2009 年甲型 H1N1 流感大流行在英格兰的感染发病率：一项横断面血清学研究。

Incidence of 2009 pandemic influenza A H1N1 infection in England: a cross-sectional serological study.

机构信息

Immunisation, Hepatitis and Blood Safety Department, Health Protection Agency Centre for Infections, London, UK.

出版信息

Lancet. 2010 Mar 27;375(9720):1100-8. doi: 10.1016/S0140-6736(09)62126-7. Epub 2010 Jan 21.

DOI:10.1016/S0140-6736(09)62126-7

PMID:20096450

Abstract

BACKGROUND

Knowledge of the age-specific prevalence of immunity from, and incidence of infection with, 2009 pandemic influenza A H1N1 virus is essential for modelling the future burden of disease and the effectiveness of interventions such as vaccination.

METHODS

In this cross-sectional serological survey, we obtained 1403 serum samples taken in 2008 (before the first wave of H1N1 infection) and 1954 serum samples taken in August and September, 2009 (after the first wave of infection) as part of the annual collection for the Health Protection Agency seroepidemiology programme from patients accessing health care in England. Antibody titres were measured by use of haemagglutination inhibition and microneutralisation assays. We calculated the proportion of samples with antibodies to pandemic H1N1 virus in 2008 by age group and compared the proportion of samples with haemagglutination inhibition titre 1:32 or more (deemed a protective response) before the first wave of infection with the proportion after the first wave.

FINDINGS

In the baseline serum samples from 2008, haemagglutination inhibition and microneutralisation antibody titres increased significantly with age (F test p<0.0001). The proportion of samples with haemagglutination inhibition titre 1:32 or more ranged from 1.8% (three of 171; 95% CI 0.6-5.0) in children aged 0-4 years to 31.3% (52 of 166; 24.8-38.7) in adults aged 80 years or older. In London and the West Midlands, the difference in the proportion of samples with haemagglutination inhibition titre equal to or above 1:32 between baseline and September, 2009, was 21.3% (95% CI 8.8-40.3) for children younger than 5 years of age, 42.0% (26.3-58.2) for 5-14-year-olds, and 20.6% (1.6-42.4) for 15-24-year-olds, with no difference between baseline and September in older age groups. In other regions, only children younger than 15 years showed a significant increase from baseline (6.3%, 1.8-12.9).

INTERPRETATION

Around one child in every three was infected with 2009 pandemic H1N1 in the first wave of infection in regions with a high incidence, ten times more than estimated from clinical surveillance. Pre-existing antibody in older age groups protects against infection. Children have an important role in transmission of influenza and would be a key target group for vaccination both for their protection and for the protection of others through herd immunity.

FUNDING

National Institute for Health Research Health Technology Assessment Programme.

摘要

背景

了解特定年龄人群对 2009 年甲型 H1N1 流感的免疫和感染的发生率，对于预测疾病的未来负担以及评估疫苗等干预措施的效果至关重要。

方法

本横断面血清学调查于 2008 年（甲型 H1N1 首次感染浪潮之前）和 2009 年 8 月至 9 月（首次感染浪潮之后）采集了共 1403 份血清样本和 1954 份血清样本，这些样本来自英格兰各地就诊患者，是英国卫生保护局血清流行病学计划年度采集的一部分。采用血凝抑制和微量中和试验测定抗体滴度。我们按年龄组计算了 2008 年具有大流行 H1N1 病毒抗体的样本比例，并比较了首次感染浪潮前具有血凝抑制滴度 1：32 或更高（被认为是保护性反应）的样本比例与首次感染浪潮后的比例。

结果

在 2008 年的基线血清样本中，血凝抑制和微量中和抗体滴度随年龄增长而显著增加（F 检验 p<0.0001）。具有血凝抑制滴度 1：32 或更高的样本比例范围为 0-4 岁儿童为 1.8%（171 例中 3 例；95%CI 0.6-5.0），80 岁及以上的成年人为 31.3%（166 例中 52 例；24.8-38.7）。在伦敦和西米德兰兹郡，5 岁以下儿童的血凝抑制滴度等于或高于 1：32 的样本比例在基线和 2009 年 9 月之间的差异为 21.3%（95%CI 8.8-40.3），5-14 岁儿童为 42.0%（26.3-58.2），15-24 岁儿童为 20.6%（1.6-42.4），而年龄较大的组在基线和 9 月之间没有差异。在其他地区，只有 15 岁以下的儿童的感染率与基线相比有显著增加（6.3%，1.8-12.9）。