P-2. Public Health and Economic Impact of Implementing Gender-Neutral Vaccination with the 4-Valent Human Papillomavirus Vaccine in Costa Rica
Authors: Carlos Orengo Juan , Marisol Rendon Ana , Cristina Lima Bruna , Pavelyev Andrew , Daniels Vincent , Saxena Kunal , Herrera-Solano Wilberth , Parellada Cintia I 
Published: January 2025

Abstract

Background
In 2019, the quadrivalent human papillomavirus female only-vaccination (4vHPV-FOV) was introduced for 10-year-old girls in the Costa Rican National Immunization Program. This analysis aims to estimate the public health impact and the incremental cost-effectiveness of switching from a 4vHPV-FOV to a 4vHPV-GNV in Costa Rica.Table 1.Main parameters used in the model

Methods
A validated dynamic model of HPV disease transmission was calibrated to simulate the natural history of HPV infection and attributable disease burden in Costa Rica. The model assumed a two-dose schedule over a 100-year time horizon, lifetime immunity after vaccination, continuous cytology screening, and herd immunity. The outcomes measured were incremental averted cases and deaths of cervical, vaginal, vulvar, anal, penile, head & neck HPV-attributable cancers; recurrent respiratory papillomatosis, genital warts, and cervical intraepithelial neoplasia (CIN); and incremental cost-effectiveness ratio (ICER) expressed in quality-adjusted life years. Outcomes and costs were discounted at 3% annually rate. Costa Rica specific data were used for calibration (Table 1). The WHO definition of cost-effectiveness was used to define the threshold of highly cost-effective (ICER &lt; 1 GDP/per capita or US$13,365.4 for Costa Rica).Table 2.Additional avoided cases/cumulative percent reduction and deaths/mortality percent reduction of HPV-attributable diseases and cancers with 4vHPV-GNV strategy relative to 4-HPV-FOV over 100 years in Costa Rica.

Results
After 100 years, the 4vHPV-GNV strategy was projected to avert an additional 206,211 cases and 481 deaths compared to 4vHPV-FOV. The greatest reductions in burden and costs were due to HPV-6/11-attributable diseases (Table 2 and Fig. 1). For HPV 16 and 18-attributable cancers, the greatest reductions in burden were observed in cervical cancer, CIN 1 and 2/3 for females, and head & neck and penile cancers for males (Fig 1 and 2). 4vHPV-GNV was highly cost-effective with an ICER of US$ 2,166.Figure 1.Estimated healthcare costs avoided over 100 years by HPV genotype in Costa Rica

Conclusion
In Costa Rica, switching from a 4vHPV-FOV to a 4vHPV-GNV strategy is projected to be a cost-effective intervention, providing a substantial public health impact in both genders. The 4vHPV-GNV scenario would result in faster and greater reductions in the incidence of HPV 6/11/16/18-attributable diseases and cancers compared to the 4vHPV-FOV.Figure 2.Estimated HPV 6/11/16/18-attributable disease and cancer incidence over 100 years in Costa RicaA.Genital warts among females, B. Genital warts among males, C. Anal cancer among males, D. Head & Neck cancers among males

Disclosures
Juan Carlos Orengo, MD, MPH, PhD, Merck & Co., Inc: Employee|Merck & Co., Inc: Stocks/Bonds (Private Company) Ana Marisol Rendon, MD, MS, Merck & Co., Inc: Employee|Merck & Co., Inc: Stocks/Bonds (Private Company) Bruna Cristina Lima, n/a, Merck & Co., Inc: Employee Andrew Pavelyev, n/a, HCL America, Inc.: emplo Vincent Daniels, PhD, Merck & Co., Inc: Employee|Merck & Co., Inc: Stocks/Bonds (Private Company) Kunal Saxena, PhD, Merck & Co., Inc: Stocks/Bonds (Private Company) Wilberth Herrera-Solano, MD, Consultant: Consultant Cintia I. Parellada, MD, PhD, Merck & Co., Inc: Employee|Merck & Co., Inc: Stocks/Bonds (Private Company)