Background & Objective: HPV is a well-established risk factor for cervical cancer.
Vaccination against HPV, particularly targeting high-risk viral strains, significantly reduce the incidence of cervical cancer. This study was conducted with aim to investigate the histopathological spectrum of Cervical Intraepithelial Neoplasia (CIN) in HPV-vaccinated versus unvaccinated women in southwest of Iran.Materials & Methods: This descriptive-analytical, cross-sectional study was conducted at Imam Khomeini Hospital in Ahvaz, Iran, between ۲۰۲۰ and ۲۰۲۳. The study population consisted of women diagnosed with CIN based on cytology and confirmed by colposcopy and biopsy. Data collected included demographic characteristics, sexual history, contraceptive methods, menstrual status, smoking habits, history of genital warts, presence of immunodeficiency, cervical cytology results, histopathological findings, and HPV vaccination status. Statistical analysis of data was performed using Chi-square test for categorical variables and independent samples t-test for quantitative variables. P<۰.۰۵ was considered statistically significant.Results: The mean age of patients was ۳۸.۷۹±۸.۰۸ years. Of the ۳۸۴ patients, ۷.۸۱% had received the HPV vaccine. A statistically significant association was observed between HPV vaccination and genital wart type, with unvaccinated women showing a higher prevalence of malignant genital warts compared to vaccinated women (P=۰.۰۴). A significant association was also found between vaccination status and colposcopy results (P=۰.۰۴۹). The distribution of histopathological diagnoses showed no significant difference between the two groups (P=۰.۲۸), despite that a higher proportion of vaccinated women presented with normal histopathology.Conclusion: HPV vaccination was associated with a reduction in malignant cases and shifts in clinical outcomes. While this study didn’t show significant differences in certain histopathological outcomes, the overall reduction in HPV-related conditions among vaccinated individuals reinforces the critical role of HPV vaccination in disease prevention.