Household Transmission of the 2009 Pandemic A/H1N1 Influenza Virus: Elevated Laboratory-Confirmed Secondary Attack Rates and Evidence of Asymptomatic Infections
Household Transmission of the 2009 Pandemic A/H1N1 Influenza Virus: Elevated Laboratory-Confirmed Secondary Attack Rates and Evidence of Asymptomatic Infections
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DOI：
10.1086/656582
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发表时间：
2010-11-01
影响因子：
11.8
通讯作者：
Boivin, Guy
中科院分区：
文献类型：
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作者：
Papenburg, Jesse;Baz, Mariana;Boivin, Guy
背景描述2009年甲型H1N1流感病毒（pH 1 N1）的家庭传播特征对于设计有效的公共卫生措施以减缓传播至关重要。我们的目标是在积极的临床随访和实验室确认的结果的基础上，估计二次发病率（SAR）、无症状感染者的比例以及家庭内pH 1 N1传播的危险因素。我们在2009年5月至7月期间（即第一波pH 1 N1大流行期间）在加拿大魁北克市进行了一项前瞻性观察研究。我们评估了42个家庭（包括43名原发病例患者和119名接触者）的pH 1 N1传播情况。在连续家庭访视期间前瞻性收集临床数据。通过临床标准和实验室诊断试验（包括血清学和分子生物学方法）确定继发病例。我们确定了53例实验室确认的pH 1 N1病毒感染继发病例患者，SAR为45%（95%置信区间[CI]，35.6%-53.5%）。34个家庭（81%）有>= 1例确诊的继发病例患者。原发性和确诊继发性病例发病之间的平均连续间隔为3.9天（中位间隔为3天）。29%（95%CI，20.5%-36.7%）的家庭接触者出现流感样疾病（发热和咳嗽或喉咙痛）。5例（9.4%）继发病例无症状。幼儿（！7岁）发生实验室确诊流感样疾病的风险最高。原发病例中腹泻和呕吐并存者最易传播pH 1 N1。pH 1 N1的家庭传播可能比以前估计的要大得多，特别是与包括胃肠道疾病在内的临床表现有关。在家庭中获得的pH 1 N1感染中约有10%可能是无症状的。
Background. Characterizing household transmission of the 2009 pandemic A/H1N1 influenza virus (pH1N1) is critical for the design of effective public health measures to mitigate spread. Our objectives were to estimate the secondary attack rates (SARs), the proportion of asymptomatic infections, and risk factors for pH1N1 transmission within households on the basis of active clinical follow-up and laboratory-confirmed outcomes.Methods. We conducted a prospective observational study during the period May-July 2009 (ie, during the first wave of the pH1N1 pandemic) in Quebec City, Canada. We assessed pH1N1 transmission in 42 households (including 43 primary case patients and 119 contacts). Clinical data were prospectively collected during serial household visits. Secondary case patients were identified by clinical criteria and laboratory diagnostic tests, including serological and molecular methods.Results. We identified 53 laboratory-confirmed secondary case patients with pH1N1 virus infection, for an SAR of 45% (95% confidence interval [CI], 35.6%-53.5%). Thirty-four (81%) of the households had >= 1 confirmed secondary case patient. The mean serial interval between onset of primary and confirmed secondary cases was 3.9 days (median interval, 3 days). Influenza-like illness (fever and cough or sore throat) developed in 29% (95% CI, 20.5%-36.7%) of household contacts. Five (9.4%) of secondary case patients were asymptomatic. Young children (! 7 years of age) were at highest risk of developing laboratory-confirmed influenza-like illness. Primary case patients with both diarrhea and vomiting were the most likely to transmit pH1N1.Conclusion. Household transmission of pH1N1 may be substantially greater than previously estimated, especially in association with clinical presentations that include gastrointestinal complaints. Approximately 10% of pH1N1 infections acquired in the household may be asymptomatic.