Clinical Spectrum and Outcomes of Post-COVID Syndrome Among Adults in Rural Kerala: A Cohort Study

Background Post-COVID syndrome (PCS) is a condition that affects some individuals who have recovered from COVID-19, characterized by persistent symptoms that last for weeks or months after the acute illness has resolved. Despite ongoing research on PCS, key gaps remain, including short follow-up, absence of control groups, small sample sizes, and limited representation of mild-to-moderate cases. Objectives The objective of this study is to determine the incidence proportion and outcomes of PCS over 12 months in a rural district of Kerala. Methods A prospective cohort study was conducted among 596 participants, of which 298 had a previous COVID-19 infection confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) or antigen test (exposure group), while the remaining had no evidence of COVID-19 (control group). Field workers collected data by direct interviews. Study variables, including blood pressure (BP), blood sugar, oxygen (O₂) saturation, and six-minute walk distance (6MWD), were recorded at six, nine, and 12 months following recruitment. Results The incidence proportion of PCS was 91.9% (95% CI: 88.8-95.0%) in the exposure cohort (i.e., 274/298) compared to 83.2% (95% CI: 79.0-87.4%) in the controls (i.e., 248/298) at six months. The differences in the incidence proportion of PCS between the groups were statistically significant. The differences in mean 6MWD at six, nine, and 12 months were statistically significant (p = 0.037), with a nadir at nine months. Mean systolic and diastolic BP were significantly higher in the exposure group than the control group at six and nine months, which converged by 12 months. Conclusion The persistence of symptoms and functional impairments was common among both the exposure and control groups, though more frequent in the exposure (COVID-19) group. The findings suggest that post-COVID morbidity may overlap with the background community symptom burden. Further, multicenter studies with serology and adjusted analyses are required to refine pathways for screening and long-term care.