Epidemiology and Risk of Coronavirus Disease 2019 Among Travelers at Airport and Port Quarantine Stations Across Japan: A Nationwide Descriptive Analysis and an Individually Matched Case-Control Study

Abstract

Background The epidemiology and risk of 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 August 3 to October 31, 2020 at airport/port quarantine stations across Japan. Cases defined as COVID-19-positive travelers on arrival were individually matched with four controls for arrival date and airport/port. We assessed associations between test positivity and traveler characteristics using conditional logistic regression. Results Overall, 157,507 travelers arriving from 146 countries/areas at 17 quarantine stations across Japan were tested for COVID-19. The test percent positivity during the study period was 0.35%. In the case-control study with 536 cases and 2,144 controls, we found evidence of lower test positivity in travelers aged 3–19 years, females, and travel corridor users (adjusted odds ratio [95% confidence interval]: 0.36 [0.22–0.60], 0.71 [0.56–0.89], and 0.48 [0.30–0.77], 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 to 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]). 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 COVID-19 importation risk.

Global border restrictions in 2020–2021: Adherence and the effectiveness in long-term COVID-19 epidemic control

“…As the results, inbound quarantine were identified as effective policies in mitigating severe epidemics. Besides, the policy of ban on regions was demonstrated with the ineffective and potentially facilitating role in long-term epidemic progression, which contradicted to the results in previous studies [ [47] , [48] , [49] ]. Such findings revealed the difference of border policy effectiveness between in short-term and long-term applications, and may help improve decision-making on long-term border strategies against COVID-19 and other emerging global health threats.…”

“…S6 ). One possible reason is that in the initial stage of pandemic, the epicenters were restricted to certain countries, and such implementation may be more effective than in latter time [ [47] , [48] , [49] ].…”

Effectiveness of Point of Entry Health Screening Measures among Travelers in the Detection and Containment of the International Spread of COVID-19: A Review of the Evidence

“…Twenty observational studies reported on screening strategies used at POEs for the detection of COVID-19, as shown in Table 2. Testing of travelers was reported by 14 of the included studies [17][18][19][20][21][22][23][24][25][26][27][28][29][30], Sign and symptom assessment, especially loss of taste or smell, myalgia, cough, shortness of breath, self-reported fever, chills and vomiting, were reported by 10 out of 20 studies [20,21,27,28,[30][31][32][33][34][35], followed by body temperature checks in seven studies [20,24,31,[33][34][35][36] and exposure assessment by six other studies [20,21,27,30,32,35]. Three studies reported on the daily telephone calls of travelers after arrival for 14 days [20], checking vaccination status [22] and inspection of RT-PCR test certificates [27].…”

As Omicron Takes Hold and Other New Variants Arise, COVID-19 Testing Remains the Universally Agreed Tool to Effect Transition From Pandemic to Endemic State

“…Testing of travelers from regions where there is increased disease prevalence or variants of interest/concern can potentially reduce transmission (17). In addition, travel testing can monitor global disease prevalence and assess geographic and longitudinal trends (18).…”