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Journal ArticleDOI

Prevalence of SARS-CoV-2 infection in India: Findings from the national serosurvey, May-June 2020

01 Jan 2020-Indian Journal of Medical Research (Medknow Publications)-Vol. 152, Iss: 1, pp 48-60
TL;DR: Seroprevalence of SARS-CoV-2 was low among the adult population in India around the beginning of May 2020, and males, living in urban slums and occupation with high risk of exposure to potentially infected persons were associated with seropositivity.
Abstract: 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.
Citations
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10 Mar 2020

2,024 citations

Journal ArticleDOI
TL;DR: In this article, a systematic review and meta-analysis of serological surveys for antibodies to SARS-CoV-2 have been reported worldwide, and the authors aimed to synthesise, combine, and assess this large corpus of data.

174 citations

Journal ArticleDOI
14 Oct 2021-Science
TL;DR: In this paper, a Bayesian model explains the growth advantage of Delta through a combination of increased transmissibility and reduced sensitivity to immune responses generated against earlier variants (median estimates; ×1.5-fold, 20% reduction).
Abstract: Delhi, the national capital of India, has experienced multiple SARS-CoV-2 outbreaks in 2020 and reached population seropositivity of over 50% by 2021. During April 2021, the city became overwhelmed by COVID-19 cases and fatalities, as a new variant B.1.617.2 (Delta) replaced B.1.1.7 (Alpha). A Bayesian model explains the growth advantage of Delta through a combination of increased transmissibility and reduced sensitivity to immune responses generated against earlier variants (median estimates; ×1.5-fold, 20% reduction). Seropositivity of an employee and family cohort increased from 42% to 87.5% between March and July 2021, with 27% reinfections, as judged by increased antibody concentration after a previous decline. The likely high transmissibility and partial evasion of immunity by the Delta variant contributed to an overwhelming surge in Delhi.

165 citations

Journal ArticleDOI
Manoj V Murhekar1, Tarun Bhatnagar1, Sriram Selvaraju1, V. Saravanakumar1, Jeromie Wesley Vivian Thangaraj1, Naman Shah1, Muthusamy Santhosh Kumar1, Kiran Rade, R. Sabarinathan1, Smita Asthana1, Rakesh Balachandar2, Sampada Dipak Bangar1, Avi Kumar Bansal1, Jyothi Bhat1, Vishal Chopra, Dasarathi Das3, Alok Kumar Deb1, Kangjam Rekha Devi3, Gaurav Raj Dwivedi3, S. Muhammad Salim Khan4, C. P. Girish Kumar1, M. Sunil Kumar, Avula Laxmaiah5, Major Madhukar6, Amarendra Mahapatra3, Suman Sundar Mohanty1, Chethana Rangaraju7, Alka Turuk1, Dinesh Kumar Baradwaj5, Ashrafjit S. Chahal, Falguni Debnath1, Inaamul Haq4, Arshad Kalliath, Srikanta Kanungo3, Jaya Singh Kshatri3, G G J Naga Lakshmi, Anindya Mitra, A.R. Nirmala8, Ganta Venkata Prasad, Mariya Amin Qurieshi4, Seema Sahay1, Ramesh Kumar Sangwan1, Krithikaa Sekar1, Vijay K. Shukla, Prashant Singh1, Pushpendra Singh1, Rajeev K. Singh3, Dantuluri Sheethal Varma, Ankit Viramgami2, Samiran Panda1, D C S Reddy, Balram Bhargava1, Rushikesh Andhalkar, Anshuman Chaudhury, Hirawati Deval, Sarang Dhatrak, Rajeev Gupta, Ezhilarasan Ilayaperumal, Babu Jagjeevan, Ramesh Chandra Jha, K Kiran, Nivethitha N Krishnan, Alok Kumar, VG Vinoth Kumar, K. Nagbhushanam, Arlappa Nimmathota, Ashok Kumar Pandey, Harpreet Singh Pawar, Kushal Singh Rathore, Aby Robinson, Hari Bhan Singh, Vimith Cheruvathoor Wilson, Ashwini Yadav, Rajiv Yadav, T Karunakaran, Josephine Pradhan, T Sivakumar, Annamma Jose, K Kalaiyarasi, Sauvik Dasgupta, R Anusha, Tanu Anand, Giridhara R Babu, Himanshu Chauhan, Tanzin Dikid, Raman R. Gangakhedkar1, Shashi Kant, Sanket Kulkarni, J P Muliyil, Ravindra Mohan Pandey, Swarup Sarkar, Aakash Shrivastava, Sujeet Kumar Singh, Sanjay Zodpey, Aparup Das, Pradeep Das, Shanta Dutta, Rajni Kant, Kanwar Narain, Somashekar Narasimhaiah, Sanghamitra Pati, Shripad A. Patil, Hemalatha Rajkumar, Tekumalla Ramarao, Kamalesh Sarkar, Shalini Singh, Gurudayal S Toteja, Kamran Zaman 
TL;DR: 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 sero-survey was conducted in this article.

