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标题：Transmission Network of Measles During the Yamagata Outbreak in Japan, 2017
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作者：Tetsuro Kobayashi ; Hiroshi Nishiura
期刊名称：Journal of Epidemiology
印刷版ISSN：0917-5040
电子版ISSN：1349-9092
出版年度：2022
卷号：32
期号：2
页码：96-104
DOI：10.2188/jea.JE20200455
语种：English
出版社：Japan Epidemiological Association
摘要：Background A measles outbreak involving 60 cases occurred in Yamagata, Japan in 2017. Using two different mathematical models for different datasets, we aimed to estimate measles transmissibility over time and explore any heterogeneous transmission patterns. Methods The first model relied on the temporal distribution for date of illness onset for cases, and a generation-dependent model was applied to the data. Another model focused on the transmission network. Using the illness-onset date along with the serial interval and geographical location of exposure, we reconstructed a transmission network with 19 unknown links. We then compared the number of secondary transmissions with and without clinical symptoms or laboratory findings. Results Using a generation-dependent model (assuming three generations other than the index case), the reproduction number ( R) over generations 0, 1, and 2 were 25.3, 1.3, and <0.1, respectively, explicitly yielding the transmissibility over each generation. The network data enabled us to demonstrate that both the mean and the variance for the number of secondary transmissions per primary case declined over time. Comparing primary cases with and without secondary transmission, high viral shedding was the only significant determinant ( P < 0.01). Conclusions The R declined abruptly over subsequent generations. Use of network data revealed the distribution of the number of secondary transmissions per primary case and also allowed us to identify possible secondary transmission risk factors. High viral shedding from the throat mucosa was identified as a potential predictor of secondary transmission.
关键词：Key words:enepidemictransmissibilityParamyxoviridaemathematical modelstatistical estimation