Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
PLoS Med. 2010 May 18;7(5):e1000277. doi: 10.1371/journal.pmed.1000277.
To date, little is known about the initial spread and response to the 2009 pandemic of novel influenza A ("2009 H1N1") in tropical countries. Here, we analyse the early progression of the epidemic from 26 May 2009 until the establishment of community transmission in the second half of July 2009 in Ho Chi Minh City (HCMC), Vietnam. In addition, we present detailed systematic viral clearance data on 292 isolated and treated patients and the first three cases of selection of resistant virus during treatment in Vietnam.
Data sources included all available health reports from the Ministry of Health and relevant health authorities as well as clinical and laboratory data from the first confirmed cases isolated at the Hospital for Tropical Diseases in HCMC. Extensive reverse transcription (RT)-PCR diagnostics on serial samples, viral culture, neuraminidase-inhibition testing, and sequencing were performed on a subset of 2009 H1N1 confirmed cases. Virological (PCR status, shedding) and epidemiological (incidence, isolation, discharge) data were combined to reconstruct the initial outbreak and the establishment of community transmission. From 27 April to 24 July 2009, approximately 760,000 passengers who entered HCMC on international flights were screened at the airport by a body temperature scan and symptom questionnaire. Approximately 0.15% of incoming passengers were intercepted, 200 of whom tested positive for 2009 H1N1 by RT-PCR. An additional 121 out of 169 nontravelers tested positive after self-reporting or contact tracing. These 321 patients spent 79% of their PCR-positive days in isolation; 60% of PCR-positive days were spent treated and in isolation. Influenza-like illness was noted in 61% of patients and no patients experienced pneumonia or severe outcomes. Viral clearance times were similar among patient groups with differing time intervals from illness onset to treatment, with estimated median clearance times between 2.6 and 2.8 d post-treatment for illness-to-treatment intervals of 1-4 d, and 2.0 d (95% confidence interval 1.5-2.5) when treatment was started on the first day of illness.
The patients described here represent a cross-section of infected individuals that were identified by temperature screening and symptom questionnaires at the airport, as well as mildly symptomatic to moderately ill patients who self-reported to hospitals. Data are observational and, although they are suggestive, it is not possible to be certain whether the containment efforts delayed community transmission in Vietnam. Viral clearance data assessed by RT-PCR showed a rapid therapeutic response to oseltamivir.
迄今为止，人们对于 2009 年新型甲型流感（“2009 年 H1N1”）在热带国家的初始传播和应对情况知之甚少。在这里，我们分析了从 2009 年 5 月 26 日至 7 月下旬在越南胡志明市（HCMC）建立社区传播之间的疫情早期进展。此外，我们提供了有关 292 例隔离和治疗患者的详细系统病毒清除数据，以及越南首例治疗中耐药病毒选择的三个病例。
数据来源包括卫生部和相关卫生当局的所有现有卫生报告，以及在胡志明市热带病医院隔离的首例确诊病例的临床和实验室数据。对 2009 年 H1N1 确诊病例的一个亚组进行了广泛的逆转录（RT）-PCR 诊断、病毒培养、神经氨酸酶抑制试验和测序。病毒学（PCR 状态，脱落）和流行病学（发病率，隔离，出院）数据相结合，以重建初始暴发和建立社区传播。从 2009 年 4 月 27 日至 7 月 24 日，约有 76 万名乘国际航班进入 HCMC 的乘客在机场接受体温扫描和症状问卷调查。大约拦截了 0.15％的入境旅客，其中有 200 名通过 RT-PCR 检测出 2009 年 H1N1 呈阳性。另有 169 名非旅行者在自我报告或接触追踪后检测出 121 例阳性。这 321 例患者在隔离期间度过了 79％的 PCR 阳性天数；60％的 PCR 阳性天数接受治疗并隔离。61％的患者出现流感样疾病，没有患者发生肺炎或严重后果。清除病毒的时间在发病至治疗时间间隔不同的患者群体中相似，在治疗开始于发病的第一天时，治疗至治疗间隔为 1-4 天的估计中位清除时间为 2.6-2.8 天，而 2.0 天（95％置信区间为 1.5-2.5）。
这里描述的患者代表了通过机场体温筛查和症状问卷调查，以及轻度症状到中度症状的自我报告至医院的感染人群的一个横断面。数据是观察性的，尽管提示性很强，但尚无法确定遏制措施是否延迟了越南的社区传播。通过 RT-PCR 评估的病毒清除数据显示奥司他韦治疗的快速疗效。
