Seroprevalence of COVID-19 infection in a rural district of South India: A population-based seroepidemiological study

Abstract

Objectives We aimed to estimate the seroprevalence of COVID-19 in a rural district of South India, six months after the index case. Methodology We conducted a cross-sectional study of 509 adults aged more than 18 years. From all the four subdistricts, two grampanchayats (administrative cluster of 5–8 villages) were randomly selected followed by one village through convenience. The participants were invited for the study to the community-based study kiosk set up in all the eight villages through village health committees. We collected socio-demographic characteristics and symptoms using a mobile application-based questionnaire, and we tested samples for the presence of IgG antibodies for SARS CoV-2 using an electro chemiluminescent immunoassay. We calculated age-gender adjusted and test performance adjusted seroprevalence. Results The age-and gender-adjusted seroprevalence was 8.5% (95% CI 6.9%- 10.8%). The unadjusted seroprevalence among participants with hypertension and diabetes was 16.3% (95% CI:9.2–25.8) and 10.7% (95% CI: 5.5–18.3) respectively. When we adjusted for the test performance, the seroprevalence was 6.1% (95% CI 4.02–8.17). The study estimated 7 (95% CI 1:4.5–1:9) undetected infected individuals for every RT-PCR confirmed case. Infection Fatality Rate (IFR) was calculated as 12.38 per 10000 infections as on 22 October 2020. History of self-reported symptoms and education were significantly associated with positive status (p < 0.05) Conclusion A significant proportion of the rural population in a district of south India remains susceptible to COVID-19. A higher proportion of susceptible, relatively higher IFR and a poor tertiary healthcare network stress the importance of sustaining the public health measures and promoting early access to the vaccine are crucial to preserving the health of this population. Low population density, good housing, adequate ventilation, limited urbanisation combined with public, private and local health leadership are critical components of curbing future respiratory pandemics.

A three-phase population based sero-epidemiological study: Assessing the trend in prevalence of SARS-CoV-2 during COVID-19 pandemic in Jordan

“…It is crucial to recognize an infected person at an early stage to cut the transmission of COVID-19, although in reality they do not often require medication attention or contribute to rapid spread of the infection. But it is not sufficient to rely only on confirmed cases of COVID-19 cases detected by polymerase chain reaction (PCR) for control measures, as these tests often rule out asymptomatic and pre-symptomatic cases [ 6 ]. In order to overcome this challenge, A quantitative, population-based sero-epidemiological survey can better determine the entity of the population exposed to SARS-CoV-2 by revealing the proportion of the population with antibodies against the virus, to generate data on immunity status of population and to implement containment measures accordingly.…”

Seroprevalence and Infection Attack Rate of COVID-19 in Indian Cities

“…A significant amount of the people infected with SARS-CoV-2 do not show symptoms, yet they transmit the disease to other susceptible populations (Long et al 2020;Oran and Topol 2021;Tu et al 2020). It has been reported that asymptomatic cases of COVID-19 could reach from 5% up to about 80% of all infections (Inbaraj, George, and Chandrasingh 2021;Yanes-Lane et al 2020), especially for young and healthy individuals. In slums settings like India, these estimates could reach up to more than 90% (George et al 2021;Velumani et al 2021).…”

“…Therefore, it is imperative to identify an infected individual at the early stage of the infection and trace all possible contacts in order to break the transmission paths, and also to prevent more rapid spread of the pandemic. However, recognizing an asymptomatically (and pre-symptomatic) infected individual is practically difficult (and sometimes impossible) since they don't seek medical attention, which helps to identify their exposure to the disease (Gao et al 2021;Inbaraj, George, and Chandrasingh 2021). As a result, relevant authorities, including the WHO, did not recommend absolute reliance on the morbidity and mortality cases identified through RT-PCR since it is very likely to have potential under-reporting issues (Inbaraj, George, and Chandrasingh 2021).…”

“…Serological survey data for 12 Indian cities were obtained from (Velumani et al 2021). A serological survey is usually carried out to investigate the prevalence of the size of an epidemic (population infected) in a given population by identifying the presence of specific antibodies used against the virus (Anand et al 2021;George et al 2021;Inbaraj, George, and Chandrasingh 2021;Velumani et al 2021).…”

Mega festivals like MahaKumbh, a largest mass congregation, facilitated the transmission of SARS-CoV-2 to humans and endangered animals via contaminated water

“…The likelihood of rapid virus dispersal throughout the crowd and subsequently (upon their return to villages and cities all over the Indian subcontinent) the country was very high. Amidst the ongoing MahaKumbh festival in April, an increase of nearly 89-fold in COVID-19 cases has been documented in Uttarakhand compared to February (the initial period of the festival) ( Upadhyay, 2021 ), with scores of transmissions that have not been picked up by clinical diagnostics ( Inbaraj et al, 2021 ). The number of confirmed positive cases that have been found among MahaKumbh returnees across the country (~0.4 million cases on May 8, 2021, a global record), clearly indicates to what immense extend congregated religious gathering has fuelled India's coronavirus outbreak and led to the spread of the pandemic into even remote villages ( Bhutta et al, 2021 ).…”