Interventions to increase influenza vaccination rates in children with high-risk conditions-A systematic review

Background: Influenza is a common cause of morbidity and mortality, especially among the elderly and those with certain chronic diseases. Annual influenza vaccination is recommended for individuals in at-risk groups, but rates of vaccination are particularly low in children with high-risk conditions (HRCs). Objective: To conduct a systematic review of studies that have examined interventions aimed at improving influenza vaccination in children with HRCs. Methods: Two databases - PubMed and SCOPUS - were searched (with no time or language restrictions) using a combination of keywords - Influenza AND vaccination OR immunization OR children AND asthma OR malignancy OR high-risk AND reminder. Duplicates were removed, and abstracts of relevant articles were screened using specific inclusion/exclusion criteria. Thirteen articles were selected, and five additional studies were identified following a review of the reference lists of the initial thirteen articles, bringing the total number to eighteen. Results: Most studies were conducted in the United States. Among the 18 studies, there was one systematic review of a specific intervention in asthmatic children, seven randomized controlled trials (RCTs), six before-and-after studies, one non-randomized controlled trial, one retrospective cohort study, one quasi-experimental post-test study, and one letter to editors. Interventions reported include multi-component strategies, letter reminders, telephone recall, letters plus telephone calls, an asthma education tool and year-round scheduling for influenza vaccination, amongst others. Conclusion: There is good evidence that reminder letters will improve influenza vaccination uptake in children with HRCs, but the evidence that telephone recall or a combination of letter reminder and telephone recall will improve uptake is weak. It is not known if multiple reminder letters are more effective than single letters or if multi-component strategies are more effective than single or dual component strategies. There is a need for further research of these interventions, possibly outside the United States.