143 citations

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the risk of SARS-CoV-2 re-infections in the general population in Austria by tracking polymerase chain reaction (PCR)-confirmed infections of both groups during the second wave from September 1 to November 30, 2020.
Abstract: Background A key question concerning coronavirus disease 2019 (COVID-19) is how effective and long lasting immunity against this disease is in individuals who were previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to evaluate the risk of SARS-CoV-2 re-infections in the general population in Austria. Methods This is a retrospective observational study using national SARS-CoV-2 infection data from the Austrian epidemiological reporting system. As the primary outcome, we aim to compare the odds of SARS-CoV-2 re-infections of COVID-19 survivors of the first wave (February to April 30, 2020) versus the odds of first infections in the remainder general population by tracking polymerase chain reaction (PCR)-confirmed infections of both groups during the second wave from September 1 to November 30, 2020. Re-infection counts are tentative, since it cannot be excluded that the positive PCR in the first and/or second wave might have been a false positive. Results We recorded 40 tentative re-infections in 14 840 COVID-19 survivors of the first wave (0.27%) and 253 581 infections in 8 885 640 individuals of the remaining general population (2.85%) translating into an odds ratio (95% confidence interval) of 0.09 (0.07 to 0.13). Conclusions We observed a relatively low re-infection rate of SARS-CoV-2 in Austria. Protection against SARS-CoV-2 after natural infection is comparable with the highest available estimates on vaccine efficacies. Further well-designed research on this issue is urgently needed for improving evidence-based decisions on public health measures and vaccination strategies.

106 citations

References
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Journal ArticleDOI
TL;DR: It is suggested that SARS-CoV2-specific IgG or IgM seroconversion occurs within 20 days post symptom onset and may be helpful for the diagnosis of suspected patients with negative RT–PCR results and for the identification of asymptomatic infections.
Abstract: We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.

2,473 citations

10 Mar 2020

2,024 citations


"Prevalence of SARS-CoV-2 infection ..." refers background in this paper

  • ...Based on the overall adjusted seroprevalence of 0.73 per cent and reported number of COVID-19 cases, it was estimated that for every RT-qPCR confirmed case of COVID-19, there were 82-130 infections in India....

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  • ...The seroprevalence of 0.73 per cent was estimated assuming that the two tests are completely independent....

