High seroprevalence after the second wave of SARS-COV2 respiratory infection in a small settlement on the northern coastal of Peru
Authors: Toledo Angie K. , León-Jimenez Franco , Cavalcanti Sofia , Vilchez-Barreto Percy , Reto Narcisa , Vega Jessica , Bolivar Lucia M , Rhor Matilde , Ypanaque Jhon , Silva Henry , Moyano Luz M. ,   Group of Neuroepidemiology and Science of Life of Peru
Published: July 2023

Background

Due to more infections from variations that could escape vaccination and immunity by asymptomatic to uninfected transmission, COVID-19’s second wave had higher seroprevalence globally. Public health constraints and herd immunity may not work against these novel variations’ infectivity. This population-based study in Peru’s Tumbes Region during the second wave of COVID-19 seeks to determine seroprevalence and demographic changes from the first wave.

Methodology/Principal findings

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. 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/Significance

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.

Author summary

In Peru, the healthcare system was overwhelmed by the COVID-19 pandemic due to the lack of hospital capacity, oxygen supply, political unrest, and a fragmented healthcare system. During the first wave, the prevalence ranged from 20.8% to 72%, and it was predicted that the second wave would be disastrous. To assess the seroprevalence of SARS-CoV-2, a cross-sectional study was conducted in the settlement “AAHH Las Flores” located in front of Tumbes National University’s main campus. A door-to-door intervention was conducted, and a total of 580/781 (74.26%) individuals over than 2 years and above agreed to participate. After adjusting for sensitivity and specificity, the calculated adjusted seroprevalence was 50.15%. Women had a slightly higher adjusted seroprevalence compared to men, and the age groups with the highest prevalence of IgG seropositive were from 12 to 17 years, from 30 to 59 years, and older than 60 years. More than 80% of seropositive patients were asymptomatic in all age groups. The study’s findings suggest that COVID-19 transmission in the settlement was higher during the second wave, and asymptomatic individuals could have played a critical role in spreading the virus.