Methods: The LTFU program currently includes: 1) approximately 3,000 Nordic young women aged 16 to 26 years enrolled into the original protocol 015 efficacy study (FUTURE II; 2002-2003) who were subsequently followed through national registries; 2) 1,610 Colombian women aged 24 to 45 who originally enrolled into Protocol 019 efficacy study (FUTURE III; 2004-2005) and 3) 1, 781 sexually naïve U.S. boys and girls, aged 9 to 15 who originally enrolled into an immunogenicity study (Protocol 018; 2003-2004). For 019 women, examinations with cytology were performed at 12-month intervals and for 018, examinations with genital and vaginal swabs for HPV DNA in sexually active boys and girls were performed every 6 mos. Sera for immunogenicity was also collected at specified visits.
Results: Mean number of years for follow-up for P015, P019 and P018 subjects was 9, 8 and 6, respectively. No breakthrough cases of HPV 6/11/16/18-related genital warts or cervical intraepithelial neoplasia (CIN) I-3 were observed for any of the groups. In P018, there were 2 episodes of 6-month persistent infection in girls and 2 in boys. No lesions were observed. P015 year 9 seropositivity for HPV 6, 11, 16 and 18 was 98%, 96%, 100% and 91%, respectively in the total IgG assay. P019 year 6 total IgG seropositivity for HPV 6, 11, 16 and 18 was 88%, 84%, 100% and 82%, respectively. Year 8 seropositivity against HPV 6/11/16/18 in the extension of P018 based only on the cLIA (IgG data not yet available) was 88%, 89%, 97% and 64%, respectively. The rate of acquisition of new sexual partners among males (120.0/100 PY) in P018 tended to be higher compared to females (69.2/100 PY). No new vaccine-related safety concerns emerged in any population.
Conclusion: The qHPV vaccine continues to demonstrate effectiveness through 6 to 8 years following vaccination in boys, girls, young and adult women. The rate of persistent infection observed is similar to the rate seen in vaccinated populations and may represent deposition from an infected partner. No HPV type 18-associated breakthrough disease was observed.
A. B. Moscicki,