Prospective cohort study in the early stage of the COVID-19 pandemic, District of General Pueyrredón, Argentina (INECOVID): infection dynamics and risk factors

Abstract

Objective: to establish the magnitude and risk factors for SARS-CoV-2 infection in the District of General Pueyrredón, Buenos Aires, Argentina: the INECOVID study. Methodology: a prospective cohort was designed with participants from the District general population. The follow-up period was from June 22 to December 18, 2020, with a minimum appointment interval of 21 days. Data were obtained via questionnaires and serum or plasma samples. The primary event was considered as the time through seroconversion as evidence of SARS-CoV-2 infection. The accumulated risk of infection was estimated using the Kaplan Meier method. Cox models were built with time-dependent variables. Results: 345 participants were recruited (n = 222 women, 64.3%; 123 men, 35.7%), with a median age of 45 years in women (Interquartile range: 19) and 49 in men (Interquartile range: 26). 12.8% of participants (n = 44) had evidence of SARS-CoV-2 infection [incidence density of 9.1 cases (women: 11.1, men: 5.1) per 10,000 person-day]. 36.4% of the cases (n=16) were asymptomatic. The following factors were associated to the risk of infection: being a close contact of a confirmed COVID-19 case (HR=5,56; IC95% 2,85-10,83), being a health worker (HR=2,93; IC95% 1,55-5,52), living in crowded conditions (HR= 2,23; IC95% 1,13-4,49) and age (HR= 0,98; IC95% 0,95-1,00). Conclusion: the identified risk factors endorse the protection policies and protocols adopted by the Argentinian sanitary authorities for the general population and the care programs for health workers in the pre-vaccination phase.