Biodefence Centre, Ministry of Defence, Department of Epidemiology and Public Health, National University of Singapore.
N Engl J Med. 2010 Jun 10;362(23):2166-74. doi: 10.1056/NEJMoa0908482.
From June 22 through June 25, 2009, four outbreaks of infection with the pandemic influenza A (H1N1) virus occurred in Singapore military camps. We report the efficacy of ring chemoprophylaxis (geographically targeted containment by means of prophylaxis) with oseltamivir to control outbreaks of 2009 H1N1 influenza in semiclosed environments.
All personnel with suspected infection were tested and clinically isolated if infection was confirmed. In addition, we administered postexposure ring chemoprophylaxis with oseltamivir and segregated the affected military units to contain the spread of the virus. All personnel were screened three times weekly both for virologic infection, by means of nasopharyngeal swabs and reverse-transcriptase-polymerase-chain-reaction assay with sequencing, and for clinical symptoms, by means of questionnaires.
A total of 1175 personnel were at risk across the four sites, with 1100 receiving oseltamivir prophylaxis. A total of 75 personnel (6.4%) were infected before the intervention, and 7 (0.6%) after the intervention. There was a significant reduction in the overall reproductive number (the number of new cases attributable to the index case), from 1.91 (95% credible interval, 1.50 to 2.36) before the intervention to 0.11 (95% credible interval, 0.05 to 0.20) after the intervention. Three of the four outbreaks showed a significant reduction in the rate of infection after the intervention. Molecular analysis revealed that all four outbreaks were derived from the New York lineage of the 2009 H1N1 virus and that cases within each outbreak were due to transmission rather than unrelated episodes of infection. Of the 816 personnel treated with oseltamivir who were surveyed, 63 (7.7%) reported mild, nonrespiratory side effects of the drug, with no severe adverse events.
Oseltamivir ring chemoprophylaxis, together with prompt identification and isolation of infected personnel, was effective in reducing the impact of outbreaks of 2009 H1N1 influenza in semiclosed settings.
2009 年 6 月 22 日至 25 日，新加坡军营发生了四起大流行性流感 A（H1N1）病毒感染暴发。我们报告了奥司他韦环形化学预防（通过预防进行地理目标控制）控制半封闭环境中 2009 年 H1N1 流感暴发的效果。
对所有疑似感染的人员进行检测，如果感染得到确认，则进行临床隔离。此外，我们还使用奥司他韦进行了接触后环形化学预防，并将受影响的军事单位隔离开来，以阻止病毒传播。所有人员每周接受三次筛查，通过鼻咽拭子和逆转录-聚合酶链反应检测进行病毒学感染检测，并通过问卷调查进行临床症状检测。
四个地点共有 1175 人面临风险，其中 1100 人接受了奥司他韦预防。在干预前，共有 75 人（6.4%）感染，干预后有 7 人（0.6%）感染。总体繁殖数（归因于指数病例的新病例数）显著降低，从干预前的 1.91（95%可信区间，1.50 至 2.36）降至干预后的 0.11（95%可信区间，0.05 至 0.20）。四个暴发中的三个在干预后感染率显著降低。分子分析显示，所有四个暴发均源自 2009 年 H1N1 病毒的纽约谱系，每个暴发内的病例均是由传播引起的，而不是无关的感染事件。在接受奥司他韦治疗的 816 名接受调查的人员中，有 63 人（7.7%）报告了该药物的轻度、非呼吸道副作用，没有严重的不良事件。
奥司他韦环形化学预防加上及时识别和隔离感染人员，可有效降低半封闭环境中 2009 年 H1N1 流感暴发的影响。
