We describe the epidemiological characteristics and associated risk factors of those presenting at a large testing centre for SARS-CoV-2 infection. This is a retrospective record review of individuals who underwent SARS-CoV-2 testing by reverse transcription–polymerase chain reaction (RT-PCR) at a high-throughput national-level government facility located in the north of India. Samples collected from 6 April to 31 December 2020 are included in this work and represent four highly populous regions. Additionally, there was a prospective follow-up of 1729 cases through telephone interviews from 25 May 2020 to 20 June 2020. Descriptive analysis has been performed for profiling clinic-epidemiological aspects of suspect cases. Multivariable logistic regression analysis was undertaken to determine risk factors that are associated with SARS-CoV-2 test positivity and symptom status. A total of 125 600 participants' details have been included in this report. The mean (s.d.) age of the participants was 33.1 (±15.3) years and 66% were male. Among these tested, 9515 (7.6%) were positive for COVID-19. A large proportion of positive cases were asymptomatic. In symptomatic positive cases, the commonest symptoms were cough and fever. Increasing age (groups 20–59 and ≥60 years compared to age group less than 5 years), male sex, history of international travel, symptoms for SARS-CoV-2, and participants from Delhi and Madhya Pradesh were positively associated with SARS-CoV-2 test positivity. Having co-morbidity, risk behaviours and intra-familial positivity were associated with a positive odds ratio for exhibiting SARS-CoV-2 symptoms. Intensified testing and isolation of cases, identification of both asymptomatic and symptomatic individuals and additional care of those with co-morbidities and risk behaviours will all be collectively important for disease containment in India. Reasons for differentials in testing between men and women remain an important area for in-depth study. The increased deployment of vaccines is likely to impact the trajectory of COVID-19 in the coming time, and therefore our data will serve as a comparative resource as India experiences the second wave of infection in light of newer variants that are likely to accelerate disease spread.

我们描述了在大型 SARS-CoV-2 感染检测中心就诊者的流行病学特征和相关危险因素。这是对在位于印度北部的高通量国家级政府设施中通过逆转录聚合酶链反应 (RT-PCR) 进行 SARS-CoV-2 检测的个人的回顾性记录审查。这项工作包括从 2020 年 4 月 6 日至 12 月 31 日收集的样本，代表四个人口稠密的地区。此外，在 2020 年 5 月 25 日至 2020 年 6 月 20 日期间，通过电话采访对 1729 例病例进行了前瞻性随访。对疑似病例的临床流行病学方面进行了描述性分析。进行多变量逻辑回归分析以确定与 SARS-CoV-2 检测阳性和症状状态相关的风险因素。本报告共收录了 125 600 名参与者的详细信息。参与者的平均 (sd) 年龄为 33.1 (±15.3) 岁，66% 为男性。在这些测试中，9515 (7.6%) 对 COVID-19 呈阳性。很大一部分阳性病例是无症状的。在有症状的阳性病例中，最常见的症状是咳嗽和发烧。年龄增加（20-59 岁和 60 岁以上与 5 岁以下年龄组相比）、男性、国际旅行史、SARS-CoV-2 症状以及来自德里和中央邦的参与者与 SARS- CoV-2 检测呈阳性。有合并症，风险行为和家族内阳性与表现出 SARS-CoV-2 症状的阳性比值比相关。加强检测和隔离病例、识别无症状和有症状的个体以及对有合并症和风险行为的人进行额外护理，对于印度的疾病控制都具有重要意义。男女测试差异的原因仍然是深入研究的重要领域。疫苗部署的增加可能会影响未来 COVID-19 的发展轨迹，因此我们的数据将作为比较资源，因为印度可能会加速疾病传播的新变种而经历第二波感染. 加强检测和隔离病例、识别无症状和有症状的个体以及对有合并症和危险行为的人进行额外护理，对于印度的疾病控制都具有重要意义。男女测试差异的原因仍然是深入研究的重要领域。疫苗部署的增加可能会影响未来 COVID-19 的发展轨迹，因此我们的数据将作为比较资源，因为印度可能会加速疾病传播的新变种而经历第二波感染. 加强检测和隔离病例、识别无症状和有症状的个体以及对有合并症和风险行为的人进行额外护理，对于印度的疾病控制都具有重要意义。男女测试差异的原因仍然是深入研究的重要领域。疫苗部署的增加可能会影响未来 COVID-19 的发展轨迹，因此我们的数据将作为比较资源，因为印度可能会加速疾病传播的新变种而经历第二波感染. 男女测试差异的原因仍然是深入研究的重要领域。疫苗部署的增加可能会影响未来 COVID-19 的发展轨迹，因此我们的数据将作为比较资源，因为印度可能会加速疾病传播的新变种而经历第二波感染. 男女测试差异的原因仍然是深入研究的重要领域。疫苗部署的增加可能会影响未来 COVID-19 的发展轨迹，因此我们的数据将作为比较资源，因为印度可能会加速疾病传播的新变种而经历第二波感染.