An increase in the risk of clinical sequelae after SARS-CoV-2 infection

Scientists have observed that the general post-viral recovery time for patients suffering from viral diseases and severe respiratory coronavirus 2 (SARS-CoV-2) varies. Epidemiological studies have revealed morbidity among COVID-19 recovered patients is growing. During the acute phase of the infection, the pulmonary, hepatic, cardiovascular, cognitive, renal, and neurologic functions are often affected. Additionally, people who have already recovered from SARS-CoV-2 often complain of a wide-range of persisting symptoms that adversely affect the mental, social and physical well-being. However, researchers are yet to determine if these complications are related to the severity of the COVID-19 disease, as some individuals that have recovered from diseases such as pneumonia and influenza, also experience cerebrovascular, cardiovascular, and neurological complications.

Previous research associated with the longitudinal studies on patients who recovered from other coronavirus infections (MERS and SARS-CoV) revealed a common occurrence of prolonged physical and mental sequela. To date, the majority of studies have been targeted towards clinical sequelae among hospitalized patients, i.e., a small sample size. Owing to this limitation, the outcome of these results cannot be generalized for a larger population affected by COVID-19.

Not much work has been done regarding the prevalence of clinical sequelae, during the COVID-19 post-acute phase of infection, for the age group between 18 and 65 years. This age group is also considered to be at a lower risk of severe SARS-CoV-2 infection. Further, the role of gender, age, hospitalization, and pre-existing conditions, in increasing the risk of clinical sequelae in the post-acute phase of illness has not been explored much.

A new piece of research, published on the medRxiv* preprint server, focused on the role of factors such as gender, age, hospitalization, etc., in understanding the risks of clinical sequelae in the post-acute phase of COVID-19, in adults aged between 18 and 65 years. This study analyzed a larger dataset that included commercially insured adults in the United States, utilizing International Classification of Diseases Tenth Revision (ICD-10) codes. The analysis helped detect rare diseases and also determined if there was an association between subgroups.

In this study, researchers conducted a retrospective cohort analysis using three datasets obtained from the UnitedHealth Group Clinical Discovery Database. They studied the administrative data of outpatient and inpatient claims and analyzed the laboratory results for outpatients' SARS-CoV-2. They also included the hospital admission database which is regularly updated for patients with a primary, secondary, or tertiary diagnosis of COVID-19.

The current study has reported that 14% of individuals who are less than 65 years of age and were diagnosed with COVID-19 disease developed a minimum of one new clinical sequela that required immediate medical care during the post-acute stage of SARS-CoV-2 infection.  This research has confirmed the increased risks associated with specific types of sequelae, which occur up to 4 months after the start of the post-acute phase. In general, researchers have pointed out that risks increase with age, pre-existing health complications, and hospital admission due to COVID-19. However, this study reveals that even younger adults (≤50 years), individuals without pre-existing health conditions, and asymptomatic SARS-CoV-2 patients are also at risk of developing new clinical sequelae in the post-acute phase.

The research has also revealed the possibility of the development of clinical sequelae associated with mental health issues. For example, researchers have observed an increase in the level of anxiety, irrespective of one's age or pre-existing conditions. Thereby, concerning the possibility of health complications owing to SARS-CoV-2 infection, the chance of numerous clinical sequelae remains high during the post-acute phase.

During the post-acute phase of COVID-19, patients may develop several diseases such as chronic respiratory failure, cardiac irregularities such as tachycardia and hypercoagulability in the form of pulmonary embolism. Apart from these, there is a high possibility of the development of amnesia, anxiety, encephalopathy, diabetes, peripheral neuropathy, liver conditions, myocarditis, and fatigue. The current study is the first report that quantified the possibilities of health risks among the younger age group affected by COVID-19.

One limitation of this study is that it did not consider race and ethnicity at the individual level. Therefore, more research is required to understand the influence of ethnicity and race on the risk of long-term clinical sequelae. Another limitation of the study is related to several misclassifications, such as consideration of clinical diagnoses and comorbidities in previous years, resulting in biased data. However, the scientists believe that this research's outcome has provided clinicians a broad understanding of the possible risks among younger individuals during the post-acute phase of SARS-CoV-2.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Dr. Priyom Bose

Written by

Dr. Priyom Bose

Priyom holds a Ph.D. in Plant Biology and Biotechnology from the University of Madras, India. She is an active researcher and an experienced science writer. Priyom has also co-authored several original research articles that have been published in reputed peer-reviewed journals. She is also an avid reader and an amateur photographer.


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