From the University of Minnesota (D.R.B., M.F.P., A.S.B., K.A.P., S.M.L., E.C.O., C.P.S., A.A.N., M.R.N., M.A., N.W.E., R.R., K.H.H.) and M Health Fairview Investigational Drug Service Pharmacy (D.L.), Minneapolis; and the Research Institute of the McGill University Health Centre and the Clinical Practice Assessment Unit, Department of Medicine, McGill University, Montreal (M.P.C., E.G.M., T.C.L.), the Department of Internal Medicine, University of Manitoba (S.A.L., L.J.M., G.D., N.M., R.Z.), the Research Institute in Oncology and Hematology, CancerCare Manitoba, University of Manitoba (R.Z.), and the George and Fay Yee Centre for Healthcare Innovation (L.E.K.), Winnipeg, and the University of Alberta, Edmonton (I.S.S.) - all in Canada.
N Engl J Med. 2020 Aug 6;383(6):517-525. doi: 10.1056/NEJMoa2016638. Epub 2020 Jun 3.
Coronavirus disease 2019 (Covid-19) occurs after exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For persons who are exposed, the standard of care is observation and quarantine. Whether hydroxychloroquine can prevent symptomatic infection after SARS-CoV-2 exposure is unknown.
We conducted a randomized, double-blind, placebo-controlled trial across the United States and parts of Canada testing hydroxychloroquine as postexposure prophylaxis. We enrolled adults who had household or occupational exposure to someone with confirmed Covid-19 at a distance of less than 6 ft for more than 10 minutes while wearing neither a face mask nor an eye shield (high-risk exposure) or while wearing a face mask but no eye shield (moderate-risk exposure). Within 4 days after exposure, we randomly assigned participants to receive either placebo or hydroxychloroquine (800 mg once, followed by 600 mg in 6 to 8 hours, then 600 mg daily for 4 additional days). The primary outcome was the incidence of either laboratory-confirmed Covid-19 or illness compatible with Covid-19 within 14 days.
We enrolled 821 asymptomatic participants. Overall, 87.6% of the participants (719 of 821) reported a high-risk exposure to a confirmed Covid-19 contact. The incidence of new illness compatible with Covid-19 did not differ significantly between participants receiving hydroxychloroquine (49 of 414 [11.8%]) and those receiving placebo (58 of 407 [14.3%]); the absolute difference was -2.4 percentage points (95% confidence interval, -7.0 to 2.2; P = 0.35). Side effects were more common with hydroxychloroquine than with placebo (40.1% vs. 16.8%), but no serious adverse reactions were reported.
After high-risk or moderate-risk exposure to Covid-19, hydroxychloroquine did not prevent illness compatible with Covid-19 or confirmed infection when used as postexposure prophylaxis within 4 days after exposure. (Funded by David Baszucki and Jan Ellison Baszucki and others; ClinicalTrials.gov number, NCT04308668.).
新型冠状病毒病 2019（Covid-19）发生在接触严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）后。对于接触过的人，标准的治疗方法是观察和隔离。羟氯喹是否能预防 SARS-CoV-2 暴露后的症状性感染尚不清楚。
我们在美国和加拿大的部分地区进行了一项随机、双盲、安慰剂对照试验，测试羟氯喹作为暴露后预防。我们招募了那些在距离不到 6 英尺的地方与确诊的 Covid-19 患者有家庭或职业接触，且接触时间超过 10 分钟，同时没有佩戴口罩或眼罩（高风险接触），或者虽然佩戴了口罩但没有佩戴眼罩（中风险接触）的成年人。在暴露后 4 天内，我们随机分配参与者接受安慰剂或羟氯喹（一次 800mg，6-8 小时后再服 600mg，然后每天 600mg，再服用 4 天）。主要结局是在 14 天内发生实验室确诊的 Covid-19 或与 Covid-19 相符的疾病。
我们招募了 821 名无症状参与者。总体而言，87.6%的参与者（821 名中的 719 名）报告了与确诊的 Covid-19 接触者的高风险接触。接受羟氯喹治疗的参与者（414 名中的 49 名，11.8%）和接受安慰剂治疗的参与者（407 名中的 58 名，14.3%）中，新发生的与 Covid-19 相符的疾病的发生率没有显著差异；绝对差异为-2.4 个百分点（95%置信区间，-7.0 至 2.2；P=0.35）。与安慰剂相比，羟氯喹更常见副作用（40.1%比 16.8%），但没有严重的不良反应报告。
在接触 Covid-19 高风险或中风险后，在接触后 4 天内使用羟氯喹作为暴露后预防，不能预防与 Covid-19 相符的疾病或确诊感染。（由 David Baszucki 和 Jan Ellison Baszucki 等人资助；ClinicalTrials.gov 编号，NCT04308668。）
