Each unwell passenger and crew member was screened for infl uenza-like illness by a nurse and assessed by a medical offi cer if illness met the defi nition of a suspected case. Those whose illness met the case defi nition had nasopharyngeal swabs taken, were offered oseltamivir, and were sent home or to a facility for isolation. Reverse transcription PCR (RT-PCR) was used to confi rm infection. Screening was escalated on April 29 to include all passengers arriving from other countries and stopped on June 22.