On December 22, the Central Epidemic Command Center (CECC) reported that the spread of coronavirus disease 2019 (COVID-19) accelerated in the United Kingdom recently, which has become worse with a mutant strain of the virus first detected in September in the country. The UK authorities pointed out that the new strain can be up to 70% more transmissible than the original strain.

To avoid adverse impacts caused by the developments, the CECC announced that the number of passenger flights flying between Taipei and London would be decreased by half, effective from 00:00 am on December 23, and all of the flights would be operated by China Airlines this week (flights operated by EVA Air this week have been cancelled). The Civil Aeronautics Administration will coordinate the subsequent flights operated by the two airlines alternately for the following weeks. Furthermore, travelers arriving in Taiwan from the United Kingdom and those who have traveled to the United Kingdom in the past 14 days are required to proceed to group quarantine facilities to undergo quarantine for 14 days after entry. Before they complete the quarantine period, they will be tested for COVID-19. Additionally, flight crew and cabin crew members are also required to undergo home quarantine for 14 days; before they complete the home quarantine period, they will be tested for COVID-19, and they are allowed to enter the community after obtaining a negative test result and conducting the 7-day self-health management. If dormitories of airline companies can't follow related management measures, such flight crew and cabin crew members shall stay at quarantine hotels for quarantine.