Biodefence Centre, Ministry of Defence, Transit Road, Singapore 778910, Singapore.
BMC Infect Dis. 2010 Jun 10;10:164. doi: 10.1186/1471-2334-10-164.
Anti-viral prophylaxis is used to prevent the transmission of influenza. We studied serological confirmation of 2009 Influenza A (H1N1) infections during oseltamivir prophylaxis and after cessation of prophylaxis.
Between 22 Jun and 16 Jul 09, we performed a cohort study in 3 outbreaks in the Singapore military where post-exposure oseltamivir ring chemoprophylaxis (75 mg daily for 10 days) was administered. The entire cohort was screened by RT-PCR (with HA gene primers) using nasopharyngeal swabs three times a week. Three blood samples were taken for haemagglutination inhibition testing--at the start of outbreak, 2 weeks after completion of 10 day oseltamivir prophylaxis, and 3 weeks after the pandemic's peak in Singapore. Questionnaires were also administered to collect clinical symptoms.
237 personnel were included for analysis. The overall infection rate of 2009 Influenza A (H1N1) during the three outbreaks was 11.4% (27/237). This included 11 index cases and 16 personnel (7.1%) who developed four-fold or higher rise in antibody titres during oseltamivir prophylaxis. Of these 16 personnel, 8 (3.5%) were symptomatic while the remaining 8 personnel (3.5%) were asymptomatic and tested negative on PCR. Post-cessation of prophylaxis, an additional 23 (12.1%) seroconverted. There was no significant difference in mean fold-rise in GMT between those who seroconverted during and post-prophylaxis (11.3 vs 11.7, p = 0.888). No allergic, neuropsychiatric or other severe side-effects were noted.
Post-exposure oseltamivir prophylaxis reduced the rate of infection during outbreaks, and did not substantially increase subsequent infection rates upon cessation. Asymptomatic infections occur during prophylaxis, which may confer protection against future infection. Post-exposure prophylaxis is effective as a measure in mitigating pandemic influenza outbreaks.
抗病毒预防用于预防流感的传播。我们研究了在奥司他韦预防和预防停止后对 2009 年甲型流感（H1N1）感染的血清学确认。
在 2009 年 6 月 22 日至 7 月 16 日期间，我们在新加坡军队的 3 次暴发中进行了队列研究，在那里进行了接触后奥司他韦环化学预防（每天 75 毫克，持续 10 天）。使用鼻咽拭子每周三次通过 RT-PCR（使用 HA 基因引物）对整个队列进行筛查。在暴发开始时、完成 10 天奥司他韦预防后 2 周以及新加坡大流行高峰期后 3 周，采集了 3 份血液样本进行血凝抑制试验。还进行了问卷调查以收集临床症状。
共有 237 人进行了分析。在这 3 次暴发中，2009 年甲型流感（H1N1）的总体感染率为 11.4%（27/237）。这包括 11 例索引病例和 16 名在奥司他韦预防期间抗体滴度升高 4 倍或更高的人员。在这 16 名人员中，有 8 名（3.5%）出现症状，而其余 8 名（3.5%）无症状且 PCR 检测为阴性。在预防停止后，又有 23 人（12.1%）血清转化。在预防期间和之后血清转化率之间的平均 GMT 升高无显着差异（11.3 对 11.7，p = 0.888）。没有观察到过敏、神经精神或其他严重副作用。
接触后奥司他韦预防可降低暴发期间的感染率，并且在预防停止后不会显着增加随后的感染率。在预防期间发生无症状感染，这可能会提供对未来感染的保护。接触后预防是减轻大流行性流感暴发的有效措施。
