The survey was sent out from June 24 th to June 30 th , 2009 when the WHO influenza pandemic alert level assigned to H1N1 was phase 6. Phase 6 signifies a widespread human infection, indicating that the virus has caused sustained community level outbreaks in at least one other country in another WHO region (WHO pandemic phase description). The pandemic in Hong Kong started on 1 st May, when a Mexican traveller was confirmed with influenza A (H1N1). Till the end of our data collection, there were 1389 confirmed cases and no death were reported.