Potential Impact of Catch-Up HPV Vaccination on HPV Prevalence and Cervical Cancer Incidence Among Women Living With HIV in South Africa: Results From Two Mathematical Models.

INTRODUCTION

Women living with HIV (WLHIV) face an increased risk of cervical cancer (CC). With inequitable human papillomavirus (HPV) vaccine access globally and a programmatic focus on girls-only school-based delivery, many WLHIV in high HIV prevalence countries remain vulnerable to HPV and CC. We assessed the incremental impact of adding catch-up vaccination for WLHIV in South Africa.

METHODS

We used two independently developed HPV/CC and HIV transmission models to predict the incremental impact of catch-up HPV vaccination for WLHIV compared to routine-only vaccination of girls aged 9-14 (90% cohort coverage) from 2020 onwards using a nonavalent vaccine (lifelong 100% protection). We assessed catch-up scenarios vaccinating WLHIV aged 15-24 or ≥15 (attaining 90% cohort coverage), maintaining baseline CC screening. We report the predicted median annual prevalence of vaccine-type high-risk HPV (VT HR-HPV), CC incidence and cumulative fraction of CC cases averted compared to routine-only vaccination among WLHIV overall (age-standardized) and by age.

RESULTS

With routine-only vaccination, overall coverage among all WLHIV remained substantially (>50%) lower than in all women for 35-40 years, with gaps persisting even after 80 years. Adding catch-up vaccination for WLHIV aged 15-24 increased coverage and benefits mainly among young WLHIV, with the largest annual reductions (relative to routine-only vaccination) in VT HR-HPV prevalence and CC incidence for WLHIV <30 years, reaching up to 36%-52% across models within 15 years and 38%-100% after 15-25 years, respectively. If catch-up included WLHIV aged ≥15, overall vaccination coverage among WLHIV would immediately increase to 90%, extending benefits to older WLHIV-reducing peak annual relative reductions in CC incidence among WLHIV ≥50 by an extra 19% points compared to catch-up vaccination of WLHIV aged 15-24, and shifting the peak 25 years earlier. Over 55-60 years, catch-up vaccination of WLHIV aged 15-24 and ≥15 could avert up to 3%-8% and 14% of CC cases among WLHIV, respectively.

CONCLUSIONS

Catch-up vaccination of WLHIV can reduce their CC burden in the short to medium term, even in the presence of girls-only routine vaccination programmes with high cohort coverage. To maximize impact, vaccines should be offered to WLHIV of all ages, not only younger women.