Demographic and socioeconomic characteristics associated with SARS-CoV-2 reinfection: An observational study

Since SARS-CoV-2 emergence, risk factors for reinfection have not been totally determined. In this cohort, we analyzed the monthly incidence and outcomes of COVID-19 reinfection and its association with variants of concern, demographic, and socioeconomic factors. An infection case was defined as a positive test for SARS-CoV-2 and reinfection as the presence of a new positive test after 90 days or more of the previous infection. From September 1, 2020, to December 31, 2022, a total of 12,051 cases of COVID-19 were analyzed: 11,129 had one infection, 890 had two infections, and 32 had three infections, yielding a reinfection rate of 7.6%. Female sex was a risk factor for reinfection (RR 1.5, 95% CI 1.23-1.75). A higher risk of reinfection was related to not practicing hand hygiene (RR 1.35, 95% CI 1.14-1.60) and working on-site or from home compared with no work (RR 1.53, 95% CI 1.24-1.87 and RR 3.18, 95% CI 2.02-4.99, respectively). The risk of progressing to moderate or severe disease was higher during the first infection compared with the second (RR 2.12, 95% CI 1.34-3.34). Patients with two or three infections were older than those with one, with a mean age of 75.5 ± 17.3 and 59.6 ± 19.1 years old, respectively (p < 0.002). Our results underscore the importance of targeted public health campaigns and preventive measures for specific demographic groups.