SARS‐CoV‐2 infections in households in a peri‐urban community of Lima, Peru: A prospective cohort study

Background We assessed the prevalence and incidence of SARS‐CoV‐2 infections in a prospective study of households in Lima, Peru. Methods Households with a child, a young adult 18–50 years, and an adult age >50 years in peri‐urban Lima were followed with twice‐a‐week household visits during a 2‐month period. Nasal swabs and saliva specimens were collected twice weekly, and nasopharyngeal swabs were collected weekly from each participant, regardless of symptoms. Laboratory‐confirmed SARS‐CoV‐2 infection was defined by two RT‐PCR tests from any of the collected specimens within a week. Blood samples collected at enrollment and end of follow‐up were tested with rapid serological tests. We calculated the prevalence and incidence of laboratory‐confirmed SARS‐CoV‐2 infections. Results We enrolled 132 participants from 44 households: 44 children, 44 young adults, and 44 older adults. A total of 13 SARS‐CoV‐2 infections were detected in eight households, for an overall period prevalence of 9.85% (95% confidence interval [CI]: 5.35–16.25). Most (61.54%) infections were symptomatic. Eight of 11 (72.73%) SARS‐CoV‐2 detections corresponded to the Lambda variant. During 218.79 person‐months at risk of follow‐up, there were six new SARS‐CoV‐2 infections detected (2.74 per 100 person‐month, 95% CI: 1.25–6.04). At enrollment, 59 of 128 participants tested had positive SARS‐CoV‐2 IgG serology (46.09%, 95% CI: 37.25–55.12). Five of six new infections occurred among participants with negative baseline serology. Conclusions We demonstrated high incidence of SARS‐CoV‐2 infections in households, especially among subjects without evidence of prior infection, most of them not detected by the Ministry of Health system.