A recent study published within the British Medical Journal evaluated long-term symptoms and outcomes related to post-coronavirus disease 2019 (COVID-19) condition.

Around 20% to 30% of non-vaccinated individuals suffer from the post-COVID-19 condition. Multiple studies investigating the long-term outcomes of the post-COVID-19 condition have reported that 22% to 75% of affected individuals experienced symptoms longer than one 12 months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Many such studies comprised specific populations, focused on certain dimensions of the condition, and didn’t include a prospective follow-up. Furthermore, their generalizability may very well be limited across the spectrum of COVID-19 severity. As such, limited knowledge and the dearth of consensus on the core consequence set of the post-COVID-19 condition have resulted in using different consequence measures in observational studies, impacting their comparability.

Study: Recovery and symptom trajectories as much as two years after SARS-CoV-2 infection: population based, longitudinal cohort study. Image Credit: p.sick.i / Shutterstock

In regards to the study

The current study comprehensively characterised the post-COVID-19 condition within the longitudinal population-based Zurich SARS-CoV-2 cohort. Adult residents of the Zurich canton, Switzerland, were eligible if they may follow study protocols. Subjects with a confirmed SARS-CoV-2 infection diagnosis between August 6, 2020, and January 19, 2021, were recruited. The comparator group included participants from one other study without SARS-CoV-2 infection.

Data obtained from questionnaires were used for evaluation. At baseline, the questionnaire captured data on sociodemographics, comorbidities, pre-infection health status, and acute infection. Follow-up questionnaires were administered at multiple time points after infection, which collected information on symptoms and mental and physical health.

The first consequence was the relative health status at 6, 12, 18, and 24 months post-infection. The consequence was defined using self-reported recovery status and overall health status. Secondary outcomes were the prevalence and severity of symptoms. Self-perceived severity was evaluated using a five-point Likert scale and stratified into mild, moderate, and severe categories. Further, the team assessed the trajectories of symptoms and relative health status between six and 24 months.

Additional scale-based assessments were used to research hostile outcomes, akin to fatigue, dyspnea, depression, anxiety, stress, and quality of life. Data after reinfection weren’t considered for evaluation. The purpose prevalence and severity of symptoms and the relative health status were descriptively evaluated at follow-up. The characteristics of participants with different trajectories were compared. The surplus risk of symptoms and hostile outcomes was assessed at six months.

Findings

Overall, 1106 individuals participated within the Zurich SARS-CoV-2 cohort. Of those, 788 accomplished the assessment at 24 months, and 776 accomplished all questionnaires between six and 24 months. Most participants were symptomatic (86%) during acute COVID-19 and 4.3% required hospitalization. Around 51.2% of participants were females, and 55.2% returned to normal health status in lower than one month post-infection. Nonetheless, nearly 23% of participants didn’t recuperate by six months post-infection.

Mild, moderate, and severe health impairment was observed in 16.2%, 3.6%, and a couple of.7% of participants, respectively. The proportion of participants reporting non-recovery declined over time and was 18.5% at 12 months and 17.2% at 24 months. Greater than 68% of participants reported continued recovery over time. By 24 months, 13.5% had improved or recovered, 5.2% had worsened health status, and 4.4% had stable health impairment. 

The prevalence of symptoms was similar at follow-up time points at around 51%. Nonetheless, the prevalence of COVID-19-related symptoms declined from about 29% at six months to 18.1% at 24 months. Notably, most participants with COVID-19-related symptoms reported non-recovery at 24 months. The common symptoms were fatigue, dyspnea, post-exertional malaise, poor concentration or memory, and altered smell or taste.

The proportion of participants with hostile outcomes on scale-based assessments increased shortly after the infection and decreased from one month onwards. By 24 months, the proportion of participants with fatigue, dyspnea, depression, anxiety, and stress was 36.8%, 23.4%, 12.5%, 11.7%, and seven%, respectively. The prevalence of any symptom was higher within the Zurich SARS-CoV-2 cohort in comparison with non-infected subjects within the comparator group.

The surplus risks amongst infected subjects relative to non-infected participants were the best for altered smell or taste, post-exertional malaise, reduced memory or concentration, dyspnea, and fatigue. Further, more infected participants had anxiety symptoms at six months than non-infected subjects. There have been no differences within the proportions of subjects with stress, depression, or other hostile outcomes.

Conclusions

In sum, around 18% of subjects infected with SARS-CoV-2 reported post-COVID-19 symptoms, and 17% didn’t attain their normal health status by 24 months after infection. Although many subjects recovered or improved over time, some had worsened health status or alternating courses. As well as, there was strong evidence that infected individuals had an excess risk of symptoms than non-infected subjects.