The study is to be conducted over the 1st season (September 2024-April 2025) as an effectiveness trial and the 2nd (September 2025-April 2026) as a replication study. This protocol covers the first season. Parents of eligible children who are 6 month-17 year-old who are due for both a COVID-19 and influenza vaccine will be sent text messages. Within each practice site, parents of eligible children will be randomized to receive either: 1) combined COVID-19 and influenza vaccine text message reminders, 2) COVID-19 reminders alone, 3) influenza reminders alone, or 4) no reminders (usual care).
Randomization is to be stratified by practice site, age group and prior year's COVID-19/influenza vaccine history. Messages will be sent centrally and managed by the research team.
