled the long-term impacts of COVID-2019 (COVID-19) to be followed beyond the hospital setting. Characterizing how PCS manifests in varied patterns is essential to enable individualized therapy for the most affected survivors.
According to the authors of the present research, no available research compares the pattern of PCS symptoms between the vaccination status of COVID-19 and different variants of SARS-CoV-2. Furthermore, no study attempted to characterize the PCS by reporting modeling of longitudinally acquired symptoms in a time-series data format.
About the study
The present study used a large sample with prospectively pooled longitudinal self-reported COVID-19 symptoms to establish symptom patterns for PCS among dominant SARS-CoV-2 variants in 2020 and 2021 and throughout the state of vaccination when infected. It aims to guide the prognosis of PCS and tailored management.
In the current prospective longitudinal cohort study, researchers examined data from 336,652 participants who provided periodic health reports using the COVID Symptom Study (CSS) mobile app. They used self-reported prospective data collected throughout the pandemic from a remarkably large cohort in the United Kingdom (UK) to conduct an unsupervised cluster assessment of community-based PCS patient symptoms.
The different symptom profiles of PCS patients across SARS-CoV-2 variants and vaccination status during the time of infection were identified by pooled assessment of time series data. Groups were subsequently characterized by symptom duration, prevalence, demographics, and comorbidities or preexisting conditions. In addition, the team studied how PCS clusters influenced the lives of affected people using an independent research sample with additional data from 140 people.
results
The study results revealed that participants reported being physically well approximately 30 days before they tested SARS-CoV-2-positive. Interestingly, 9,323 people later experienced Long-COVID, characterized by SARS-CoV-2 symptoms that continued for more than 28 days. In addition, 1,459 developed PCS, considered to have had symptoms of COVID-19 for more than 12 weeks.
The study discovered three main symptom profiles for people who experienced COVID-19 symptoms for 12 weeks or more. These profiles were consistent across the viral variants analyzed (Delta, Alpha and wild-type) and according to vaccination status; the only differences were the proportion of people who experienced each pattern and the total duration of symptoms. The authors found distinctive symptom patterns for PCS across and within SARS-CoV-2 variants. In addition, four endotypes were found for infections caused by the wild-type strain SARS-CoV-2, five for Delta and seven for Alpha.
A cluster of cardiorespiratory symptoms was discovered among all variants. Central neurological disorders were the subject of a second cluster, and cases with the most debilitating and severe multi-organ symptoms were associated with a third cluster. There were no more than two different phenotypes of gastrointestinal symptoms per virus strain. An independent research sample validated the existence of the three major clusters and assessed their functional influence.
Symptoms associated with the central neurological cluster included dysosmia/anosmia, brain fog, fatigue, depression, headache, and delirium. This symptom profile coincided with the second largest cluster of wild-type variants and the largest cluster of Delta and Alpha variants.
The second frequent group, the largest during the wild-type phase when no one was vaccinated, was related to cardiorespiratory symptoms. This cluster could indicate lung damage, discovered in other analyzes and suggested in the current research as chest pain and dyspnea. Finally, a third frequent cluster, found in all variants, was differentiated by myalgias, abdominal and inflammatory/systemic symptoms, as documented in other research focusing on PCS.
Conclusions
The researchers stated that the current study was one of the first large-scale investigations to establish a cluster of PCS symptoms among adults in an unsupervised manner.
The results of the study demonstrated the existence of several PCS, with shared characteristics between the SARS-CoV-2 variants in the symptoms and the mechanism of their evolution during the course of the disease. The scientists described subgroups of patients with particular post-COVID manifestations, which could signify various underlying pathophysiological processes.
The study found unique self-reported symptom evolutions, or clusters, in those with 12 or more weeks of persistent symptoms after SARS CoV-2 infection, adopting a data-driven methodology. Several clusters were detected across the three viral variants examined. However, three groups emerged characterized predominantly by specific symptom clusters (cardiorespiratory, central neurological and inflammatory/systemic) with shared characteristics.
The present study was relevant to post-COVID prognosis, revealing how long specific symptoms persist due to the time series element. These findings may help inform individualized diagnosis and therapy and care planning for PCS patients by policy makers. In addition, the current classification may help to understand the multiple mechanisms of PCS and subgroups of people at risk of long-term frailty.
*Important news
medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice/health-related behavior, or be treated as established information.