HPV vaccine program for grade 6 boys in BC starting September 2017

In January 2017 the BC Minister of Health announced the approval of publicly funded human papilloma virus (HPV) vaccine for boys. The program will start in the 2017–18 school year and all grade 6 boys will be eligible. This program will run in conjunction with the HPV vaccine offered for grade 6 girls, who have been eligible since September 2008. While these programs are largely delivered in school-based clinics by public health nurses throughout the province, many studies have shown that a recommendation from a trusted health care provider, including a family doctor or pediatrician, is strongly associated with the decision to vaccinate. Uptake of HPV vaccine for grade 6 girls remains lower than for other school-based immunization programs.

The inclusion of boys in the routine grade 6 program provides an opportunity for physicians to stress the importance of this vaccine for both genders, answer any questions that parents or kids may have, and give their recommendation in support of vaccination.

The vaccine that will be used in the BC program is the 9-valent HPV vaccine (HPV9 or Gardasil 9, Merck Canada Inc.),[1] which was introduced into the program for girls in September 2016 and has replaced the use of the 4-valent vaccine for all aspects of the BC program, including the high-risk male program.[2] This vaccine is currently approved for use by Health Canada for boys and men age 9 to 26 years for prevention of anogenital warts, anal cancer, and precancerous lesions.[3,4] As for girls, a schedule of only two doses given 6 months apart is approved for use in boys who start a series prior to 15 years of age, based on a noninferior immune response to two doses in this age group compared to three doses in older cohorts in whom clinical endpoints were also assessed for efficacy. Clinical trials of HPV 4-valent vaccine in 16- to 26-year-old females and males, as well as men who have sex with men, and of HPV9 in females, have demonstrated high efficacy. HPV9 efficacy has been comparable to that of HPV4 for the same four strains (types 6 and 11 causing genital warts, and types 16 and 18 causing the majority of cancers) of the virus for infection, persistent infection, and precancerous lesions, with > 90% efficacy against anogenital warts and clinical endpoints in most studies. For males, the protection offered by the five additional oncogenic strains has been tested by immunogenicity and the antibody responses are similar to those against the four original strains in the vaccine. Duration of protection following three doses has been demonstrated out to 10 years, and because the antibody kinetics following a two-dose schedule are similar, it is expected that a two-dose series will also provide long-lasting protection.

Estimates of the attributable fraction of HPV strains causing anal cancers in North American males are about 89% for HPV 16 and 18, and an additional 9% for the other five strains (types 31, 33, 45, 52, 58). HPV is also responsible for about 50% of penile, 35% of oropharyngeal (largely HPV type 16), and 25% of oral cavity cancers, with alcohol or tobacco responsible for the larger portion of oropharyngeal and oral cavity cancers. While the vaccine has not yet been demonstrated to provide protection against infections and cancers at these other sites, there is expectation that future studies will demonstrate this.

The HPV vaccines have a well-established record of safety, and while the majority of studies have been focused on safety in females, the safety profile is similar in males. The vaccine is associated with a higher rate of injection-site reactions than the 4-valent vaccine, attributable to a higher antigen content for each of the four original virus strains, addition of five strains, and higher concentration of the aluminum adjuvant. Autoimmune disorders have been a focus of several safety studies using administrative databases for large populations, and no associations have been found.

As for all immunization programs, the key success factor is uptake. The advice and support of BC physicians is key to that success.
—Monika Naus, MD, FRCP
Medical Director, Immunization Programs and Vaccine Preventable Diseases Service
BC Centre for Disease Control

This article is the opinion of the BC Centre for Disease Control and has not been peer reviewed by the BCMJ Editorial Board.