Human papillomavirus infection is the known cause of more than 5% of all malignant diseases associated with infections and includes cervical, vaginal, vulvar, anal, and oropharyngeal cancer, as well as one of the major causes of cervical cancer, which remains one of the top chronic diseases globally for women's health. It's also the most common viral sexually transmitted infection worldwide (1, 2). Cervical cancer ranks as the fourth most common malignancy in women and is among the leading causes of cancer-related deaths worldwide, particularly in low- and middle-income countries (3). However, screening for cervical cancer can identify precancerous changes (cervical dysplasia) and early-stage cervical cancers. Persistent infection with high-risk human papillomavirus (HR-HPV) genotypes is recognized as the necessary etiological factor for cervical carcinogenesis, with HPV-16 and HPV-18 responsible for approximately 70% of cases worldwide (4). HPV prevalence varies from country to country based on the rates of vaccination and screening. However, geographic heterogeneity of genotype distribution is remarkable, and knowledge of these variations is indispensable to tailor screening and prevention programs. These results suggest that local and global genotype landscapes often diverge from each other, which raises the issue of region-specific vaccination strategies. In addition, modeling estimates that increasing vaccine coverage, particularly in areas with low access, could avert hundreds of thousands of additional cases of cervical cancer each year (5).

In Türkiye, HPV prevalence exhibits substantial variability across centers, with reported rates ranging from about 10% to 40% (6, 7). Because the HPV vaccine has not yet been included in the national immunization program, vaccination uptake remains very low, with published rates ranging from 1.4% to 3.6% (8, 9). High-risk HPV prevalence may reach 18%–24% in some cohorts, and HPV-16 consistently remains the predominant genotype nationwide (7, 10). In addition to cervical cancer, HPV is associated with a range of cancers that affect both men and women, such as anal, vulvar, vaginal, penile, and oropharyngeal. Its role is different among anatomical sites, though. For example, an analysis of studies on oral cavity squamous cell carcinoma (primary site, oral cavity and oropharynx) found that HPV was present in just 6% of tumors, indicating a substantially less strong etiologic relationship than for oropharyngeal cancer (11). These subtleties reinforce the need to interpret genotype prevalence and oncogenic potential in an anatomic and epidemiologic perspective. The landscape of prevention has been dramatically altered with the introduction of HPV vaccination. Results of both clinical and population-based trials support strong declines in the prevalence of HPV-16 and HPV-18 after vaccine introduction.

Nonetheless, the threat of genotype replacement or persistence by non-vaccine types such as HPV-52, HPV-58, and HPV-31, which continue to cause high-grade lesions in vaccinated populations, exists (12, 13). Worldwide investigations demonstrated that currently available vaccines include most, but not all, of the genotypes responsible for cancer development, and highlight the significance of continued monitoring as well as improving vaccine versions (14). Screening is just as important in the age of a vaccine. Conventional Pap cytology, although very effective, is less sensitive than HPV testing. Co-testing and primary HPV testing have become more popular, reported to increase the detection rate of high-grade intraepithelial lesions (15, 16). Moreover, population-based programs in Europe and Asia have shown that adding HPV testing to national screening strategies leads to earlier detection and a lower incidence of invasive cancers (16). Therefore, the description of the distribution of HPV genotypes has become even more vital for further knowledge on the epidemiology and aetiological aspects of the disease for health preventive strategies.

A total of 4,648 women were included in the study. Of these, 82.3% (n = 3,823) were HPV negative and 17.7% (n = 825) were HPV positive. Logistic regression analysis was conducted to examine how HPV positivity varied across age groups. Using women aged 50–65 years as the reference category, the model showed that age was an important predictor of HPV positivity (p < 0.01). Women younger than 30 years had significantly higher odds of being HPV positive compared with the reference group (OR: 2.55; p < 0.01). A similar pattern was observed in the 40–49 year age group, which also demonstrated an increased risk (OR: 1.77; p < 0.01). In contrast, women aged 30–39 years had only a slight, non-significant rise in HPV positivity (OR: 1.32; p = 0.08). Overall, the findings indicate a clear bimodal distribution, with HPV positivity peaking in women under 30 years of age and again in those aged 40–49 years. This regression pattern confirms that these two age groups carry considerably higher risk of HPV infection compared with women aged 50–65 years (Table 1).

When the relationship between age groups and infection type (single vs. multiple) was examined, the distribution of infection types was found to be unequal. The proportion of multiple infections was higher than expected in the <30 year group. Multiple infections were particularly more common in the younger age group (<30 years), which was statistically significant (OR: 1.46; p = 0.01). In contrast, the 40–49 year group showed a lower-than-expected proportion of multiple infections (p < 0.001) (Table 2).

No significant differences were observed in the cytology distribution between single and multiple HPV infections (p = 0.41). However, the cytology distribution of HPV-16 positive cases differed significantly compared with other HPV types (p < 0.001). HPV-16 was more frequently detected in high-grade lesions (HSIL, ICC). The most frequently identified genotype was HPV-16 (23%), followed by HPV-6 (13.3%), HPV-51 (6.6%), and HPV-59 (6.2%). Logistic regression analysis revealed that HPV-16 was the only genotype significantly associated with an increased risk of HSIL/ICC (OR: 6.40; p < 0.001). None of the other genotypes—including HPV-18, HPV-31, HPV-33, HPV-52, and HPV-66—showed a meaningful association with high-grade lesions. Similarly, multiple infections did not confer additional risk compared with single infections (Table 3).

