Infection with oncogenic human papillomavirus (HPV) remains a leading cause of cervical cancer and other HPV-related diseases. This situation persists despite the availability of effective prophylactic vaccines. While global vaccination programs have significantly reduced the incidence of HPV in adolescents and young adults, many women presenting with HPV infection or squamous intraepithelial lesions (SIL) were not covered by primary prevention. This review was performed with the aim of evaluating the impact of administering the 9-valent HPV vaccine in adult women who are HPV-positive or have histologically confirmed cervical precancerous lesions. Following the PRISMA 2020 guidelines, a search was performed in the MEDLINE, Scopus, and Cochrane Library databases. A total of 653 studies were retrieved, of which 7 studies, including 19,414 women, met the inclusion criteria. According to the literature, vaccination was linked to significant reductions in persistent HPV infection, progression of SIL, and recurrence…