Effectiveness of a digital communication and active recall strategy to improve pediatric influenza vaccination in primary care: a prospective observational study

Background: Influenza remains a significant health problem in early childhood, with vaccination uptake still below optimal levels. This study assessed the effectiveness of a combined digital and active reminder intervention in promoting influenza vaccination among children aged 6 months to 6 years. Methods: A prospective observational study enrolled 792 eligible children, aged 6 months to 6 years, in a pediatric primary care practice within the Italian National Health Service, Local Health Unit Bari (LHU BA). Parents received web-based informational content about influenza vaccination and personalized vaccination reminders. Vaccination coverage, uncomplicated Influenza-Like Illnesses (ILI), and confirmed influenza cases were monitored. Results: Out of 792 eligible children, 375 (47.4%) adhered to the campaign; 358 (95.5%) completed the full vaccination schedule. 17 children were partially vaccinated with the intramuscular vaccine due to lack of doses. Intramuscular vaccine was administered to 281 children (74.9%), and intranasal to 94 (25.1%). Vaccination coverage was significantly higher than both the local health district (LHU BA, 33.1%) and the regional one (Puglia, 29.7%) (p < 0.001). A total of 259 ILI episodes were registered: 94 among fully vaccinated children, 160 among unvaccinated children, and 5 in partially vaccinated children. 169 rapid flu tests were performed: 75 in fully vaccinated, 89 in unvaccinated, and 5 in partially vaccinated children. Influenza was confirmed in 7 fully vaccinated children (1 intranasal, 6 intramuscular), 41 unvaccinated, and 4 partially vaccinated children. Vaccination was significantly associated with lower odds of influenza (OR = 0.15; 95% CI: 0.06-0.36; p < 0.001), corresponding to a vaccine effectiveness of 85%. Conclusions: The intervention improved vaccination coverage compared to regional and local benchmarks. Vaccinated children showed both a lower incidence of ILI and confirmed influenza cases, supporting the potential of digital strategies in enhancing pediatric flu vaccination programs.