title: A randomized intervention of reminder letter for human papillomavirus vaccine series completion.
abstract: OBJECTIVE
  Completion rate for the three-dose series of the human papillomavirus (HPV) vaccine has generally been low. This study evaluated the effectiveness of a reminder letter intervention on HPV vaccine three-dose series completion.
  
  
  METHODS
  Female members of Kaiser Permanente Southern California Health Plan who received at least one dose, but not more than two doses, of the HPV vaccine by February 13, 2013, and who were between ages 9 and 26 years at the time of first HPV vaccination were included. Eighty percent of these females were randomized to receive the reminder letter, and 20% were randomized to receive standard of care (control). The reminder letters were mailed quarterly to those who had not completed the series. The proportion of series completion at the end of the 12-month evaluation period was compared using chi-square test.
  
  
  RESULTS
  A total of 9,760 females were included in the intervention group and 2,445 in the control group. HPV vaccine series completion was 56.4% in the intervention group and 46.6% in the control groups (p < .001). The effect of the intervention appeared to be stronger in girls aged 9-17 years compared with young women aged 18-26 years at the first dose and in blacks compared with whites.
  
  
  CONCLUSIONS
  Reminder letters scheduled quarterly were effective to enhance HPV vaccine series completion among those who initiated the vaccine. However, a large gap in series completion remained despite the intervention. Future studies should address other barriers to series completion, including those at the providers and the health care system level.
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California. Electronic address: chun.r.chao@kp.org.
authors.forename: Chun
authors.initials: C
authors.lastname: Chao
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California.
authors.forename: Melissa
authors.initials: M
authors.lastname: Preciado
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California.
authors.forename: Jeff
authors.initials: J
authors.lastname: Slezak
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California.
authors.forename: Lanfang
authors.initials: L
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D002140:California; D002648:Child; D015709:Correspondence as Topic; D005260:Female; D058015:Health Communication / Q000379:methods*; D006293:Health Promotion / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D030361:Papillomavirus Infections / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000008:administration & dosage*; D010349:Patient Compliance / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D053918:Papillomavirus Vaccines
keywords: Adherence; Human papillomavirus; Human papillomavirus vaccine; Intervention