HPV Study in Suzhou’s Taihu Region Reveals Age-Linked Infection Patterns and Vaccine Insights

A large retrospective study of more than 23,000 women in the Taihu region of Suzhou, China, has mapped in fine detail how human papillomavirus circulates through the local population, which genotypes dominate, and how viral loads shift with age. The research, conducted by Jing Guo, Ruhong Yan, and Yijie Qu of the Department of Clinical Laboratory at the Affiliated Suzhou Hospital of Nanjing University Medical School, was published in Virology Journal and offers region-specific evidence that could sharpen cervical cancer prevention strategies in eastern China.

Human papillomavirus is the most common sexually transmitted infection worldwide and the necessary cause of nearly all cervical cancer cases. Yet the virus is far from uniform: its genotype distribution varies markedly between countries, regions, and even cities, and those differences matter enormously for vaccination policy. Prophylactic HPV vaccines target specific subsets of genotypes, so knowing which types actually prevail in a given population determines how much protection a vaccination program can realistically deliver. Because large-scale data on genotype prevalence and viral load characteristics in the Taihu region had been lacking, the research team set out to fill that gap with a three-year survey spanning January 2023 to December 2025.

The study design was straightforward but ambitious. The investigators analyzed cervical exfoliated cell samples collected from 23,196 women who underwent HPV testing at their institution during the study window. Each sample was screened for 21 HPV genotypes using real-time fluorescence quantitative polymerase chain reaction, a technique that both identifies the viral type present and quantifies how much viral DNA is in the specimen. This dual capability allowed the team to go beyond simple positivity rates and construct viral load profiles across age groups, a dimension that many prevalence surveys omit.

The headline finding was an overall HPV infection rate of 13.20 percent, with 3,061 of the 23,196 participants testing positive. Notably, this rate remained statistically stable across the three years of the study, suggesting an entrenched and steady level of viral circulation in the region rather than a rising or falling epidemic curve. That stability provides a useful baseline against which the future impact of vaccination and screening programs can be measured.

Perhaps the most striking pattern emerged when the researchers stratified infections by age. Rather than declining monotonically with age, as some classical models of HPV epidemiology predict, prevalence followed a bimodal distribution. The highest infection rate appeared in women aged 60 and older, while the lowest rate occurred among women aged 40 to 49. This shape echoes findings from other Chinese regions and reflects a complex interplay of factors: cohort effects in lifetime exposure, changes in immune competence with age, hormonal shifts after menopause, and possibly reduced participation in screening among older women, allowing persistent infections to accumulate undetected.

The genotype ranking carried direct implications for vaccine policy. Among high-risk types, HPV52 led with a prevalence of 2.70 percent, followed by HPV58 at 1.72 percent, HPV16 at 1.35 percent, HPV39 at 1.11 percent, and HPV56 at 0.96 percent. Among low-risk genotypes, HPV53 was the most common, detected at 1.78 percent. HPV16, the single most carcinogenic type globally, ranked only third locally, while HPV52 and HPV58, types that are notably overrepresented in Asian populations relative to Western ones, dominated. This regional signature matters because the bivalent and quadrivalent vaccines, which target HPV16 and HPV18 (with the quadrivalent also covering HPV6 and HPV11), would leave a substantial fraction of local infections uncovered. The nonavalent vaccine, which adds HPV31, HPV33, HPV45, HPV52, and HPV58 to the mix, aligns far better with the genotype spectrum observed in Taihu, and the authors concluded that their data show greater theoretical concordance with the nine-valent formulation.

Age also shaped the composition of infections in ways that compound the vulnerability of older women. Women aged 60 and above exhibited significantly higher proportions of high-risk mixed infections and multiple-genotype infections compared with all other age groups. Multiple infections, in which two or more HPV types coexist in the same cervical sample, are of particular clinical interest because co-infection can complicate risk stratification and may reflect broader exposure or diminished viral clearance. The elevated burden of mixed high-risk infections in older women underscores that HPV is not simply a concern of young adulthood and that screening programs must not neglect postmenopausal populations.

The viral load analysis added a further layer of nuance. Viral load, typically measured as the quantity of viral DNA per cellular sample, is thought to correlate with infection persistence and lesion risk, although its clinical interpretation remains debated. In this cohort, the distribution of viral loads varied systematically with age. High viral loads were most frequent among women under 30, accounting for 24.29 percent of infections in that group, whereas low viral loads predominated among women aged 60 and older, making up 46.82 percent of their infections. One plausible interpretation is that younger women carry more recently acquired, actively replicating infections that are often cleared by the immune system, while older women more frequently harbor long-standing, low-level persistent infections whose cumulative cellular damage may be clinically significant despite modest viral quantities.

Taken together, the results sketch a coherent picture of HPV epidemiology in the Taihu region: a stable overall prevalence near 13 percent, a genotype hierarchy led by HPV52, HPV58, and HPV16, a bimodal age distribution peaking in the oldest women, and an age-dependent viral load architecture. The authors argue that these findings argue for region-specific prevention and control strategies rather than one-size-fits-all policies. In practical terms, that means prioritizing vaccines whose genotype coverage matches local circulating types, sustaining and possibly extending cervical screening into older age brackets, and considering viral load and multiple-infection status when triaging positive results in clinical practice.

The study also demonstrates the value of quantitative PCR-based surveillance as a public health instrument. By combining genotyping with viral load quantification across a very large sample, the Taihu dataset offers a template for other regions in China and beyond that lack local HPV epidemiology. As vaccination programs scale up globally, longitudinal studies of this kind will be essential for tracking shifts in genotype prevalence, detecting vaccine-type declines, and identifying any replacement by non-vaccine types. For now, the message from Suzhou is clear: the local viral landscape favors the broadest available vaccine coverage, and older women deserve renewed attention in the campaign against cervical cancer.

Subject of Research: Epidemiology, genotype distribution, and viral load profiles of human papillomavirus infection among women in the Taihu region of Suzhou, China

Article Title: Epidemiological characteristics, genotype distribution, and viral load profiles of human papillomavirus infection among women in the Taihu region of Suzhou: a retrospective study

Article References: Epidemiological characteristics, genotype distribution, and viral load profiles of human papillomavirus infection among women in the Taihu region of Suzhou: a retrospective study. (n.d.). https://doi.org/10.1186/s12985-026-03301-3

Image Credits: AI Generated

DOI: 10.1186/s12985-026-03301-3

Keywords: human papillomavirus, HPV prevalence, HPV52, HPV58, HPV16, genotype distribution, viral load, cervical cancer, nonavalent vaccine, Suzhou, retrospective study, qPCR