Epidemiological Investigation Team, Central Disease Control Headquarters, Korea Disease Control and Prevention Agency, Cheongju, Korea.
Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea.
J Korean Med Sci. 2022 Jan 3;37(1):e12. doi: 10.3346/jkms.2022.37.e12.
Despite the extraordinary speed of mass vaccination efforts, an outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delta variant in a vaccinee with coronavirus disease 2019 (COVID-19) mRNA vaccine was identified in an adult day service center (ADSC) of Jeju, South Korea. The primary objective of this study was to investigate the epidemiologic features in infection-vulnerable facilities with a high vaccination rate of BNT162b2 mRNA COVID-19 vaccine. The second was to estimate the secondary transmission prevention effect of the vaccine in the household members by vaccination status.
We included all ADSC participants, staff and their household members. All COVID-19 infected cases were confirmed by reverse transcriptase polymerase chain reaction. We calculated attack rate in ADSC and the secondary attack rate (SAR) in household members by vaccination status.
Among a total of 42 participants and 16 staff, of which 96.6% were fully vaccinated with BNT162b2 mRNA COVID-19 vaccine, 12 symptomatic cases and 13 asymptomatic confirmed cases of COVID-19 were found. The attack rate was 43.1%, with 13 isolates identified as SARS-CoV-2 virus, delta variant. The SAR in unvaccinated and partially vaccinated household members were 27.8% (5/18) and 25.0% (5/20), respectively, while the SAR in fully vaccinated household members was 12.5% (1/8).
We describe a SARS-CoV-2 delta variant outbreak in ADSC with high vaccine coverage rate, characterized by high infection rate, high transmissibility, and low clinical severity. The outbreak proceeded to unvaccinated or partially vaccinated household members, emphasizing the need for immunizing close contacts of high-risk groups.
尽管大规模疫苗接种工作进展迅速，但在韩国济州岛的一家成人日间服务中心（ADSC），仍发现了一名接种过 2019 年冠状病毒病（COVID-19）mRNA 疫苗的疫苗接种者感染了严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）delta 变体。本研究的主要目的是调查高接种率 BNT162b2 mRNA COVID-19 疫苗的易感感染设施中的流行病学特征。其次是根据疫苗接种状况估计疫苗对家庭接触者的二次传播预防效果。
我们纳入了所有 ADSC 参与者、工作人员及其家庭成员。所有 COVID-19 感染病例均通过逆转录酶聚合酶链反应（RT-PCR）确诊。我们根据疫苗接种状况计算了 ADSC 的发病率和家庭接触者的二代发病率（SAR）。
在总共 42 名参与者和 16 名工作人员中，96.6%的人完全接种了 BNT162b2 mRNA COVID-19 疫苗，发现了 12 例有症状病例和 13 例无症状确诊 COVID-19 病例。发病率为 43.1%，共分离出 13 株 SARS-CoV-2 病毒，delta 变体。未接种和部分接种疫苗的家庭成员的 SAR 分别为 27.8%（5/18）和 25.0%（5/20），而完全接种疫苗的家庭成员的 SAR 为 12.5%（1/8）。
我们描述了一起在高疫苗接种率的 ADSC 中发生的 SARS-CoV-2 delta 变体暴发事件，其特征是感染率高、传染性强、临床严重程度低。疫情蔓延至未接种或部分接种疫苗的家庭成员，这强调了为高风险人群的密切接触者接种疫苗的必要性。
