From the Guidelines
The efficacy of the HPV vaccine is significantly higher after the second dose, with over 90% efficacy against targeted HPV types, compared to approximately 50-80% efficacy after the first dose alone. The HPV vaccine has been shown to provide primary protection against cancers related to HPV types 16 and 18, which are responsible for ∼70% of HPV-related cancers in the United States 1. The 9-valent HPV vaccine (9vHPV) includes coverage for the original 4 HPV types (6,11,16, and 18) in the quadrivalent vaccine and for the high-risk HPV types 31,33,45,52, and 58, which are responsible for an additional 14% of HPV-related cancers in women and 4% of HPV-related cancers in males in the United States 1.
The immune response with a 12-month interval between the 2 doses was more robust than that measured when the interval was only 6 months 1. Geometric mean antibody titers against all HPV types in the 9vHPV vaccine were higher in the 9- through 14-year-old age groups than in the 16- through 26-year-old women 1. For adolescents aged 9-14, a two-dose schedule (0,6-12 months) is now considered sufficient for full protection, while those 15 and older still require three doses (0,1-2,6 months) to achieve optimal immunity 1.
Key points to consider:
- The HPV vaccine provides significant protection against HPV-related diseases, including cervical cancer
- The second dose of the HPV vaccine acts as a booster, strengthening and prolonging the immune response initiated by the first dose
- Completing the recommended dosing schedule is crucial to maximize protection against HPV-related diseases
- The 9vHPV vaccine provides broader protection against HPV types compared to the quadrivalent vaccine
- Health care provider recommendation and physician attitude play a major role in the decision to vaccinate against HPV 1
From the Research
Efficacy Difference Between Dose 1 and Dose 2 of the HPV Vaccine
- The efficacy of the Human Papillomavirus (HPV) vaccine has been studied in various doses, including one-dose, two-dose, and three-dose schedules 2, 3, 4, 5, 6.
- Studies have shown that two doses of the HPV vaccine can provide comparable immunogenicity to three doses when administered to younger girls 2.
- A systematic review and meta-analysis found that a two-dose schedule for HPV vaccine provides satisfactory immunological outcomes in adolescent girls, with geometric mean concentrations (GMC) of antibodies against HPV16 and HPV18 being non-inferior or inconclusive compared to a three-dose schedule 6.
- Another study found that most studies evaluated impact of buffer periods (lag time) for case counting and different intervals between doses for two-dose vaccine recipients, and that significant effectiveness was found among 28/29 studies that evaluated three doses, 19/29 that evaluated two doses, and 18/30 that evaluated one dose 5.
- The World Health Organization (WHO) has recommended a 2-dose schedule for teens who begin the series before age 15, with doses spaced a minimum of 6 months apart 3, 4.
- Some jurisdictions with limited resources may consider initiating a one-dose vaccination with the possibility of giving the second dose later in life if judged necessary, to facilitate vaccination implementation and accelerate the impact on cervical cancer and other HPV-associated diseases 2.
Key Findings
- Two doses of the HPV vaccine can provide comparable immunogenicity to three doses in younger girls 2.
- A two-dose schedule provides satisfactory immunological outcomes in adolescent girls 6.
- Significant effectiveness was found among studies that evaluated one, two, and three doses of the HPV vaccine 5.
- The WHO recommends a 2-dose schedule for teens who begin the series before age 15 3, 4.