Raw data of COVID-19 patient in Busan Port.

Quarantine played an important role in preventing the spread of infectious diseases between countries in the early stages of the COVID-19 outbreak. In particular, in ports, infection during transit can cause a large number of patients on board ships and can flow into the community. In this study investigated cause of the cause of transmission in ships and suggested the way of preventing secondary transmission by analyzing clinical and epidemiological characteristics of COVID-19 patients identified at Busan Port (South Korea) in 2020. During the study period, out of 19,396 ships that arrived at Busan Port, 50 ships had COVID-19 confirmed cases. Among the 50 ships, type of deep-sea fishing vessels (24 ships, 48.0%), ships weighing less than 5,000 tons (31 ships, 62.0%), and ships from Russia (41 ships, 82.0%) had the highest positivity rates. Total 283 of the 25,450 arrivals tested positive for COVID-19 (a positivity rate of 1.1%), and 270 (95.4%) were asymptomatic. Moreover, the number of COVID-19 patients increased with the duration of the waiting period between arrival and sample collection (12.7% to 37.4%), and the positivity rate was significantly higher for those working as stewards (64.3%). These results indicate secondary transmission was active on board ships and that infection among stewards importantly contributed to group outbreaks. In addition, onboard residence time after arrival significantly elevated to COVID-19 positivity rates, indicating that rapid isolation, as determined using various screening techniques, might be effective at preventing onboard transmission and subsequent community outbreaks.在新冠疫情（COVID-19）暴发初期，检疫在阻止传染病跨国传播方面发挥了重要作用。尤其在港口区域，转运过程中的感染可能导致船舶上出现大量感染者，并进而流入周边社区。本研究通过分析2020年在韩国釜山港（Busan Port）检出的新冠患者的临床与流行病学特征，探究了船舶上的传播成因，并提出了预防二次传播的策略。研究期间，在抵达釜山港的19396艘船舶中，共有50艘船上检出新冠确诊病例。在这50艘涉疫船舶中，深海渔船（24艘，占比48.0%）、载重不足5000吨的船舶（31艘，占比62.0%）以及来自俄罗斯的船舶（41艘，占比82.0%）的阳性检出率最高。在25450名抵港人员中，共有283人新冠检测呈阳性，阳性率为1.1%，其中270人（占比95.4%）为无症状感染者。此外，新冠感染者数量随抵港至采样的等待时长增加而上升，阳性率从12.7%升至37.4%；且船舶乘务员（stewards）的阳性检出率显著更高，达64.3%。上述结果表明，船舶上存在活跃的二次传播，且乘务员群体的感染是导致聚集性暴发的重要诱因。此外，抵港后的船上滞留时长与新冠阳性检出率呈显著正相关，提示通过各类筛查技术实现快速隔离，或可有效阻断船舶内传播及后续的社区暴发疫情。