Outcome measures
SECONDARY, PCP, FLU, INFLUENZA
We evaluated two sets of outcomes. The primary outcomes were changes in the numbers of vaccinated older patients in the 24 studied health centres during the 2016–2017 flu season (pre-intervention of PCP recommendation: October 1, 2016 to April 30, 2017) and the 2017–2018 flu season (post-intervention of PCP recommendation: October 1, 2017 to April 30, 2018). The vaccination data were collected form the vaccination information record. The secondary outcomes were the older participants’ (1) knowledge of, attitude towards influenza vaccination; (2) vaccination status and reasons for not taking vaccination, which were collected from our self-designed questionnaire.