The sensitivity and specificity of the test kit were 94.4% and 100% respectively [7]. time periods [1,2]. In India, the 1st wave was seen from March to November 2020. The second wave in the form of the delta variant, from March to June 2021, led to a massive surge of symptomatic COVID, hospitalization, and fatality [3]. There was a subsequent third wave of less virulent omicron Fluocinonide(Vanos) variant at the end of 2021. For almost 3 years India experienced this series of the pandemic waves, which experienced impact on populace health. India started the COVID-19 vaccination in January 2021; in the beginning for the health care workers, and frontline workers followed by the elderly populace, and finally for those adults [4]. India, as well as most parts of the world, has came into the phase of endemicity where a considerable proportion of the population is definitely positive for SARS-CoV-2 antibody [5]. Varying levels of seropositivity were found among the population of different claims of India. The seropositivity status of a populace shows the Fluocinonide(Vanos) degree of past illness, the indirect safety from subsequent illness, the proportion of the vulnerable populace, etc. Similarly, repeated serological screening tells about the Rabbit Polyclonal to Collagen III switch in the overall illness inside a community. There were very few studies in cohort design assessing the antibody kinetics for a longer duration. Consequently, we targeted to assess the switch in antibody prevalence and its kinetics inside a closed cohort over six months across the country in different sub-population in India. == Strategy == == Study Fluocinonide(Vanos) design == This was a population-based, multi-centric, age-stratified prospective cohort study under WHO (World Health Organisation) Unity protocols for the SARS-CoV-2 sero-surveillance [6]. A total of three rounds of follow-up were carried out for the same cohort of the study participants viz. at baseline, 3rdmonths, and 6thmonths. == Study setting and patient selection == The study was carried out at five selected study sites in India. The study sites were Delhi, Bhubaneswar, Gorakhpur, Pondicherry, and Agartala situated in the state of Delhi, Odisha, Uttar Pradesh, Pondicherry, and Tripura respectively. The study populace were from both the rural and urban areas of each site except in the Agartala site where the tribal populace was included in place of the urban populace. For Delhi site, an urban resettlement colony consisting mostly of a populace from low socio-economic strata in the south Delhi area was chosen to represent urban populace. The rural populace was selected from Ballabgarh block in the Faridabad area of nearby Haryana state. Faridabad district experienced contiguous border with Delhi state and arrived under Delhi National Capital Region (Delhi NCR). Ballabgarh block was the rural field practice area of the investigating site spread across 50 square kilometres with 28 villages having a populace of 102,000 as per 2021 data. The Bhubaneswar site in south-Eastern India included an urban area under the Bhubaneswar Municipal Corporation (BMC) and a rural area at selected villages of adjacent Khordha districts at a distance of 2540 kilometres from the site institute. Gorakhpur was a city situated Fluocinonide(Vanos) in Uttar Pradesh, a state in Northern India. The city was a major transit point of surface transport near the India-Nepal international border. The rural area was in the vicinity of the city with an average range of 1672 kilometres from the city centre whereas the urban area was in the centre of the city in a selected municipality block. In north-eastern India, the Agartala site was situated in the state of Tripura. This site included the rural and tribal populace from the selected villages situated at a distance of 1630 km from the city centre. In southern India, the Puducherry site was a Union Territory of an area of 20 square kilometres where selected municipality wards and villages were included for the urban and rural populace. == Sample size and sampling strategy == In each of Fluocinonide(Vanos) the study.
