Estimating the prevalence of non-cervical human papillomavirus infection in mainland China (PROGRESS-Plus): protocol of a national cross-sectional study

Human papillomavirus (HPV) infection is the most common sexually transmissible infection worldwide. Although the prevalence of cervical HPV infection has been extensively reported in women worldwide, few epidemiological studies have examined the prevalence of non-cervical HPV infection among both women and men, especially in China.PROGRESS-Plus is a national, multisite, cross-sectional study that aims to estimate the prevalence of non-cervical HPV infection in women and men aged 18-60 years residing in mainland China. More specifically, PROGRESS-Plus will estimate the prevalence rate of HPV DNA in oral samples from both women and men, and that of anogenital samples from men. The secondary study objectives are to (1) report the aforementioned prevalence rates by HPV genotype, age and geographical region, (2) examine the concordance (ie, prevalence of the same HPV genotype) between the oral and anogenital samples among men, (3) explore risk factors associated with oral (in both women and men) and anogenital (in men only) HPV infection and (4) describe study participants' health-related quality of life, health behaviour, sexual behaviour and health status.The study protocol and all required documents have been submitted for review and approval to the Independent Ethics Committees of all the participating sites. All participants will provide their written informed consent on study entry, and all the recorded data will be treated as confidential.