Abstract Background Cervical uterine cancer (CUCa) is the fourth most common female neoplasm globally. At least 99% of CUCa cases are caused by persistent infection of high-risk Human Papillomavirus (HR-HPV) types. In 2014, Chile began a mandatory immunization plan for 9-year-old girls with the GARDASIL™ vaccine, which confers immunity against types 16 and 18 that cause about 70% of CUCa. This work aims to estimate this vaccine's effectiveness in women after nine years of inoculation. Methods We evaluated the results for HPV detection from 21.676 women between 15 and 77 years old between 2019 and 2023 at Bupa Lab. HPV detection and genotyping was performed with the ROCHE Cobas® HPV Test. Effectiveness was measured as the ratio between the number of cases of HPV types 16+18 versus other HR-HPV. Results During the analyzed period, the number of tests performed increased significantly, and the positivity rate decreased from 44% in 2019 to 26,9% in 2023. Global positivity was 32% for some HR-HPV types, reaching a peak of 49,5% in the 20 to 24,9 years group. The average 16+18/other HR ratio was 0,39, which decreased significantly to 0,24 in the vaccinated group of women between 15 and 19,9 years, suggesting an effectiveness of 37,5% against HPV types 16 and 18 concerning the total HR types (Table 1). Conclusions In recent years, HPV detection has proven useful in preventive monitoring and early detection of CUCa. This increased awareness has triggered a significant rise in HPV testing and could be driving test positivity downwards. Although a more appropriate study design is required to estimate the actual effectiveness of the vaccine in Chile, our analyses showed a significant decrease in HPV types 16 and 18 in women after nine years of vaccination, which represents a crucial advance toward the eradication of CUCa.
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