On September 2, the Central Epidemic Command Center (CECC) announced that the Vietnamese and Japanese authorities each had sent a notification to Taiwan through the International Health Regulations (IHR) National Focal Point that an asymptomatic traveler had tested positive for coronavirus disease 2019 (COVID-19) after the traveler's departure from Taiwan.

The CECC stated that the case reported by the Vietnamese authorities is a female migrant worker in her 30s. The female migrant worker returned to Vietnam from Taiwan on August 7. She was tested for COVID-19 upon entry into Vietnam and took another test on August 14. Her two test results all came back negative. The female migrant worker took the third test on August 26, and she tested positive. The CECC preliminarily deduced that the case was less likely to contract the disease in Taiwan. The health authorities have identified the individuals who had come into contact with the female migrant worker in Taiwan and have tested them. Those contacts all tested negative.

Regarding the case reported by the Japanese authorities, the case is a Taiwanese male in his 50s. The case returned to Taiwan from Japan on March 19. He traveled to Japan with his friends on August 31. The male case was tested for COVID-19 upon entry into Japan, and he tested positive. However, his friends he traveled with tested negative. Taiwan's health authorities have identified and tested one individual who came into contact with the case in Taiwan, and the contact is awaiting test result. The CECC will continue to investigate the case and conducts contact tracing.