Subjects receiving HPV@ vaccine at month @ ( mean age @ years ) had a similar baseline rate of seropositivity to @ of the @ HPV types to those vaccinated at day @ ( mean age @ years ; @ % -LSB- @ of @ -RSB- vs @ % -LSB- @ of @ -RSB- ) ; however , @ of the @ subjects vaccinated at the later age were seropositive to @ vaccine types , indicating previous HPV exposure .