Background & objectives: Population-based seroepidemiological studies measure the extent of SARS-CoV-2 infection in a country. We report the findings of the first round of a national serosurvey, conducted to estimate the seroprevalence of SARS-CoV-2 infection among adult population of India. Methods: From May 11 to June 4, 2020, a randomly sampled, community-based survey was conducted in 700 villages/wards, selected from the 70 districts of the 21 States of India, categorized into four strata based on the incidence of reported COVID-19 cases. Four hundred adults per district were enrolled from 10 clusters with one adult per household. Serum samples were tested for IgG antibodies using COVID Kavach ELISA kit. All positive serum samples were re-tested using Euroimmun SARS-CoV-2 ELISA. Adjusting for survey design and serial test performance, weighted seroprevalence, number of infections, infection to case ratio (ICR) and infection fatality ratio (IFR) were calculated. Logistic regression was used to determine the factors associated with IgG positivity. Results: Total of 30,283 households were visited and 28,000 individuals were enrolled. Population-weighted seroprevalence after adjusting for test performance was 0.73 per cent [95% confidence interval (CI): 0.34-1.13]. Males, living in urban slums and occupation with high risk of exposure to potentially infected persons were associated with seropositivity. A cumulative 6,468,388 adult infections (95% CI: 3,829,029-11,199,423) were estimated in India by the early May. The overall ICR was between 81.6 (95% CI: 48.3-141.4) and 130.1 (95% CI: 77.0-225.2) with May 11 and May 3, 2020 as plausible reference points for reported cases. The IFR in the surveyed districts from high stratum, where death reporting was more robust, was 11.72 (95% CI: 7.21-19.19) to 15.04 (9.26-24.62) per 10,000 adults, using May 24 and June 1, 2020 as plausible reference points for reported deaths. Interpretation & conclusions: Seroprevalence of SARS-CoV-2 was low among the adult population in India around the beginning of May 2020. Further national and local serosurveys are recommended to better inform the public health strategy for containment and mitigation of the epidemic in various parts of the country.

Summary Objectives  Visceral leishmaniasis (VL) is a major public health problem in Bihar, India. Unfortunately, accurate data on the incidence or prevalence of the disease are not available. This longitudinal study was undertaken to determine the incidence of VL in a Community Development Block area of the state of Bihar. Survey results were compared with official reports of the disease to assess the extent of underreporting by the Government health system. Methods  Three health subcentre areas in Kanti Block, consisting of 14 villages with a total population of 26 444, were selected. Active surveillance was performed every month from January 2001 to December 2003 by house to house survey to detect cases of fever for more than 15 days. Patients clinically suspected of suffering from VL were subjected to parasitological examination for confirmation. Analysis of records of the reporting agencies in the district was undertaken to compare and assess the extent of underreporting. Results  A total of 202 cases of VL were identified in 3 years giving an average annual incidence rate of 2.49/1000 population (95% CI = 2.15–2.83). As identification data of patients was not available with the official reporting agencies for 2001 and 2002, extent of underreporting could be assessed for 2003 only. In the study population, 65 cases of VL were detected during 2003 providing an annual incidence rate of 2.36/1000 population. Only eight (12.30%) cases were reported officially, resulting in underreporting by a factor of 8.13. In 2003, the official incidence rate of VL for Kanti Block was 0.31/1000 against the actual rate of 2.36/1000. As the constraints for official reporting at the block and the district levels are similar, the underreporting at district level was also assumed to be similar. This finding has significance in the preparation for elimination programme.

Background The first national severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurvey in India, done in May-June, 2020, among adults aged 18 years or older from 21 states, found a SARS-CoV-2 IgG antibody seroprevalence of 0•73% (95% CI 0•34-1•13). We aimed to assess the more recent nationwide seroprevalence in the general population in India. MethodsWe did a second household serosurvey among individuals aged 10 years or older in the same 700 villages or wards within 70 districts in India that were included in the first serosurvey. Individuals aged younger than 10 years and households that did not respond at the time of survey were excluded. Participants were interviewed to collect information on sociodemographics, symptoms suggestive of COVID-19, exposure history to laboratoryconfirmed COVID-19 cases, and history of COVID-19 illness. 3-5 mL of venous blood was collected from each participant and blood samples were tested using the Abbott SARS-CoV-2 IgG assay. Seroprevalence was estimated after applying the sampling weights and adjusting for clustering and assay characteristics. We randomly selected one adult serum sample from each household to compare the seroprevalence among adults between the two serosurveys.Findings Between Aug 18 and Sept 20, 2020, we enrolled and collected serum samples from 29 082 individuals from 15 613 households. The weighted and adjusted seroprevalence of SARS-CoV-2 IgG antibodies in individuals aged 10 years or older was 6•6% (95% CI 5•8-7•4). Among 15 084 randomly selected adults (one per household), the weighted and adjusted seroprevalence was 7•1% (6•2-8•2). Seroprevalence was similar across age groups, sexes, and occupations. Seroprevalence was highest in urban slum areas followed by urban non-slum and rural areas. We estimated a cumulative 74•3 million infections in the country by Aug 18, 2020, with 26-32 infections for every reported COVID-19 case.Interpretation Approximately one in 15 individuals aged 10 years or older in India had SARS-CoV-2 infection by Aug 18, 2020. The adult seroprevalence increased approximately tenfold between May and August, 2020. Lower infection-to-case ratio in August than in May reflects a substantial increase in testing across the country.

