Post-COVID symptoms prevalence, latent class pattern, and functional impact: A population-based cross-sectional study in two Chilean cities, 2024.

INTRODUCTION: Post-COVID-19 condition affects approximately 6% of individuals globally. Most evidence is based on hospitalized patients and is from countries with relatively low vaccination coverage. This study estimates the prevalence of symptoms compatible with post-COVID-19 and explores symptom patterns in a population-based sample from Chile, a country with high vaccination coverage. Moreover, it examines their associations with daily activities and demographic, social, and clinical factors. METHODS: A cross-sectional study was conducted in May 2024 in two Chilean Cities, involving 654 participants (88.5% response rate) aged ≥ seven years, from randomly selected households. Ten post-COVID-19 symptoms that persisted for ≥ three months were collected. Latent class analysis identified symptom patterns. RESULTS: Among 277 participants with a confirmed COVID-19 diagnosis, 114 reported at least one symptom lasting ≥ 3 months. Population-weighted prevalence of at least one post-COVID-19 symptom was 17.4% in the general population and 40.7% among individuals with prior COVID-19. Among those with post-COVID-19 symptoms, 40.1% reported a reduction in daily activities. Three classes were explored: class 1 (38.4%) characterized by fatigue, ageusia/anosmia, and muscular/joint pain; class 2 (40.7%) with predominant cardiorespiratory symptoms; and class 3 (20.9%) with multisystemic symptoms. Class three was associated with a higher frequency of comorbidities (particularly diabetes), hospitalization, multiple COVID-19 episodes, and Aboriginal affiliation. Classes 2 and 3 were independently associated with younger age and diabetes, class 2 was additionally associated with lower educational attainment and lower BMI, while class 3 was additionally associated with Aboriginal affiliation. CONCLUSIONS: This population-based study reveals a substantial burden of at least one post-COVID-19 symptom, with distinct symptom classes highlighting the need for tailored interventions. These findings underscore the importance of targeted public health policies and personalized clinical approaches, particularly for severe symptom classes that impact quality of life and contribute critical data from Latin America to the global understanding of post-COVID-19 condition.