Abstract：
BACKGROUND: Up to April 2022, there were six waves of infection of coronavirus disease 2019 (COVID-19) in Japan. As the outbreaks continue to grow, it is critical to detect COVID-19\'s clusters to allocate health resources and improve decision-making substantially. This study aimed to identify active clusters of COVID-19 in Nagasaki Prefecture and form the spatiotemporal pattern of high-risk areas in different infection periods.
METHODS: We used the prospective space-time scan statistic to detect emerging COVID-19 clusters and examine the relative risk in five consecutive periods from April 1, 2020 to April 7, 2022, in Nagasaki Prefecture.
RESULTS: The densely inhabited districts (DIDs) in Nagasaki City have remained the most affected areas since December 2020. Most of the confirmed cases in the early period of each wave had a history of travelling to other prefectures. Community-level transmissions are suggested by the quick expansion of spatial clusters from urban areas to rural areas and remote islands. Moreover, outbreaks in welfare facilities and schools may lead to an emerging cluster in Nagasaki Prefecture\'s rural areas.
CONCLUSIONS: This study gives an overall analysis of the transmission dynamics of the COVID-19 pandemic in Nagasaki Prefecture, based on the number of machi-level daily cases. Furthermore, the findings in different waves can serve as references for subsequent pandemic prevention and control. This method helps the health authorities track and investigate outbreaks of COVID-19 that are specific to these environments, especially in rural areas where healthcare resources are scarce.
METHODS: We used the prospective space-time scan statistic to detect emerging COVID-19 clusters and examine the relative risk in five consecutive periods from April 1, 2020 to April 7, 2022, in Nagasaki Prefecture.
RESULTS: The densely inhabited districts (DIDs) in Nagasaki City have remained the most affected areas since December 2020. Most of the confirmed cases in the early period of each wave had a history of travelling to other prefectures. Community-level transmissions are suggested by the quick expansion of spatial clusters from urban areas to rural areas and remote islands. Moreover, outbreaks in welfare facilities and schools may lead to an emerging cluster in Nagasaki Prefecture\'s rural areas.
CONCLUSIONS: This study gives an overall analysis of the transmission dynamics of the COVID-19 pandemic in Nagasaki Prefecture, based on the number of machi-level daily cases. Furthermore, the findings in different waves can serve as references for subsequent pandemic prevention and control. This method helps the health authorities track and investigate outbreaks of COVID-19 that are specific to these environments, especially in rural areas where healthcare resources are scarce.
摘要：
背景：截至2022年4月，日本发生了6波冠状病毒病2019（COVID-19）感染。随着疫情的持续增长，检测COVID-19的集群对于分配卫生资源和大幅改善决策至关重要。本研究旨在识别长崎县COVID-19的活跃簇，形成不同感染时期高危区域的时空格局。
方法：我们使用前瞻性时空扫描统计量检测了长崎县2020年4月1日至2022年4月7日连续五个时期的新出现的COVID-19集群，并检查了相对风险。
结果：自2020年12月以来，长崎市人口密集地区（DID）仍然是受影响最严重的地区。每波早期的大多数确诊病例都有前往其他州的历史。通过将空间集群从城市地区迅速扩展到农村地区和偏远岛屿，可以建议社区一级的传播。此外，福利设施和学校的爆发可能会导致长崎县农村地区的新兴集群。
结论：本研究对长崎县COVID-19大流行的传播动态进行了总体分析，根据机械级的每日病例数。此外，不同浪潮的发现可以为后续的大流行预防和控制提供参考。这种方法有助于卫生当局跟踪和调查这些环境特有的COVID-19疫情，尤其是在医疗资源匮乏的农村地区。
方法：我们使用前瞻性时空扫描统计量检测了长崎县2020年4月1日至2022年4月7日连续五个时期的新出现的COVID-19集群，并检查了相对风险。
结果：自2020年12月以来，长崎市人口密集地区（DID）仍然是受影响最严重的地区。每波早期的大多数确诊病例都有前往其他州的历史。通过将空间集群从城市地区迅速扩展到农村地区和偏远岛屿，可以建议社区一级的传播。此外，福利设施和学校的爆发可能会导致长崎县农村地区的新兴集群。
结论：本研究对长崎县COVID-19大流行的传播动态进行了总体分析，根据机械级的每日病例数。此外，不同浪潮的发现可以为后续的大流行预防和控制提供参考。这种方法有助于卫生当局跟踪和调查这些环境特有的COVID-19疫情，尤其是在医疗资源匮乏的农村地区。
