COVID-19 Rapid Evidence Service, UK Health Security Agency, London, UK
COVID-19 Rapid Evidence Service, UK Health Security Agency, London, UK.
BMJ. 2022 Jun 29;377:e068743. doi: 10.1136/bmj-2021-068743.
To evaluate the potential for long distance airborne transmission of SARS-CoV-2 in indoor community settings and to investigate factors that might influence transmission.
Rapid systematic review and narrative synthesis.
Medline, Embase, medRxiv, Arxiv, and WHO COVID-19 Research Database for studies published from 27 July 2020 to 19 January 2022; existing relevant rapid systematic review for studies published from 1 January 2020 to 27 July 2020; and citation analysis in Web of Science and Cocites.
Observational studies reporting on transmission events in indoor community (non-healthcare) settings in which long distance airborne transmission of SARS-CoV-2 was the most likely route. Studies such as those of household transmission where the main transmission route was likely to be close contact or fomite transmission were excluded.
Data extraction was done by one reviewer and independently checked by a second reviewer. Primary outcomes were SARS-CoV-2 infections through long distance airborne transmission (>2 m) and any modifying factors. Methodological quality of included studies was rated using the quality criteria checklist, and certainty of primary outcomes was determined using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. Narrative synthesis was themed by setting.
22 reports relating to 18 studies were identified (methodological quality was high in three, medium in five, and low in 10); all the studies were outbreak investigations. Long distance airborne transmission was likely to have occurred for some or all transmission events in 16 studies and was unclear in two studies (GRADE: very low certainty). In the 16 studies, one or more factors plausibly increased the likelihood of long distance airborne transmission, particularly insufficient air replacement (very low certainty), directional air flow (very low certainty), and activities associated with increased emission of aerosols, such as singing or speaking loudly (very low certainty). In 13 studies, the primary cases were reported as being asymptomatic, presymptomatic, or around symptom onset at the time of transmission. Although some of the included studies were well conducted outbreak investigations, they remain at risk of bias owing to study design and do not always provide the level of detail needed to fully assess transmission routes.
This rapid systematic review found evidence suggesting that long distance airborne transmission of SARS-CoV-2 might occur in indoor settings such as restaurants, workplaces, and venues for choirs, and identified factors such as insufficient air replacement that probably contributed to transmission. These results strengthen the need for mitigation measures in indoor settings, particularly the use of adequate ventilation.
PROSPERO CRD42021236762.
评估 SARS-CoV-2 在室内社区环境中长距离空气传播的潜力，并研究可能影响传播的因素。
快速系统评价和叙述性综合。
从 2020 年 7 月 27 日至 2022 年 1 月 19 日，检索 Medline、Embase、medRxiv、Arxiv 和世卫组织 COVID-19 研究数据库中发表的研究；对 2020 年 1 月 1 日至 2020 年 7 月 27 日发表的现有相关快速系统评价进行检索；并对 Web of Science 和 Cocites 中的引文进行分析。
报告 SARS-CoV-2 在室内社区（非医疗保健）环境中传播事件的观察性研究，其中长距离空气传播是最有可能的途径。排除了那些主要传播途径可能是密切接触或接触传播的家庭传播研究。
由一名评审员进行数据提取，另一名评审员独立检查。主要结局是通过长距离空气传播（>2 米）感染 SARS-CoV-2 和任何修饰因素。使用质量标准检查表评价纳入研究的方法学质量，并使用推荐评估、制定和评估（GRADE）框架确定主要结局的确定性。叙述性综合按环境进行主题划分。
确定了 22 份与 18 项研究相关的报告（其中 3 项研究的方法学质量较高，5 项研究的方法学质量中等，10 项研究的方法学质量较低）；所有研究均为暴发调查。在 16 项研究中，长距离空气传播可能发生在一些或所有传播事件中，在两项研究中不明确（GRADE：极低确定性）。在 16 项研究中，一个或多个因素可能增加了长距离空气传播的可能性，特别是空气置换不足（极低确定性）、定向气流（极低确定性）以及与气溶胶排放增加相关的活动，例如大声唱歌或说话（极低确定性）。在 13 项研究中，主要病例报告在传播时为无症状、前驱症状或接近症状发作。尽管一些纳入的研究是经过良好设计的暴发调查，但由于研究设计，它们仍然存在偏倚风险，并且并不总是提供充分评估传播途径所需的详细信息。
这项快速系统评价发现的证据表明，SARS-CoV-2 可能在室内环境中通过长距离空气传播，如餐厅、工作场所和合唱团场所，并确定了一些因素，如空气置换不足，可能有助于传播。这些结果加强了在室内环境中采取缓解措施的必要性，特别是要充分利用适当的通风。
PROSPERO CRD42021236762。
