Impact of patient and provider nudges on addressing herpes zoster vaccine series completion

To determine the combined impact of provider-facing and text message-based, patient nudges on herpes zoster vaccine series completion. Following a period during which Kroger Health implemented provider facing nudges, select US patients that initiated herpes zoster vaccination were randomized to receive timed text messages when the second dose was due and available as part of a quality improvement exercise. Main comparisons were between patients intervened by provider nudge only and those intervened by both provider and patient nudges. Data were assessed by GEE-basedlogistic and linear regression, controlling for available patient- and store-level characteristics, and geospatial analyses. During the baseline period, 100,627 adults received at least one HZ vaccine dose and 83.9% completed the series within 6 months over 88.6 days (SD: 26.53) on average. In the intervention period, 120,339 adults were vaccinated at least once and series completion was 88.3% (both provider nudges and text messaging) and 85.3% (not texted) during this observation window (both p