Changing to a single-dose HPV vaccine schedule: impact on vaccine uptake and inequities in Ireland

Cervical cancer disproportionately affects socioeconomically disadvantaged populations in Ireland. HPV vaccination is central to Ireland’s cervical cancer elimination strategy. In the 2022/2023 academic year, the school-based immunisation programme introduced a single-dose HPV schedule to simplify delivery and improve uptake. The impact of this change, particularly in disadvantaged schools where attendance rates are poorer, has not been examined. This was a retrospective register-based cohort study using national aggregate school-level data. Vaccine uptake among first-year secondary school students in Ireland was examined across four academic years, spanning the transition from a two-dose to a single-dose schedule. Delivering Equality of Opportunity in Schools (DEIS) status was used as a proxy for socioeconomic status. Median uptake percentages were compared using non-parametric tests. Associations between school characteristics and uptake were examined using multivariable linear regression, while logistic regression assessed factors linked to achieving the ≥90% uptake target. A total of 2,918 school records were analysed, with about one-third classified as DEIS. Median HPV uptake increased after the single-dose introduction (80.1%) compared to the previous year (73.6%) but declined to 76.4% by 2024/2025. Uptake was consistently lower in DEIS schools. Few schools achieved the ≥90% target (14.6% in 2022/2023), with DEIS schools significantly less likely to do so. DEIS status was independently associated with lower uptake, while fee-paying and all-girls schools showed higher uptake. Following the introduction of the single-dose HPV vaccine schedule, there was a short-term increase in uptake, but this was not sustained. DEIS schools consistently demonstrated 13–15% lower uptake. These findings suggest that while a single-dose schedule may reduce logistical barriers, other factors continue to influence HPV uptake.

Key messages

• Single-dose HPV vaccination led to a short-term rise in uptake, but gains were not sustained over time.

• Disadvantaged schools have consistently lower uptake and are less likely to reach the ≥90% target, highlighting persistent socioeconomic inequalities.