Analysis of Imported Cases of COVID-19 in Taiwan: A Nationwide Study

Int J Environ Res Public Health. 2020 May 9;17(9):3311. doi: 10.3390/ijerph17093311.


In the early stages of the 2019 novel coronavirus disease (COVID-19) pandemic, containment of disease importation from epidemic areas was essential for outbreak control. This study is based on publicly accessible data on confirmed COVID-19 cases in Taiwan extracted from the Taiwan Centers for Disease Control website. We analysed the characteristics, infection source, symptom presentation, and route of identification of the 321 imported cases that were identified from 21 January to 6 April 2020. They were mostly returned Taiwanese citizens who had travelled to one or more of 37 countries for tourism, business, work, or study. Half of these cases developed symptoms before arrival, most of the remainder developed symptoms 1-13 days (mean 4.0 days) after arrival, and 3.4% never developed symptoms. Three-quarters of the cases had respiratory symptoms, 44.9% had fever, 13.1% lost smell or taste, and 7.2% had diarrhoea. Body temperature and symptom screening at airports identified 32.7% of the cases. Of the remainder, 27.7% were identified during home quarantining, 16.2% were identified via contact tracing, and 23.4% were reported by hospitals. Under the strict enforcement of these measures, the incidence of locally acquired COVID-19 cases in Taiwan remains sporadic. In conclusion, proactive border control measures are effective for preventing community transmission of this disease.

Keywords: 2019 novel coronavirus diseases (COVID-19); border control; contact tracing; imported cases; isolation; pandemic outbreak; quarantine; reproduction number; symptom.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Airports
  • Asymptomatic Infections
  • Betacoronavirus
  • COVID-19
  • Contact Tracing*
  • Coronavirus / isolation & purification*
  • Coronavirus Infections* / diagnosis
  • Coronavirus Infections* / epidemiology
  • Coronavirus Infections* / transmission
  • Disease Outbreaks / prevention & control
  • Disease Transmission, Infectious / prevention & control*
  • Fever of Unknown Origin / diagnosis*
  • Humans
  • Incidence
  • Mass Screening / methods*
  • Pandemics / prevention & control
  • Pneumonia, Viral* / diagnosis
  • Pneumonia, Viral* / epidemiology
  • Pneumonia, Viral* / transmission
  • Population Surveillance
  • Quarantine
  • SARS-CoV-2
  • Sentinel Surveillance
  • Social Isolation
  • Taiwan / epidemiology
  • Travel Medicine
  • Travel*