Global burden of human papillomavirus and related diseases

The worldwide prevalence of infection with human papillomavirus (HPV) in women without cervical abnormalities is 11-12% with higher rates in sub-Saharan Africa (24%), Eastern Europe (21%) and Latin America (16%). The two most prevalent types are HPV16 (3.2%) and HPV18 (1.4%). Prevalence increases in women with cervical pathology in proportion to the severity of the lesion reaching around 90% in women with grade 3 cervical intraepithelial neoplasia and invasive cancer. HPV infection has been identified as a definite human carcinogen for six types of cancer: cervix, penis, vulva, vagina, anus and oropharynx (including the base of the tongue and tonsils). Estimates of the incidence of these cancers for 2008 due to HPV infection have been calculated globally. Of the estimated 12.7 million cancers occurring in 2008, 610,000 (Population Attributable Fraction [PAF]=4.8%) could be attributed to HPV infection. The PAF varies substantially by geographic region and level of development, increasing to 6.9% in less developed regions of the world, 14.2% in sub-Saharan Africa and 15.5% in India, compared with 2.1% in more developed regions, 1.6% in Northern America and 1.2% in Australia/New Zealand. Cervical cancer, for which the PAF is estimated to be 100%, accounted for 530,000 (86.9%) of the HPV attributable cases with the other five cancer types accounting for the residual 80,000 cancers. Cervical cancer is the third most common female malignancy and shows a strong association with level of development, rates being at least four-fold higher in countries defined within the low ranking of the Human Development Index (HDI) compared with those in the very high category. Similar disparities are evident for 5-year survival-less than 20% in low HDI countries and more than 65% in very high countries. There are five-fold or greater differences in incidence between world regions. In those countries for which reliable temporal data are available, incidence rates appear to be consistently declining by approximately 2% per annum. There is, however, a lack of information from low HDI countries where screening is less likely to have been successfully implemented. Estimates of the projected incidence of cervical cancer in 2030, based solely on demographic factors, indicate a 2% increase in the global burden of cervical cancer, i.e., in balance with the current rate of decline. Due to the relative small numbers involved, it is difficult to discern temporal trends for the other cancers associated with HPV infection. Genital warts represent a sexually transmitted benign condition caused by HPV infection, especially HPV6 and HPV11. Reliable surveillance figures are difficult to obtain but data from developed countries indicate an annual incidence of 0.1 to 0.2% with a peak occurring at teenage and young adult ages. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.