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

Abstract

To establish the magnitude and risk factors for SARS-CoV-2 infection in the General Pueyrredón, Buenos Aires, Argentina: the INECOVID study. Prospective cohort designed with participants from the District general population. The follow-up period was from June 22nd to December 18th, 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 to seroconversion (IgG) 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. 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 in close contact of a confirmed COVID-19 case (HR=5.56; 95%CI 2.85-10.83), being a health worker (HR=2.93; 95%CI 1.55-5.52), living in crowded conditions (HR=2.23; 95%CI 1.13-4.49), and age (HR=0.98; 95%CI 0.95-1.00). 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.