Background Earlier serosurveys in India revealed SARS-CoV-2 seroprevalence of 0.73% during May-June and 7.1% during August-September 2020. We conducted the third serosurvey during Dec 2020 and Jan 2021, to estimate the seroprevalence of SARS-CoV-2 infection among general population and healthcare workers (HCWs) in India. Methods We conducted the serosurvey in the same 70 districts selected for the first and second serosurveys. From each district, we enrolled at least 400 individuals aged ≥ 10 years from general population and 100 HCWs from sub-district level health facilities. Sera from general population were tested for presence of IgG antibodies against nucleocapsid (N) and spike protein (S1-RBD) of SARS-CoV-2, whereas sera from HCWs were tested for anti-S1-RBD. We estimated weighted seroprevalence adjusted for assay characteristics. Results Of the 28,598 sera from general population, 4585 (16%) had IgG antibodies against N, 6647 (23.2%) against S1-RBD and 7436 (26%) against either. The weighted and assay characteristic adjusted seroprevalence against either of the antibodies was 24.1 (95%CI: 23.0%-25.3%). Among 7385 HCWs, the seroprevalence of anti-S1-RBD IgG antibodies was 25.6% (95% CI: 23.5%-27.8%). Conclusions Nearly one in four individuals aged > = 10 years from general population as well as HCWs in India were exposed to SARS-CoV-2 by December 2020.

The Indian Government aspires to eliminate Kala-azar by 2010. Success of any disease control program depends on community participation, and there is no published data about the knowledge, attitude, and practices of the community about Kala-azar in endemic regions of India. For this knowledge, attitude, and practices (KAP) study, the heads of 3,968 households in a rural area, consisting of 26,444 populations, were interviewed using a pre-tested, semi-structured schedule. Most of the study subjects (97.4%) were aware of Kala-azar. Fever (71.3%) and weight loss (30.5%) were the most commonly known symptoms. The infectious nature of the disease was known to 39.9%. The majority believed that the disease spreads by mosquito bites (72.8%). For 63.6%, the breeding site of the vector was garbage collection. Only 23.6% preferred the public health sector for treatment, and 55.9% believed that facilities at primary health centers are not adequate. Poor knowledge of the study subjects about the disease and breeding sites of the vector underscores the need for health educational campaigns if the elimination program is to succeed.

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Background & objectives: India has been reporting the cases of coronavirus disease 2019 (COVID-19) since January 30, 2020. The Indian Council of Medical Research (ICMR) formulated and established laboratory surveillance for COVID-19. In this study, an analysis of the surveillance data was done to describe the testing performance and descriptive epidemiology of COVID-19 cases by time, place and person. Methods: The data were extracted from January 22 to April 30, 2020. The frequencies of testing performance were described over time and by place. We described cases by time (epidemic curve by date of specimen collection; seven-day moving average), place (area map) and person (attack rate by age, sex and contact status), and trends were represented along with public health measures and events. Results: Between January 22 and April 30, 2020, a total of 1,021,518 individuals were tested for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Testing increased from about 250 individuals per day in the beginning of March to 50,000 specimens per day by the end of April 2020. Overall, 40,184 (3.9%) tests were reported positive. The proportion of positive cases was highest among symptomatic and asymptomatic contacts, 2-3-fold higher than among those with severe acute respiratory infection, or those with an international travel history or healthcare workers. The attack rate (per million) by age was highest among those aged 50-69 yr (63.3) and was lowest among those under 10 yr (6.1). The attack rate was higher among males (41.6) than females (24.3). The secondary attack rate was 6.0 per cent. Overall, 99.0 per cent of 736 districts reported testing and 71.1 per cent reported COVID-19 cases. Interpretation & conclusions: The coverage and frequency of ICMR's laboratory surveillance for SARS-CoV-2 improved over time. COVID-19 was reported from most parts of India, and the attack rate was more among men and the elderly and common among close contacts. Analysis of the data indicates that for further insight, additional surveillance tools and strategies at the national and sub-national levels are needed.

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