HPV vaccines are efficacious against HPV infections and associated lesions in women HPV-naïve at vaccination. However, VE against oncogenic, high-risk HPV types in women infected with any other HR-HPV type at first vaccination remains unclear.
This post-hoc analysis of phase II/III study evaluated AS04-adjuvanted HPV-16/18 VE against HR-HPV type infection in 871 Chinese women aged eighteen to twenty-five years over a 72-month follow-up period. In the total vaccinated cohort for efficacy, VE against 6-month and 12-month HPV-16/18 PIs in women DNA-negative to HPV-16/18 but DNA-positive to any other HR-HPV type at baseline was 100.0% and 100.0%, respectively. VE against HPV-16/18 incident infections in women DNA-positive to one vaccine type but DNA-negative to the other one at baseline was 66.8%. VE against HPV-31/33/45 incident infections, in women DNA-positive to HPV-16/18 and DNA-negative to the considered HPV type at baseline was 71.0%. No HPV-16/18 PIs were observed in vaccinated women with non-vaccine HPV A7/A9 species cervical infection at baseline.
The study concluded that women with existing HR-HPV disease at vaccination might still benefit from the AS04-HPV-16/18 vaccine. However, this potential benefit needs further demonstration in the future.