The mutual cyclical influence of internet information and vaccination intention on post-dissemination vaccination: A longitudinal study during the availability period of COVID-19 booster shots

The primary vaccination program for coronavirus disease 2019 (COVID-19) proceeded amid concerns about vaccine hesitancy and a plethora of internet information. However, research is lacking on the association between internet information and vaccination intention during the period when booster shots were recommended. In particular, among studies covering this timespan, there is a dearth of long-term associations between the content of internet information and its impact on beliefs and attitudes toward COVID-19 vaccines. A total of 594 Japanese adults (25–64 years old, mean age, 47.54 years, SD : 9.40) were surveyed about their intention to receive a COVID-19 vaccine. An online survey was administered at two points (February and June 2022) each lasting five days, when booster shots were available. Applying integrative health behavior theory and using structural equation modeling, we analyzed the association between factors related to beliefs, attitudes, and vaccination intention toward COVID-19 vaccines and internet information during the period when booster shots were recommended. Among content on the internet about COVID-19 vaccines, gathering information on vaccine availability for individuals increased self-efficacy, perceived benefits, and positive attitudes, which in turn enhanced vaccination intention. However, gathering information on vaccine expertise (covering both benefits and risks) negatively affected beliefs about COVID-19 vaccines. Greater vaccination intention had a cyclical effect by increasing information gathering on the internet at the next time point and influencing vaccine beliefs. The influence of internet information on attitudes toward vaccines and vaccination intention could vary, being either positive or negative depending on its content, even during the availability period of COVID-19 booster shots. Furthermore, the results suggest that information about vaccine availability should continue to be provided during booster vaccination campaigns. Finally, we discuss ways of using the internet to disseminate information appropriately and effectively in order to promote vaccination. Clinical trial registration • Booster vaccination in Japan, with high hesitancy, was influenced differently by internet information. • The vaccination intention positively correlated with information on the availability of the vaccines. • Intention negatively correlated with information on vaccine expertise covering both benefits and risks. • Internet information gathering showed a long-term mutual cycle with vaccine beliefs and intentions.