Staying on track: A cluster randomized controlled trial of automated reminders aimed at increasing human papillomavirus vaccine completion

Objectives: To evaluate whether automated reminders increase on-time completion of the three-dose human papillomavirus (HPV) vaccine series. Methods: Ten reproductive health centers enrolled 365 women aged 19-26 to receive dose one of the HPV vaccine. Health centers were matched and randomized so that participants received either routine follow-up (control) or automated reminder messages for vaccine doses two and three (intervention). Intervention participants selected their preferred method of reminders - text, e-mail, phone, private Facebook message, or standard mail. We compared vaccine completion rates between groups over a period of 32 weeks. Results: The reminder system did not increase completion rates, which overall were low at 17.2% in the intervention group and 18.9% in the control group (p= 0.881). Exploratory analyses revealed that participants who completed the series on-time were more likely to be older (OR. = 1.15, 95% CI 1.01-1.31), report having completed a four-year college degree or more (age-adjusted OR. = 2.51, 95% CI 1.29-4.90), and report three or more lifetime sexual partners (age-adjusted OR. = 3.45, 95% CI 1.20-9.92). Conclusions: The study intervention did not increase HPV vaccine series completion. Despite great public health interest in HPV vaccine completion and reminder technologies, completion rates remain low.