Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore.
Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore.
Int J Infect Dis. 2022 Feb;115:72-78. doi: 10.1016/j.ijid.2021.11.043. Epub 2021 Dec 2.
Since January 2020, Singapore has implemented comprehensive measures to suppress SARS-CoV-2. Despite this, the country has experienced contrasting epidemics, with limited transmission in the community and explosive outbreaks in migrant worker dormitories.
To estimate SARS-CoV-2 infection incidence among migrant workers and the general population in Singapore.
Prospective serological cohort studies.
Two cohort studies - in a migrant worker dormitory and in the general population in Singapore.
478 residents of a SARS-CoV-2-affected migrant worker dormitory were followed up between May and July 2020, with blood samples collected on recruitment and after 2 and 6 weeks. In addition, 937 community-dwelling adult Singapore residents, for whom pre-pandemic sera were available, were recruited. These individuals also provided a serum sample on recruitment in November/December 2020.
Exposure to SARS-CoV-2 in a densely populated migrant worker dormitory and in the general population.
The main outcome measures were the incidences of SARS-CoV-2 infection in migrant workers and in the general population, as determined by the detection of neutralizing antibodies against SARS-CoV-2, and adjusting for assay sensitivity and specificity using a Bayesian modeling framework.
No evidence of community SARS-CoV-2 exposure was found in Singapore prior to September 2019. It was estimated that < 2 per 1000 adult residents in the community were infected with SARS-CoV-2 in 2020 (cumulative seroprevalence: 0.16%; 95% CrI: 0.008-0.72%). Comparison with comprehensive national case notification data suggested that around 1 in 4 infections in the general population were associated with symptoms. In contrast, in the migrant worker cohort, almost two-thirds had been infected by July 2020 (cumulative seroprevalence: 63.8%; 95% CrI: 57.9-70.3%); no symptoms were reported in almost all of these infections.
Our findings demonstrate that SARS-CoV-2 suppression is possible with strict and rapid implementation of border restrictions, case isolation, contact tracing, quarantining, and social-distancing measures. However, the risk of large-scale epidemics in densely populated environments requires specific consideration in preparedness planning. Prioritization of these settings in vaccination strategies should minimize the risk of future resurgences and potential spillover of transmission to the wider community.
自 2020 年 1 月以来，新加坡已实施综合措施来抑制 SARS-CoV-2。尽管如此，该国仍经历了截然不同的疫情，社区内传播有限，而移民工人宿舍则爆发了疫情。
估计新加坡移民工人和普通人群中 SARS-CoV-2 的感染发生率。
前瞻性血清队列研究。
在新加坡的一个 SARS-CoV-2 感染的移民工人宿舍和普通人群中进行的两项队列研究。
2020 年 5 月至 7 月期间，对 SARS-CoV-2 影响的移民工人宿舍的 478 名居民进行了随访，在招募时以及 2 周和 6 周后采集了血液样本。此外，招募了 937 名居住在社区中的成年新加坡居民，他们在大流行前有血清样本。这些人还在 2020 年 11 月/ 12 月招募时提供了血清样本。
在人口稠密的移民工人宿舍和普通人群中接触 SARS-CoV-2。
主要结局是通过检测针对 SARS-CoV-2 的中和抗体来确定移民工人和普通人群中 SARS-CoV-2 感染的发生率，并使用贝叶斯建模框架调整检测灵敏度和特异性。
在 2019 年 9 月之前，没有证据表明新加坡社区中存在 SARS-CoV-2 暴露。据估计，2020 年社区中每 1000 名成年居民中不到 2 人感染 SARS-CoV-2（累计血清阳性率：0.16%；95%CrI：0.008-0.72%）。与综合国家病例报告数据的比较表明，普通人群中约有 1/4 的感染与症状有关。相比之下，在移民工人队列中，到 2020 年 7 月几乎有三分之二的人已经感染（累计血清阳性率：63.8%；95%CrI：57.9-70.3%）；几乎所有这些感染都没有报告症状。
我们的研究结果表明，通过严格快速地实施边境限制、病例隔离、接触者追踪、检疫和社交距离措施，可以实现 SARS-CoV-2 的抑制。然而，在人口密集环境中发生大规模疫情的风险需要在备灾规划中加以特别考虑。在疫苗接种策略中优先考虑这些环境应最大限度地降低未来疫情复发和潜在传播给更广泛社区的风险。
