High seroprevalence after the second wave of SARS-COV2 respiratory infection in a small settlement on the northern coastal of Peru.

Objective: determine seroprevalence and demographic changes from the first wave. Material and Methodology: In Dec 2021-Jan 2022, a study in Tumbes' informal settlement sampled individuals over 2 years old from one in every four households. Finger-prick blood samples and symptom surveys were collected. Results: On the second wave, there was a substantial rise in adjusted seroprevalence (50.15%, 95% CI [45.92 – 54.40]) compared with the first wave (24.82 %, 95%CI [22.49 – 27.25]), with females maintaining a higher seroprevalence (53.89; 95% CI [48.48-59.23]) vs. 45.49; 95% CI [38.98-52.12], p=0.042) compare to males. Those under 18 years of age had the highest IgG seropositivity: the 12–17 age group during the second wave (85.14%) and the 2–11 age group (25.25%) during the first wave. Nasal congestion and cough were symptoms associated with seropositivity, unlike the first wave. Conclusions: In Tumbes, the seroprevalence of COVID-19 increased by twofold compared to the initial wave. Inadequate infrastructure and limitations in human resources and supplies in healthcare facilities made the Peruvian health system collapse. We must include in epidemiological surveillance mHealth tools that enable real-time reporting of new cases. Working alongside the community is the only way to improve any new intervention strategy to prevent or control a new pandemic.