Forest plot shows adjusted RR with two-sided 95% CI comparing HPV vaccine receipt or scheduled appointment between chatbot and usual care groups in each subgroup. The data present estimates from ITT analyses using stratified GEE models, with class as the cluster unit. The models adjusted for stratification variables and confounders including parents characteristics (age, education level, employment, income, self or spouse HPV vaccination) and daughters characteristics (age, only child, left-behind child, sexual education, influenza vaccination). No estimate was provided for the Daughter left-behindYes subgroup owing to zero events in the usual care group. Statistical significance was set at P < 0.05 (two-tailed). CNY, Chinese Yuan.
