SARS-CoV-2 Infection Risk Imposed by Fully-vaccinated Air Travelers Attending an Island-confined Quarantine System Enabling Tourism During the Pandemic: A Retrospective Cohort Study.

Objectives: This study aimed to identify the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among fully vaccinated air travelers participating in an island-confined quarantine system (Phuket Sandbox Program). It also compared the differential risk of SARS-CoV-2 infection across different coronavirus disease 2019 (COVID-19) vaccines and the difference in time-to-detection periods between asymptomatic and symptomatic cases.

Methods: This retrospective cohort study determined the cumulative incidence of SARS-CoV-2 infection among 63 052 air travelers who participated in a quarantine program from July 1, 2021 to October 31, 2021.