ABSTRACT
BACKGROUND: The epidemiology and risk of coronavirus disease 2019 (COVID-19) among travelers at international borders remain unclear. METHODS: We conducted descriptive and individually matched case-control studies using a nationwide register for COVID-19 testing of travelers from 3 August to 31 October 2020 at airport/port quarantine stations across Japan. Case patients, defined as travelers positive for COVID-19 on arrival, were individually matched with 4 controls for arrival date and airport or port. We assessed associations between test positivity and traveler characteristics using conditional logistic regression analysis. RESULTS: Overall, 157 507 travelers arriving from 146 countries/areas at 17 quarantine stations across Japan were tested for COVID-19. The percentage of test positivity during the study period was 0.35%. In the case-control study, with 536 case patients and 2144 controls, we found evidence of lower test positivity in travelers aged 3-19 years, female travelers, and travel corridor users (adjusted odds ratio [95% confidence interval], 0.36 [.22-.60], 0.71 [.56-.89], and 0.48 [.30-.77], respectively), whereas higher positivity was associated with arrival from South-East Asia (1.88 [1.33-2.65]) or lower-middle- or low-income countries (2.46 [1.69-3.58] and 7.25 [2.22-23.66], respectively), any symptom (4.08 [1.43-11.65]), and nasopharyngeal compared with saliva sampling (2.75 [1.85-4.09]). A higher 14-day average incidence in the countries of stay was also associated with higher test positivity (1.64 [1.16-2.33] and 3.13 [1.88-5.23] for those from countries and areas where the 14-day average incidence was from 10 to <100 and ≥100 cases per million, respectively). CONCLUSIONS: These findings justify travel restrictions based on the epidemic situation in countries of stay, although underestimation of the epidemic in lower-income countries should be considered. A strict travel corridor could also reduce the risk of COVID-19 importation.
Subject(s)
COVID-19 , Airports , COVID-19/epidemiology , COVID-19 Testing , Case-Control Studies , Female , Hospitals, Isolation , Humans , Japan/epidemiology , Quarantine , TravelABSTRACT
The outbreak of coronavirus disease 2019 (COVID-19) on the cruise ship Diamond Princess docked at Yokohama, Japan was highlighted due to its number of cases in the early stage of the global epidemic when the picture of the virus itself, as well as epidemiological characteristics, were being established. We conducted an observational epidemiological study of the outbreak, focusing on a total of 403 individuals who developed a fever of ≥ 37.5°C from 20 January to 22 February 2020. Quarantine measures are also discussed with a descriptive method. Of a total of 3,711 individuals (2,031 males) from 57 countries, 2,666 (71.8%) and 1,045 (28.2%) were passengers and crew with mean age of 66.0 (range: 2-98) and 36.6 (range: 19-64), respectively. Among 403 febrile individuals, 165 passengers and 58 crew members were diagnosed as laboratory-confirmed COVID-19 cases. Until 6 February, the number of confirmed cases was three or less per day. However, distribution of thermometers on 7 February revealed 43 confirmed cases, and it then started decreasing. The outbreak was initiated from decks for passengers and expanded to areas for crew. As of 17 March, when more than14 days had passed after disembarkation of all passengers and crew, there was no report of forming a cluster of infections in Japan from them. At the time of the initiation of quarantine, the outbreak had already expanded to most of the decks from those for passengers, and the results might suggest the contribution of the set of quarantine measures in unprecedented challenges of the control operation.
ABSTRACT
Due to the significant spread of a new type of coronavirus (SARS-CoV-2) infection (COVID-19) in China, the Chinese government blockaded several cities in Hubei Province. Japanese citizens lost a means of transportation to return back to Japan. The National Center for Global Health and Medicine (NCGM) helped the operation of charter flights for evacuation of Japanese residents from Hubei Province, and this article outlines our experiences. A total of five charter flights were dispatched, and the majority of returnees (793/829 [95.7%]) were handled at NCGM. A large number of personnel from various departments participated in this operation; 107 physicians, 115 nurses, 110 clerical staff, and 45 laboratory technicians in total. Several medical translators were also involved. In this operation, we conducted airborne precautions in addition to contact precautions. Eye shields were also used. The doctors collecting the pharyngeal swab used a coverall to minimize the risk of body surface contamination from secretions and droplets. Enhanced hand hygiene using alcohol hand sanitizer was performed. Forty-eight persons were ultimately hospitalized after the triage at NCGM operation, which was more than the number of persons triaged at the airport (n = 34). Of those hospitalized after NCGM triage, 8.3% (4/48 patients) ultimately tested positive for SARS-CoV-2, significantly higher than the positive rate among subjects not triaged (4/48 [8.3%] vs. 9/745 [1.2%]: p = 0.0057). NCGM participated in a large-scale operation to evacuate Japanese nationals from the COVID-19 epidemic area. We were able to establish a scheme through this experience that can be used in the future.