Department of Epidemiology and Biostatistics, University of Georgia College of Public Health, Athens.
Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana.
JAMA Intern Med. 2020 Dec 1;180(12):1665-1671. doi: 10.1001/jamainternmed.2020.5225.
Evidence of whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), can be transmitted as an aerosol (ie, airborne) has substantial public health implications.
To investigate potential transmission routes of SARS-CoV-2 infection with epidemiologic evidence from a COVID-19 outbreak.
DESIGN, SETTING, AND PARTICIPANTS: This cohort study examined a community COVID-19 outbreak in Zhejiang province. On January 19, 2020, 128 individuals took 2 buses (60 [46.9%] from bus 1 and 68 [53.1%] from bus 2) on a 100-minute round trip to attend a 150-minute worship event. The source patient was a passenger on bus 2. We compared risks of SARS-CoV-2 infection among at-risk individuals taking bus 1 (n = 60) and bus 2 (n = 67 [source patient excluded]) and among all other individuals (n = 172) attending the worship event. We also divided seats on the exposed bus into high-risk and low-risk zones according to the distance from the source patient and compared COVID-19 risks in each zone. In both buses, central air conditioners were in indoor recirculation mode.
SARS-CoV-2 infection was confirmed by reverse transcription polymerase chain reaction or by viral genome sequencing results. Attack rates for SARS-CoV-2 infection were calculated for different groups, and the spatial distribution of individuals who developed infection on bus 2 was obtained.
Of the 128 participants, 15 (11.7%) were men, 113 (88.3%) were women, and the mean age was 58.6 years. On bus 2, 24 of the 68 individuals (35.3% [including the index patient]) received a diagnosis of COVID-19 after the event. Meanwhile, none of the 60 individuals in bus 1 were infected. Among the other 172 individuals at the worship event, 7 (4.1%) subsequently received a COVID-19 diagnosis. Individuals in bus 2 had a 34.3% (95% CI, 24.1%-46.3%) higher risk of getting COVID-19 compared with those in bus 1 and were 11.4 (95% CI, 5.1-25.4) times more likely to have COVID-19 compared with all other individuals attending the worship event. Within bus 2, individuals in high-risk zones had moderately, but nonsignificantly, higher risk for COVID-19 compared with those in the low-risk zones. The absence of a significantly increased risk in the part of the bus closer to the index case suggested that airborne spread of the virus may at least partially explain the markedly high attack rate observed.
In this cohort study and case investigation of a community outbreak of COVID-19 in Zhejiang province, individuals who rode a bus to a worship event with a patient with COVID-19 had a higher risk of SARS-CoV-2 infection than individuals who rode another bus to the same event. Airborne spread of SARS-CoV-2 seems likely to have contributed to the high attack rate in the exposed bus. Future efforts at prevention and control must consider the potential for airborne spread of the virus.
有证据表明，导致 2019 年冠状病毒病（COVID-19）的严重急性呼吸系统综合征冠状病毒 2（SARS-CoV-2）是否可以作为气溶胶（即空气传播）传播，这对公共卫生具有重大意义。
利用 COVID-19 暴发的流行病学证据，研究 SARS-CoV-2 感染的潜在传播途径。
设计、地点和参与者：本队列研究调查了浙江省的一次社区 COVID-19 暴发。2020 年 1 月 19 日，128 人乘坐 2 辆公共汽车（60 人[46.9%]来自公共汽车 1，68 人[53.1%]来自公共汽车 2）进行了 100 分钟的往返旅行，参加了 150 分钟的礼拜活动。源患者是公共汽车 2 上的一名乘客。我们比较了乘坐公共汽车 1（n=60）和公共汽车 2（n=67[源患者除外]）的高危人群以及参加礼拜活动的所有其他人群（n=172）中 SARS-CoV-2 感染的风险。我们还根据与源患者的距离将暴露公共汽车上的座位划分为高风险区和低风险区，并比较了每个区的 COVID-19 风险。在两辆公共汽车中，中央空调均处于室内再循环模式。
通过逆转录聚合酶链反应或病毒基因组测序结果确认 SARS-CoV-2 感染。计算了不同组的 SARS-CoV-2 感染率，并获得了在公共汽车 2 上发生感染的个体的空间分布。
在 128 名参与者中，15 名（11.7%）为男性，113 名（88.3%）为女性，平均年龄为 58.6 岁。在公共汽车 2 上，68 名乘客中（包括指数患者）有 24 人在活动后被诊断出 COVID-19。同时，公共汽车 1 中的 60 人未被感染。在礼拜活动的其他 172 名参与者中，有 7 人（4.1%）随后被诊断出 COVID-19。与乘坐公共汽车 1 的人相比，乘坐公共汽车 2 的人患 COVID-19 的风险高 34.3%（95%CI，24.1%-46.3%），与参加礼拜活动的所有其他参与者相比，患 COVID-19 的风险高 11.4 倍（95%CI，5.1-25.4）。在公共汽车 2 内，高风险区的个体感染 COVID-19 的风险略高，但无统计学意义，而低风险区的个体感染 COVID-19 的风险则明显高于低风险区。靠近指数病例的公共汽车部分没有显著增加的风险表明，病毒的空气传播可能至少部分解释了观察到的高发病率。
在这项对浙江省 COVID-19 社区暴发的队列研究和病例调查中，乘坐公共汽车前往有 COVID-19 患者的礼拜活动的个体感染 SARS-CoV-2 的风险高于乘坐另一辆公共汽车前往同一活动的个体。SARS-CoV-2 的空气传播似乎很可能导致了暴露公共汽车上的高发病率。未来的预防和控制工作必须考虑到病毒空气传播的可能性。
