Author(s): Insinga RP, Perez G, Wheeler CM, Koutsky LA, Garland SM
We describe the incidence and duration of cervical human papillomavirus (HPV) infection episodes along with the risk of infection reappearance following a period of nondetection.
Women (1,788) ages 16 to 23 years underwent cytologic testing and PCR-based testing of cervical swab samples for HPV DNA (HPV-16/18/31/33/35/45/52/58/59) at approximately 6-month intervals for up to 4 years in the context of a phase 3 clinical trial (placebo arm). HPV type-specific incidence rates were estimated per 100 person-years. Duration of type-specific cervical infection episodes and risk of reappearance following a period of nondetection were estimated using Kaplan-Meier methods.
HPV-16 exhibited the highest (5.9), and HPV-35 and HPV-33 exhibited the lowest (1.0) incidence rates per 100 person-years. Mean cervical infection durations ranged from 13 months for HPV-59 to 20 months for HPV-16 and 58 (with ongoing infections censored at the time of treatment, if done). The risk of cervical infection reappearance within approximately 3 years following a period of nondetection ranged from 0% to 16% across HPV types, with a mean of 8%. Limited evidence was found for a role of false-positive HPV tests, missed infections that were above the threshold for detection, or new acquisition of infection in accounting for patterns of infection reappearance.
Incidence of high-risk cervical infection was observed to vary considerably more across HPV types than infection duration. A nontrivial proportion of women exhibited infection reappearance following a period of nondetection, with a potential explanation for many such events observed within this analysis being a return to detectable levels of a previously acquired infection.
The risk of HPV infection reappearance following a period of nondetection has not been previously reported for individual HPV types, and this study finds that a nontrivial proportion of infected women exhibit reappearances. Future studies could ascertain subject-level factors that potentially modify the risk of infection reappearance.Journal of Vaccines & Vaccination