HPV and Common STIs Overlap in Women: Large Shaanxi Study Maps Infection Patterns

A large cross-sectional study from Shaanxi Province, China, has mapped the prevalence of human papillomavirus (HPV) and five common sexually transmitted pathogens among nearly 32,000 women attending a gynecology outpatient department, offering one of the most detailed regional snapshots of how these infections overlap. The research, published in BMC Infectious Diseases by a team from The First Affiliated Hospital of Air Force Medical University and Xi’an Jiaotong University, analyzed 31,975 cervical exfoliated cell samples collected between January 2022 and November 2025. The findings underscore a central question in cervical cancer prevention: HPV infection alone is often insufficient to drive carcinogenesis, and co-existing sexually transmitted infections may act as cofactors that tip infected cells toward malignant transformation.

Cervical cancer remains a leading gynecological malignancy worldwide, and persistent infection with high-risk HPV is its principal cause. Yet the progression from HPV infection to cancer is not a simple one-way street. Chronic inflammation, disruption of the cervical epithelial barrier, and immune modulation caused by other genital pathogens are thought to facilitate the persistence of high-risk HPV and the development of lesions. The Shaanxi study set out to quantify how frequently HPV co-occurs with Chlamydia trachomatis (CT), Ureaplasma urealyticum (UU), Neisseria gonorrhoeae (NG), Mycoplasma hominis (MH), and Mycoplasma genitalium (MG), and to describe how these patterns vary across age groups.

The methodology was straightforward but large in scale. Vaginal swabs were obtained for nucleic acid testing of CT, UU, NG, MH, and MG DNA, while cervical exfoliated cells were subjected to HPV genotyping. Because the analysis was retrospective and descriptive, using anonymized clinical data, the ethics committee waived the requirement for individual informed consent. Detection rates were then calculated for each pathogen, for mixed infections, and for the co-occurrence of HPV genotypes with bacterial and mycoplasmal pathogens across different age strata.

The headline number is striking: the overall HPV infection rate in this population was 21.46 percent, meaning 6,862 of the 31,975 women tested positive for at least one HPV genotype. Genotype distribution followed a pattern that has important implications for vaccine strategy. HPV16 was the most prevalent genotype, followed by HPV58, HPV53, HPV52, and HPV61. This ranking is notable because HPV58 and HPV52, which are covered by the nonavalent vaccine, appear prominently in this Chinese cohort, while HPV53, a partially covered type, also ranks high. Regional differences in genotype prevalence are a key argument for tailoring vaccination and screening programs to local epidemiology rather than relying solely on data from other populations.

The bacterial and mycoplasmal pathogens showed distinctly different age profiles. Infection rates of Neisseria gonorrhoeae and Chlamydia trachomatis were highest in women aged 20 years or younger and declined steadily with age, a pattern consistent with the epidemiology of these classic sexually transmitted bacteria in younger, sexually active populations. Ureaplasma urealyticum infection peaked in the 21 to 30-year age group, the demographic window that typically encompasses peak sexual activity and childbearing. In contrast, Mycoplasma hominis prevalence increased with age and was highest in women over 50, suggesting that MH may behave less like a classic sexually acquired infection and more like an opportunistic colonizer whose detection rises as the vaginal microbiome and hormonal milieu change with age.

Mixed infections accounted for a minority of STI-positive cases, but their composition was informative. The combination of Ureaplasma urealyticum and Mycoplasma hominis was the most common mixed infection, with a detection rate of 2.24 percent, reflecting the high individual prevalence of these genital mycoplasmas. At the other extreme, triple infection with Chlamydia trachomatis, Ureaplasma urealyticum, and Mycoplasma hominis was rare, occurring at a rate of just 0.10 percent. The rarity of triple co-infection suggests that while dual colonization with mycoplasmas is common, the accumulation of multiple distinct pathogens in one patient is constrained, possibly by competitive interactions within the genital tract microbiome or by differences in transmission routes.

The association between HPV and the other pathogens emerged clearly in the genotype-level analysis. The authors report that in Shaanxi Province, women with positive samples for genital tract pathogens CT, UU, MH, MG, or NG had a higher likelihood of carrying HPV16, HPV52, HPV58, or HPV53. This co-occurrence pattern aligns with the cofactor hypothesis: bacterial and mycoplasmal infections may damage the cervical epithelium, provoke inflammatory responses, or alter local immunity in ways that favor the acquisition, persistence, or reactivation of high-risk HPV. Chlamydia trachomatis in particular has been repeatedly implicated in cervical cancer risk in prior literature because it can establish intracellular infections that trigger chronic inflammation without provoking strong protective immunity.

The technical basis of the study deserves attention because it illustrates how modern molecular diagnostics enable this kind of population-level mapping. HPV genotyping from cervical exfoliated cells identifies not just the presence of the virus but its specific genotype, allowing researchers to distinguish between the roughly dozen high-risk types and the many low-risk types that circulate in the population. Nucleic acid amplification testing of vaginal swabs for CT, NG, UU, MH, and MG DNA provides sensitive detection of organisms that are difficult or impossible to culture, particularly Mycoplasma genitalium, which has emerged in recent years as an important cause of pelvic inflammatory disease and is increasingly recognized as a cofactor in HPV persistence. The combination of these two testing platforms on paired specimens from the same patients is what makes co-infection analysis possible at this scale.

The clinical implications of the findings are layered. For screening programs, the high overall HPV prevalence of 21.46 percent in gynecologic outpatients reinforces the value of HPV-based cervical cancer screening, and the prominence of HPV16, 58, 53, and 52 in this population provides a benchmark for evaluating which genotyping panels and vaccines offer the best local coverage. For prevention, the association between bacterial STIs and high-risk HPV genotypes suggests that treating or preventing CT, NG, and genital mycoplasma infections could form part of a broader cervical cancer prevention strategy, not merely a strategy for controlling the STIs themselves. For clinicians, the age-specific patterns offer practical guidance: younger women warrant vigilance for gonorrhea and chlamydia, while older women may harbor Mycoplasma hominis more frequently than classic STI models would predict.

The study also has limitations inherent to its design. As a retrospective, single-center, descriptive analysis of gynecologic outpatients, it captures a clinical population rather than a random community sample, so the prevalence figures may not generalize to all women in Shaanxi or to asymptomatic populations. The cross-sectional nature means that temporal relationships cannot be established; the data show that HPV and other pathogens co-occur more often than expected, but they cannot demonstrate whether bacterial infections precede and promote HPV persistence, whether HPV infection increases susceptibility to bacterial pathogens, or whether both are driven by shared behavioral risk factors. Nevertheless, the sheer sample size of nearly 32,000 women, the systematic genotyping, and the multi-pathogen testing make this one of the most comprehensive regional datasets on HPV and STI co-infection in China, and the authors suggest that these findings can help in developing more effective intervention, prevention, and treatment strategies for sexually transmitted infections in the region.

Subject of Research: Prevalence of HPV and its co-occurrence with common sexually transmitted infections among women in Shaanxi, China

Article Title: Prevalence of HPV and its association with common sexually transmitted infections among women in Shaanxi, China: a cross-sectional study

Article References: Zheng, Y., Bai, J., Li, J., Liu, S., Chen, L., & Wang, G. (2026). Prevalence of HPV and its association with common sexually transmitted infections among women in Shaanxi, China: a cross-sectional study. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14362-8

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14362-8

Keywords: HPV, cervical cancer, sexually transmitted infections, Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, HPV16, genotype distribution, co-infection, Shaanxi China, cross-sectional study