Objective To evaluate the effectiveness of information interventions based on the social processes framework in promoting influenza vaccination acceptance among adults aged 18 years and older, and to explore the factors influencing the effectiveness of these interventions.

Methods Between January 29 and February 4, 2021, an online survey was conducted among 3 345 adults aged 18 years and above in Guichi district, Chizhou city; Yuhuatai district, Nanjing city; and Changning district, Shanghai city. The survey collected data on sociodemographic characteristics, self-rated health status, perceived susceptibility to and severity of influenza, influenza vaccine awareness, and influenza vaccination history for the 2019–2020 and 2020–2021 influenza seasons. Participants were also exposed to an embedded, framework-based intervention containing information about influenza, and their intention to receive influenza vaccine in the next season was measured both before and after the intervention. McNemar-Bower tests and binary logistic regression were used to analyze the intervention′s effect and its factors.

Results Of the 3 345 participants, 89.30% rated their health as good; 15.81% perceived high susceptibility to influenza; 64.16% perceived influenza as a serious threat; 55.46% reported awareness of influenza vaccines; and 15.67% reported having received an influenza vaccine in the past two seasons. At the individual level, there was a statistically significant difference in the distribution of vaccination intentions before and after the intervention (P<0.01). At the population level, the proportion of adult participants willing to be vaccinated in the next influenza season increased from 40.93% to 63.38% after the intervention. Binary logistic stepwise regression analysis showed that residing in Chizhou city, being female, having an annual household income of 60 000 RMB or above, lower perceived susceptibility to influenza, lower influenza vaccine awareness, and no history of influenza vaccination were associated with increased acceptance to receive influenza vaccines after the intervention (P<0.05).

Conclusions Information interventions based on the social processes framework can significantly improve influenza vaccination acceptance among adults. City of residence, sex, annual household income, perceived susceptibility to influenza, influenza vaccine awareness, and influenza vaccination history are factors influencing the effectiveness of these interventions.