From November 2009 onwards, television, radio, newspaper and official websites strongly encouraged priority groups to have pH1N1 vaccination [13] . However, the Hong Kong government did not make recommendations for the general population, who were asked to judge for themselves whether to be vaccinated or not. Shortly after the vaccine launch for priority groups, local media prominently attributed several adverse events to pH1N1 vaccination, including, a case of Guillain-Barre Syndrome (GBS) diagnosed a week after pH1N1 vaccination, reported on 6th January 2010, and an intrauterine death (IUD) 3 weeks following the mother's vaccination, reported on 20th January 2010 ( Figure 2 ). In both cases local health agencies presented convincing evidence challenging the link between vaccination and the two adverse events but were largely ignored. Retrospectively, a drop in pH1N1 vaccination uptake among priority groups was observed [14] . It seems probable that the adverse media reports had impeded vaccination uptake among general population. We collected baseline data between 12-25 January, 2010, immediately before pH1N1 vaccine was made available to the general population and then two months later (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) March 2010) we recorded their reported vaccination status ( Figure 2 ) with the intention of modelling how general population decision-making regarding pH1N1 vaccination might predict subsequent vaccine uptake.