Laake I, Feiring B, Jonassen CM, et al. - In the present study, the researchers sought to examine concurrent human papillomavirus (HPV) infections in 17-year-old girls from two birth cohorts; the first vaccine-eligible cohort in Norway and a pre-vaccination cohort. This research was confined to unvaccinated girls from the pre-vaccination cohort (n = 5,245) and vaccinated girls from the vaccine-eligible cohort (n = 4,904). According to findings, unvaccinated girls were more often infected with multiple HPV types than vaccinated girls. In both unvaccinated and vaccinated girls, HPV33 and HPV51 appeared to be involved in co-infection. It does not appear that the implementation of HPV vaccination has had an effect on the tendency of specific types of HPV to cluster together.