In other words, one partner frequently came into the relationship with HPV and quickly transmitted it to the other. I was startled by the transmission frequency in these young adult females, who considered themselves in stable relationships. It suggests that acquisition is not just in early adolescence (although the risk of persistence is higher in that age group) and that catch-up immunization may be more important than some have thought. Perhaps these data won't convince all of your patients to get the HPV vaccine, but it may be helpful in some who are in their late teens or precollege age.