Prevaccination Study of Cervical Human Papillomavirus Types in Yangtze River Delta Area, China

Human papilloma virus (HPV) infection contributes as a main causative factor to the development of invasive cervical cancer (ICC) and its precursors (cervical intraepithelial neoplasia, CIN). Currently, two prophylactic vaccines are employed for the prevention of genital HPV infection. As the prophylactic efficacy is type-restricted, determining the type-specific HPV distribution and their associations with ICC and its precursors would provide essential information in assessment of HPV vaccination program impact. The baseline information is also important for monitoring possible changes in type-specific HPV distribution after vaccination has been introduced.

Prevalence of HPV infection varies considerably across the world, and data were limited from less-developed countries. Knowledge of the detail pattern of HPV type-specific distribution in each region will be essential for public health policy decisions. This will also form the basis for determining which types should be included in future generation HPV vaccines targeted to specific regions.

While most studies were focus on ICC and high-grade cervical lesions, the association between HPV types and the progression of CIN1 has rarely been studied. CIN1 is an insensitive histopathological sign of HPV infection, most of which will spontaneously regress to normal with host immune system. However, some genotypes have been described as being more persistent and associated with progression from low-grade lesions to high-grade lesions, even ICC. Geographical data on type-specific prevalence of HPV in CIN1 with appropriately designed prospective studies would be helpful in identifying types preferentially associated with progression to malignancy and accurately predicting the future impact of vaccination in specific regions.

Free vaccination supported by the government appears to be unlikely at present in China. Thus, individuals need to pay the cost of vaccines for themselves presently. Yangtze River Delta Area is the most economically developed regions in China, and people here may become the largest vaccinated population at their own expense in China. To the best of the investigators knowledge, no multi-center study on HPV type-specific distribution and their associations with ICC and its precursors is available in Yangtze River Delta Area, China, which highlights the need for timely study in this region before large scale vaccination programs are carried out.