While much has been learned regarding the natural history of HPV, there is currently a growing focus on type-specific HPV associations rather than data grouped by broad categories (e.g., any oncogenic HPV type), which was common in the past. Randomized clinical trials, for example, are using the incident development of a persistent infection with a vaccine-related HPV type as an intermediate endpoint(5). Observational studies are also increasingly studying the natural history of HPV on a type-specific basis, whether to compare vaccinated versus unvaccinated women (in non-clinical trial settings), or to investigate other exposures while accounting for possible type-specific differences in effect estimates. The standard logistic regression and Cox model approaches commonly employed in HPV research up until now may not always be optimal for such analyses. More efficient statistical methods may need to be adopted.
