Madhavan Ramya, Paul Jackwin Sam, Babji Sudhir, Thamizh Isai, Kumar Dilesh, Khakha Shainey Alokit, Rennie Aarene, Kumar Keerthana, Dhanapal Pavithra, Saravanan Poornima, Kumar Ajith, Immanuel Sushil, Gandhi Vaishnavi, Kumar Anand, Babu Johnson John, Gangadharan Nandu Thrithamarassery, Jagadeesan Premkumar, John Elizabeth, Jamora Colin, Palakodeti Dasaradhi, Bhati Rubina, Thambidurai Saranya Devi, Suvatha Arati, George Anna, Kang Gagandeep, John Jacob
The Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Department of Community Health, Christian Medical College, Vellore, India.
Lancet Reg Health Southeast Asia. 2024 Aug 21;28:100470. doi: 10.1016/j.lansea.2024.100470. eCollection 2024 Sep.
We measured the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and re-infections in an adult community-based cohort in southern India.
We conducted a 2-year follow-up on 1229 participants enrolled between May and October 2021. Participants provided vaccination histories, weekly saliva samples, and blood samples at 0, 6, 12, and 24 months. Salivary reverse transcription polymerase chain reaction (RT-PCR) and Meso-Scale Discovery panels were used for SARS-CoV-2 detection and anti-spike, anti-nucleocapsid immunoglobulin G quantification. Whole genome sequencing was performed on a subset of positive samples. SARS-CoV-2 infection incidence was measured across Pre-Omicron (May-December 2021), Omicron-I (December 2021-June 2022), and Omicron-II (July 2022-October 2023) periods.
In total, 1166 (95%) participants with 83% seropositivity at baseline completed the follow-up, providing 2205 person-years of observation. Utilizing both RT-PCR and serology we identified 1306 infections and yielded an incidence rate of 591.3 per 1000 person-years (95% confidence interval, 559.6-624.3), which peaked during Omicron-I at 1418.1 per 1000 person-years (95% confidence interval, 1307.4-1535.6). During Omicron-I and II, neither prior infection nor vaccination conferred protection against infection. Overall, 74% of infections were asymptomatic.
Integrated RT-PCR and serology revealed significant SARS-CoV-2 infection frequency, highlighting the prevalence of asymptomatic cases among previously infected or vaccinated individuals. This underscores the effectiveness of combining surveillance strategies when monitoring pandemic trends and confirms the role of non-invasive sampling in ensuring participant compliance, reflecting national transmission patterns.
The study was funded by the Bill and Melinda Gates Foundation.
我们在印度南部一个以社区为基础的成年队列中测量了严重急性呼吸综合征冠状病毒2（SARS-CoV-2）感染和再感染的发生率。
我们对2021年5月至10月招募的1229名参与者进行了为期2年的随访。参与者提供了疫苗接种史、每周唾液样本以及在0、6、12和24个月时的血液样本。使用唾液逆转录聚合酶链反应（RT-PCR）和中尺度发现检测板进行SARS-CoV-2检测以及抗刺突蛋白、抗核衣壳免疫球蛋白G定量。对一部分阳性样本进行了全基因组测序。在奥密克戎毒株出现之前（2021年5月至12月）、奥密克戎毒株I期（2021年12月至2022年6月）和奥密克戎毒株II期（2022年7月至2023年10月）期间测量了SARS-CoV-2感染发生率。
共有1166名（95%）在基线时血清学阳性率为83%的参与者完成了随访，提供了2205人年的观察数据。利用RT-PCR和血清学我们识别出1306例感染，发病率为每1000人年591.3例（95%置信区间，559.6 - 624.3），在奥密克戎毒株I期达到峰值，为每1000人年1418.1例（95%置信区间，1307.4 - 1535.6）。在奥密克戎毒株I期和II期，既往感染和疫苗接种均不能预防感染。总体而言，74%的感染为无症状感染。
综合RT-PCR和血清学显示SARS-CoV-2感染频率较高，突出了既往感染或接种疫苗个体中无症状病例的普遍性。这强调了在监测疫情趋势时结合监测策略的有效性，并证实了非侵入性采样在确保参与者依从性方面的作用，反映了国家传播模式。
该研究由比尔及梅琳达·盖茨基金会资助。
