Epidemic Intelligence Service, Scientific Education and Professional Development Program Office, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. (
Clin Infect Dis. 2011 Sep;53(5):455-62. doi: 10.1093/cid/cir437.
Understanding transmissibility of influenza viruses within households is critical for guiding public health response to pandemics. We studied serologically confirmed infection and disease among household contacts of index case patients with 2009 pandemic influenza A (H1N1) virus (pH1N1) infection in a setting of minimal community pH1N1 transmission.
We defined index case patients as students and staff of a New York City high school with laboratory-confirmed pH1N1 infection during the earliest phase of the pH1N1 outbreak in April 2009. We visited households of index case patients twice, once in early May and again in June/July 2009. At each visit, household members (both index case patents and household contacts) provided serum samples and completed questionnaires about illness and possible risk factors. Serologic testing was performed using microneutralization and hemagglutination-inhibition assays.
Of 79 eligible household contacts in 28 households, 19% had serologically confirmed pH1N1 infection, and 28% of those infected were asymptomatic. Serologically confirmed infection varied by age among household contacts: 36% of contacts younger than 10 years were infected, compared with 46% of contacts age 10-18 years, 8% of contacts aged 19-54 years, and 22% of contacts aged 55 years and older.
Infection rates were high for household contacts of persons with confirmed pH1N1, particularly for contacts aged 10-18 years, and asymptomatic infection was common. Efforts to reduce household transmission during influenza pandemics are important adjuncts to strategies to reduce community illness.
了解流感病毒在家庭内的传播能力对于指导大流行期间的公共卫生应对至关重要。我们研究了在社区中 2009 年甲型 H1N1 流感（pH1N1）传播水平较低的情况下，家庭接触者中经血清学确认的感染和疾病情况。
我们将纽约市一所高中的实验室确诊 pH1N1 感染的学生和教职员工定义为索引病例患者。在 2009 年甲型 H1N1 流感大流行的早期阶段，我们在 2009 年 5 月初和 6/7 月两次访问了索引病例患者的家庭。每次访问时，家庭接触者（包括索引病例患者和家庭接触者）都提供血清样本，并完成有关疾病和可能危险因素的调查问卷。血清学检测使用微量中和和血凝抑制试验进行。
在 28 户家庭中，有 79 名符合条件的家庭接触者，其中 19%的人血清学确认感染了 pH1N1，28%的感染者无症状。血清学确认的感染在家庭接触者中的年龄分布不同：10 岁以下的接触者中有 36%感染，10-18 岁的接触者中有 46%感染，19-54 岁的接触者中有 8%感染，55 岁及以上的接触者中有 22%感染。
确诊 pH1N1 患者的家庭接触者的感染率很高，特别是 10-18 岁的接触者，且无症状感染很常见。在流感大流行期间，减少家庭传播的努力是减少社区疾病的重要辅助手段。
