Risk of newly detected infections and cervical abnormalities in adult women seropositive or seronegative for naturally acquired HPV-16/18 antibodies

BACKGROUND: Infections with human papillomavirus (HPV) types 16 and 18 account for ~70% of invasive cervical cancers but the degree of protection from naturally acquired anti-HPV antibodies is uncertain. We examined the risk of HPV infections as defined by HPV DNA detection and cervical abnormalities among women >25 years in the Human Papilloma VIrus Vaccine Immunogenicity ANd Efficacy trial's (VIVIANE, NCT00294047) control arm. METHODS: Serum anti-HPV-16/18 antibodies were determined at baseline and every 12 months in baseline DNA-negative women (N = 2687 for HPV-16 and 2705 for HPV-18) by enzyme-linked immunosorbent assay (ELISA) from blood samples. HPV infections were identified by polymerase chain reaction (PCR) every 6-months, and cervical abnormalities were confirmed by cytology every 12 months. Data were collected over a 7-year period. The association between the risk of type-specific infection and cervical abnormalities and serostatus was assessed using Cox proportional hazard models. RESULTS: Risk of newly detected HPV-16-associated 6-month persistent infections (PI) (hazard ratio [HR] = 0.56 [95%CI:0.32; 0.99]) and atypical squamous cells of undetermined significance (ASC-US+) (HR = 0.28 [0.12; 0.67]) were significantly lower in baseline seropositive vs baseline seronegative women. HPV-16-associated incident infections (HR = 0.81 [0.56; 1.16]) and 12-month PI (HR = 0.53 [0.24; 1.16]) showed the same trend. A similar trend of lower risk was observed in HPV-18-seropositive vs -seronegative women (HR = 0.95 [0.59; 1.51] for IIs, HR = 0.43 [0.16; 1.13] for 6-month PIs, HR = 0.31 [0.07; 1.36] for 12-month PIs, and HR = 0.61 [0.23; 1.61] for ASC-US+). CONCLUSIONS: Naturally acquired anti-HPV-16 antibodies were associated with a decreased risk of subsequent infection and cervical abnormalities in women >25 years. This possible protection was lower than that previously reported in 15- to 25-year-old women