This trial is taking place in Los Angeles, CA among patients from primary care practices within the UCLA Health System, using a parallel 2-arm trial.~Sub-optimal vaccination rates are a significant problem in the U.S., despite their effectiveness in preventing morbidity and mortality from vaccine-preventable illness. In the U.S., annual epidemics of influenza cause substantial morbidity in the U.S. with up to 40,00-80,000 deaths/year and many hospitalizations, emergency and outpatient visits, and significant costs.~Young children-especially those younger than 2- are at high risk of developing serious flu-related complications. Children ages of 6 months to 8 years getting vaccinated for the first time with influenza vaccine should get two doses, and those who have only previously gotten one dose of influenza vaccine, should get a second dose (spaced at least 4 weeks apart).~Reminder/recall (R/R) messages, sent by phone, mail or other modality, can improve child vaccination rates. However, the majority of pediatric or adult primary care practices to not conduct R/R. Barriers are lack of finances, personnel, and algorithms to identify eligible patients. A technological breakthrough that might overcome these barriers involves patient portals-- secure, web-based communication systems, embedded within electronic health records (EHRs), for patients and providers to communicate with each other via email and the internet. Portals are increasingly used by healthcare systems.~This randomized controlled trial will assess the effectiveness of reminders messages, sent to the proxy of pediatric patients ages 6 months to <36 months of age eligible for a second dose of the influenza vaccine based on data in the EHR. Patients will be randomized into one of two arms to receive 1) a reminder letter for a second dose of influenza vaccine, with a direct appointment scheduling link included in the letter or 2) a reminder letter for a second dose of influenza vaccine, without a direct appointment scheduling link included in the letter.
This trial is taking place in Los Angeles, CA among patients from primary care practices within the UCLA Health System.~The study design is a parallel 2-arm trial. The parallel arms are 1) a reminder letter for the second dose of influenza vaccine (reminder messages sent via the patient portal) with a direct appointment scheduling link included in the reminder and 2) a reminder letter for the second dose of influenza vaccine, but no direct appointment scheduling link included.