Recent trends in type-specific HPV infection rates in the United States

This study examined recent trends in type-specific HPV infection rates in women referred for HPV typing as part of cervical cancer screening in the United States. HPV analyses were performed from March 2004 to March 2011. Women were aged 21-65 years at testing. The 18 most prevalent HPV types were analysed. Type-specific HPV infection rates were estimated in 3-month blocks. Lowess smoothing was used to examine time trends in infection rates for each HPV type, both combined, and separated by age group (younger women 21-30 years, older women 31-64 years). A total of 220914 women were included in the final analysis. The number of HPV tests performed on the younger age group increased, with the number of HPV infections and multiple type HPV infections decreasing. When separated by HPV type-specific analysis, the majority of HPV infection rates decreased; however, HPV types 61 and 83 increased. When analysing the older age group, there was a marked increase of the number of HPV tests. Overall, the rates of any HPV infection, as well as multiple type infections, were lower compared to the younger age group. The change in type-specific HPV rates in the older age group was minimal, with many rates remaining the same. In this population of women, overall rates of HPV infection decreased, while the number of HPV tests increased. Younger women had a more marked decrease in HPV infection rates, while for older women type-specific HPV infection rates appear consistent.