Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers A Randomized Controlled Trial
Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers A Randomized Controlled Trial
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DOI：
10.7326/m20-6817
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发表时间：
2021-03-01
影响因子：
39.2
通讯作者：
Iversen, Kasper
中科院分区：
文献类型：
--
作者：
Bundgaard, Henning;Bundgaard, Johan Skov;Iversen, Kasper
背景：观察证据表明，戴口罩可减少严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的传播。目前还不确定这种观察到的关联是否是通过保护未感染的佩戴者而产生的（保护作用），通过减少受感染口罩佩戴者的传播目的：评估在口罩不常见且不属于推荐的公共卫生措施的环境中，建议在家庭外使用外科口罩是否可以降低佩戴者感染SARS-CoV-2的风险。设计：随机对照试验（DANMASK-19 [丹麦评估口罩预防COVID-19感染的研究]）。（临床试验政府网站：NCT 04337541）背景：丹麦，2020年4月和5月。参与者：每天在户外活动超过3小时而不使用职业口罩的成年人。干预：鼓励遵守2019年冠状病毒病的社交距离措施，加上不建议佩戴口罩或建议外出时与其他人一起佩戴口罩，以及供应50个外科口罩，测量：主要结果是通过抗体检测、聚合酶链反应（PCR）或医院诊断在1个月时口罩佩戴者中的SARS-CoV-2感染。次要结果是其他呼吸道病毒的PCR阳性。结果：共有3030名参与者被随机分配到建议戴口罩，2994人被分配到对照组; 4862人完成了研究。42名推荐使用口罩的参与者（1.8%）和53名对照参与者（2.1%）发生了SARS-CoV 2感染。组间差异为-0.3个百分点（95% CI，-1.2至0.4个百分点; P=0.38）（比值比，0.82 [CI，0.54至1.23]; P=0.33）。考虑失访的多重插补产生了相似的结果。虽然观察到的差异在统计学上不显著，但95%CI与46%的感染减少到23%的感染增加是一致的。局限性：不确定的结果，缺失的数据，可变的依从性，患者报告的家庭测试结果，没有盲法，没有评估口罩是否可以减少疾病从口罩佩戴者传播给其他人。建议佩戴外科口罩以补充其他公共卫生措施，并没有使佩戴者的SARS-CoV-2感染率降低50%以上，因为社区感染率适中，存在一定程度的社交距离，并且一般口罩使用不常见。这些数据与较低程度的自我保护是一致的。
Background: Observational evidence suggests that mask wearing mitigates transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is uncertain if this observed association arises through protection of uninfected wearers (protective effect), via reduced transmission from infected mask wearers (source control), or both.Objective: To assess whether recommending surgical mask use outside the home reduces wearers' risk for SARS-CoV-2 infection in a setting where masks were uncommon and not among recommended public health measures.Design: Randomized controlled trial (DANMASK-19 [Danish Study to Assess Face Masks for the Protection Against COVID-19 Infection]). (ClinicalTrials.gov: NCT04337541)Setting: Denmark, April and May 2020.Participants: Adults spending more than 3 hours per day outside the home without occupational mask use.Intervention: Encouragement to follow social distancing measures for coronavirus disease 2019, plus either no mask recommendation or a recommendation to wear a mask when outside the home among other persons together with a supply of 50 surgical masks and instructions for proper use.Measurements: The primary outcome was SARS-CoV-2 infection in the mask wearer at 1 month by antibody testing, polymerase chain reaction (PCR), or hospital diagnosis. The secondary outcome was PCR positivity for other respiratory viruses.Results: A total of 3030 participants were randomly assigned to the recommendation to wear masks, and 2994 were assigned to control; 4862 completed the study. Infection with SARS-CoV2 occurred in 42 participants recommended masks (1.8%) and 53 control participants (2.1%). The between-group difference was -0.3 percentage point (95% CI, -1.2 to 0.4 percentage point; P=0.38) (odds ratio, 0.82 [CI, 0.54 to 1.23]; P=0.33). Multiple imputation accounting for loss to follow-up yielded similar results. Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection.Limitation: Inconclusive results, missing data, variable adherence, patient-reported findings on home tests, no blinding, and no assessment of whether masks could decrease disease transmission from mask wearers to others.Conclusion: The recommendation to wear surgical masks to supplement other public health measures did not reduce the SARS-CoV-2 infection rate among wearers by more than 50% in a community with modest infection rates, some degree of social distancing, and uncommon general mask use. The data were compatible with lesser degrees of self-protection.