When cytology results were evaluated, HPV positivity was below 10% in the normal cytology group, whereas it was significantly higher in ASCUS and LSIL cases (p < 0.001). In particular, HPV positivity exceeded 70% in HSIL cases, with HPV-16 being the predominant type. Overall, while the majority of women with normal cytology were HPV negative, the presence of cytological abnormalities was, as expected, associated with a marked increase in HPV positivity.

In this study, we evaluated HPV prevalence, genotype distribution, and their relationship with cytological outcomes in a large cohort of 4,648 women from western Türkiye. HPV positivity was 17.7%, which is slightly lower than the prevalence reported in some regional Turkish studies, where positivity ranged between 20–25% (18). This difference may be attributed to population characteristics, screening practices, and methodological variations. Our findings showed that HPV positivity was not evenly distributed across age groups, with peaks in women younger than 30 years and in the 40–49 age group. This bimodal pattern is consistent with international observations, where an early peak corresponds to the onset of sexual activity and a later peak is thought to be related to immune senescence and viral reactivation (19, 20). Another important finding of our study was the higher frequency of multiple infections among younger women (<30 years). Although multiple infections are generally considered common in sexually active women, their clinical significance remains debated. Some studies reported no significant association between multiple infections and cytological abnormalities (21), whereas others suggested that coinfection may contribute to persistent high-risk HPV infections (20, 22). In our analysis, multiple infections were significantly more common in the younger age group, suggesting that host and behavioral factors may influence viral co-infections. Importantly, HPV-16 emerged as the dominant driver of high-grade lesions in our cohort. These results underscore the predominant influence of HPV-16 in the development of high-grade cervical lesions, aligning closely with global evidence. The lack of significant risk associated with other genotypes suggests that their oncogenic potential is comparatively limited in this population. Moreover, the finding that multiple infections do not increase HSIL risk further highlights the central role of HPV-16 rather than the overall burden of coinfection. Taken together, these findings emphasize the importance of genotype-specific surveillance and reinforce prevention strategies that particularly target HPV-16.

Genotype distribution in our cohort was dominated by HPV-16 (23%), followed by HPV-6, HPV-51, and HPV-59. This pattern is consistent with both national and international reports, which consistently show HPV-16 as the leading genotype associated with cervical cancer precursors (23, 24). The strong association between HPV-16 and high-grade lesions (HSIL, ICC) observed in this study further supports its well-established carcinogenic potential. Cytological analysis revealed that HPV positivity was below 10% in women with normal smears but exceeded 70% in those with HSIL, highlighting the strong causal relationship between persistent high-risk HPV infection and cervical carcinogenesis. Similar to our results, studies from Türkiye and Spain reported that HPV-16 was disproportionately represented in women with high-grade cytological abnormalities.

The impact of HPV vaccination on genotype distribution has been clearly demonstrated in countries with well-established immunization programs. Recent epidemiological evidence indicates that the prevalence of high-risk genotypes—particularly HPV-16 and HPV-18—declines substantially within a relatively short period following the implementation of widespread vaccination (12). This underscores the potential long-term benefits of strengthening national vaccination programs in Türkiye. The age-related bimodal distribution observed in our population is of particular clinical interest. The first peak, occurring in women younger than 25 years, aligns with findings from global meta-analyses that attribute this rise to the onset of sexual activity and increased exposure to HPV (23). The second peak in the 55–64 age group may be explained by immunosenescence, reactivation of latent infections, and hormonal changes in the peri- and postmenopausal period (19). These findings highlight the continuing need for screening not only in young women but also in older age groups who may otherwise be overlooked.

The role of multiple infections in cervical carcinogenesis remains controversial, but several recent studies suggest that coinfections may enhance viral persistence and disease progression. Luo et al. demonstrated that women with multiple infections had a significantly higher risk of persistent high-risk HPV positivity (25). Similarly, Chaturvedi et al. reported that the presence of multiple genotypes could increase the likelihood of developing cervical neoplasia. Although our data did not show increased HSIL risk in women with multiple infections, the higher rate of coinfection among younger women suggests that these infections may act as potential cofactors in a subset of individuals (26). Finally, the public health implications of our study are significant. While HPV-16 continues to be the predominant genotype associated with high-grade lesions, the detection of other high-risk types such as HPV-51 and HPV-59 at relatively higher rates underscores the potential benefits of nonavalent vaccines, which provide broader coverage. Incorporating such vaccines into the national immunization program could further reduce the burden of cervical cancer in Türkiye. Enhancing awareness campaigns and improving access to vaccination and regular screening remain essential components of effective cervical cancer prevention strategies.

In this large cohort of women from western Türkiye, HPV prevalence was 17.7%, with HPV-16 emerging as the predominant genotype and showing a strong association with high-grade cervical lesions. HPV positivity demonstrated a bimodal age distribution, and multiple infections were more common in younger women, highlighting the influence of both age and infection patterns on disease dynamics. These findings emphasize the need for continued surveillance of genotype distribution, sustained cervical cancer screening across all age groups, and the implementation of effective vaccination programs tailored to regional epidemiology. Despite being largely preventable, cervical cancer remains a non-eradicated malignancy due to insufficient implementation of HPV vaccination programs worldwide.