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Journal ArticleDOI
Marina Pollán1, Beatriz Pérez-Gómez1, Roberto Pastor-Barriuso1, Jesús Oteo1, Miguel A. Hernán2, Miguel A. Hernán3, Mayte Pérez-Olmeda1, Jose L Sanmartín, Aurora Fernández-García1, Aurora Fernández-García4, Israel Cruz1, Nerea Fernández de Larrea1, Marta Molina, Francisco Rodríguez-Cabrera1, Mariano Martín, Paloma Merino-Amador4, Jose León Paniagua1, Juan F Muñoz-Montalvo, Faustino Blanco, Raquel Yotti1, Rodrigo Gutiérrez Fernández, Saturnino Mezcua Navarro, Matías Salinero Hernández, Manuel Cuenca-Estrella, Pablo Fernández-Navarro, Ana Avellón, Giovanni Fedele, Jesús Oteo Iglesias, María Teresa Pérez Olmeda, Maria Elena Martinez, Francisco D. Rodríguez-Cabrera1, Susana Padrones Fernández, José Manuel Rumbao Aguirre, José M. Navarro Marí, Begoña Palop Borrás, Ana Belén Pérez Jiménez, Manuel Rodríguez-Iglesias, Ana María Calvo Gascón, María Luz Lou Alcaine, Ignacio Donate Suárez, Oscar Suárez Álvarez, Mercedes Rodríguez Pérez, Margarita Cases Sanchís, Carlos Javier Villafáfila Gomila, Lluis Carbo Saladrigas, Adoración Hurtado Fernández, Antonio Oliver, Elías Castro Feliciano, María Noemí González Quintana, José María Barrasa Fernández, María Araceli Hernández Betancor, Melisa Hernández Febles, Leopoldo Martín Martín, Luis-Mariano López López, Teresa Ugarte Miota, Inés De Benito Población, María Sagrario Celada Pérez, María Natalia Vallés Fernández, Tomás Maté Enríquez, Miguel Villa Arranz, Marta Domínguez-Gil González, Isabel Fernández-Natal, Gregoria Megías Lobón, Juan Luis Muñoz Bellido, Pilar Ciruela, Ariadna Mas i Casals, Maria Doladé Botías, M. Angeles Marcos Maeso, Dúnia Pérez del Campo, Antonio Félix de Castro, Ramón Limón Ramírez, Maria Francisca Elías Retamosa, Manuela Rubio González, María Sinda Blanco Lobeiras, Alberto Fuentes Losada, Antonio Aguilera, Germán Bou, Yolanda Caro, Noemí Marauri, Luis Miguel Soria Blanco, Isabel González, Montserrat Hernández Pascual, Roberto Alonso Fernández, Natalia Cabrera Castro, Aurora Tomás Lizcano, Cristóbal Ramírez Almagro, M. Hernández, Nieves Ascunce Elizaga, María Ederra Sanz, Carmen Ezpeleta Baquedano, Ana Bustinduy Bascaran, Susana Iglesias Tamayo, Luis Elorduy Otazua, Rebeca Benarroch Benarroch, Jesús Lopera Flores, Antonia Vázquez de la Villa 
TL;DR: In this paper, a nationwide population-based study aims to estimate the seroprevalence of SARS-CoV-2 infection in Spain at national and regional level.

1,435 citations

18 Aug 2020
TL;DR: The majority of the Spanish population is seronegative to SARS-CoV-2 infection, even in hotspot areas, and results emphasise the need for maintaining public health measures to avoid a new epidemic wave.

749 citations

Journal ArticleDOI
TL;DR: This paper reviews basic methods for examining the sensitivity of study results to biases, with a focus on methods that can be implemented without computer programming.
Abstract: Despite the importance of systematic errors and biases, quantitative methods that take account of these biases have seen much less development than methods for addressing random error. There are at least two reasons for this. First, until recently, randomized experiments supplied most of the impetus for statistical developments. These experiments were concentrated in agriculture, manufacturing, and clinical medicine, and often could be designed in such a way that systematic errors played little role in the final results. The second reason for the limited development of methods for addressing bias is more fundamental: Most biases can be fully analysed only if certain additional 'validation' data are available, but such data are not usually collected and are often very limited when they are available. As a result, investigators must resort to less satisfactory partial analyses, or eschew any quantitative assessment of bias. Quantitative assessments of bias can provide valuable insight into the importance of various sources of error, and can help one better assess the uncertainty of study results. Such assessments may demonstrate that certain sources of bias cannot plausibly explain a study result, or that a bias explanation cannot be ruled out. I here review some basic methods for such assessment. Because methods for bias assessment are not available

526 citations

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