Using the Health Action Process Approach and implementation intentions to increase flu vaccine uptake in high risk...

Influenza vaccination rates remain suboptimal in many countries, including Thailand. This study compared the effect of a theory-based educational leaflet, based on the Health Action Process Approach (HAPA), and action planning intervention with a standard government information leaflet designed to increase influenza vaccination uptake among high-risk Thai adults.

A controlled before and after trial was conducted. Participants in the intervention (n = 99) received a leaflet based on the HAPA and asking them to form an action plan identifying where, when, and how they would seek vaccination. Those in the comparison condition (n = 102) received a standard government information leaflet.

There are 2 sets of outcome measures: (a) process measures of HAPA related variables taken at T1 and T2, and (b) vaccination rates during the subsequent 2 months.

The HAPA intervention resulted in greater changes on measures of risk perception, outcome expectancies, self-efficacy, and intention than the comparison condition. Stronger intentions to obtain vaccination were explained by changes in outcome expectancies, perceived self-efficacy for arranging time and transportation, and planning. No significant difference in vaccination rates was observed between two groups. Influenza vaccination was directly predicted by self-efficacy and intention.

Results demonstrate that a HAPA-based leaflet may be a useful tool to enhance individual's vaccination intention, but larger trials are required to confirm these findings.