BACKGROUND Social contact surveys can greatly help in quantifying the heterogeneous patterns of infectious disease transmission. The present study aimed to conduct a contact survey in Japan, offering estimates of contact by age and location and validating a social contact matrix using a seroepidemiological dataset of influenza. METHODS An internet-based questionnaire survey was conducted, covering all 47 prefectures in Japan and including a total of 1476 households. The social contact matrix was quantified assuming reciprocity and using the maximum likelihood method. By imposing several parametric assumptions for the next-generation matrix, the empirical seroepidemiological data of influenza A (H1N1) 2009 was analysed and we estimated the basic reproduction number, R0. RESULTS In total, the reported number of contacts on weekdays was 10,682 whereas that on weekend days was 8867. Strong age-dependent assortativity was identified. Forty percent of weekday contacts took place at schools or workplaces, but that declined to 14% on weekends. Accounting for the age-dependent heterogeneity with the known social contact matrix, the minimum value of the Akaike information criterion was obtained and R0 was estimated at 1.45 (95% confidence interval: 1.42, 1.49). CONCLUSIONS Survey datasets will be useful for parameterizing the heterogeneous transmission model of various directly transmitted infectious diseases in Japan. Age-dependent assortativity, especially among children, along with numerous contacts in school settings on weekdays implies the potential effectiveness of school closure.

中文翻译：

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量化日本的异质接触模式：社会接触调查。

背景技术社会接触调查可以极大地帮助量化传染病传播的异质模式。本研究旨在在日本进行接触调查，按年龄和地点提供接触估计，并使用流感血清流行病学数据集验证社会接触矩阵。方法采用网络问卷调查，覆盖日本全部47个都道府县，共1476户家庭。假设互惠并使用最大似然法对社会接触矩阵进行量化。通过对下一代矩阵施加多个参数假设，分析了 2009 年甲型 H1N1 流感的经验血清流行病学数据，并估计了基本繁殖数 R0。结果 报告的工作日接触人数总计为 10,682 人，而周末接触人数为 8867 人。发现了强烈的年龄依赖性分类性。工作日 40% 的接触发生在学校或工作场所，但周末这一比例下降至 14%。考虑到已知社会接触矩阵的年龄依赖性异质性，获得了 Akaike 信息标准的最小值，R0 估计为 1.45（95% 置信区间：1.42、1.49）。结论 调查数据集将有助于参数化日本各种直接传播传染病的异质传播模型。年龄相关的分类性，尤其是儿童之间的分类性，以及工作日在学校环境中的大量接触，意味着学校关闭的潜在效果。