Quadrivalent Human Papillomavirus Vaccine Uptake in Adolescent Boys and Maternal Utilization of Preventive Care and History of Sexually Transmitted Infections

Objectives. We examined whether maternal utilization of preventive care and history of sexually transmitted infections (STIs) predicted quadrivalent human papillomavirus vaccine (HPV4) uptake among adolescent boys 1 year following the recommendation for permissive use of HPV4 for males.Methods. We linked maternal information with electronic health records of 254 489 boys aged 9 to 17 years who enrolled in Kaiser Permanente Southern California health plan from October 21, 2009, through December 21, 2010. We used multivariable Poisson regression with robust error variance to examine whether HPV4 initiation was associated with maternal uptake of influenza vaccine, Papanicolaou (Pap) screening, and history of STIs.Results. We identified a modest but statistically significant association between initiation of HPV4 series and maternal receipt of influenza vaccine (rate ratio [RR] = 1.16; 95% confidence interval [CI] = 1.07, 1.26) and Pap screening (RR = 1.13; 95% CI = 1.01, 1.26). Boys whose mothers had a history of genital warts were more likely to initiate HPV4 (RR = 1.47; 95% CI = 0.93, 2.34), although the association did not reach statistical significance (P = .1).Conclusions. Maternal utilization of preventive care and history of genital warts may influence HPV4 uptake among adolescent boys. The important role of maternal health characteristics and health behaviors needs be considered in intervention efforts to increase vaccine uptake among boys.In October 2009, the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC) recommended that quadrivalent human papillomavirus vaccine (HPV4) may be given to males aged 9 to 26 years at the discretion of the patient’s health care provider (permissive use) to reduce the likelihood of acquiring genital warts (condyloma acuminata).1 However, uptake among eligible males was low following this recommendation for permissive use, with only an estimated 2% of male adolescents initiating the vaccine.2 As the national data indicated that uptake among females remained suboptimal for a few years following the recommendation for routine vaccination in females,3 human papillomavirus (HPV) vaccination of males offers an opportunity to achieve herd immunity in the whole population. On the basis of these considerations and the clinical trial data indicating HPV4’s high efficacy for prevention of genital warts and grade 2 or 3 anal intraepithelial neoplasia (AIN2/3, a precursor of anal cancer) in males, in October 2011, the ACIP recommended routine use of HPV4 in boys aged 11 or 12 years. The ACIP also recommended vaccination with HPV4 for males aged 13 through 21 years who have not been vaccinated previously or who have not completed the 3-dose series; men aged 22 through 26 years may be vaccinated.4Parents are involved in deciding whether their adolescent children get vaccinated regardless of whether the vaccine is recommended for routine use, because parental consent is typically required for adolescent HPV vaccination.5,6 Previous experience with HPV vaccination in female adolescents suggests that the decision to vaccinate their children with HPV vaccines is often affected by parents’ knowledge about HPV infection, attitudes toward the vaccine, and parental history of sexually transmitted infections (STIs) or HPV-related disease.7,8 In a previous study, we found that mothers’ Papanicolaou (Pap) screening behavior was associated with their daughters’ uptake of HPV4 in an insured population.9 Therefore, we hypothesized that previous maternal utilization of Pap screening might reflect a positive attitude toward prevention of HPV infection. In addition, mothers with a history of STIs, especially genital warts, might be familiar with preventive measures for HPV infection, which might influence their decision to vaccinate their children with HPV4 vaccine. We hypothesized that this influence might be even more important for HPV4 uptake among adolescent boys when the vaccine was initially recommended for permissive use among males in the United States.In this study, we sought to determine whether initiation of HPV4 in a large cohort of insured boys aged 9 to 17 years was associated with maternal utilization of preventive care and history of STIs during the time period when the vaccine was indicated for permissive use in males.