Cellular immune responses 6 years following 1, 2, or 3 doses of quadrivalent HPV vaccine in Fijian girls and subsequent responses to a dose of bivalent HPV vaccine

Abstract

Background. This study examined the cellular immunity of 0, 1, 2, and 3 doses of Gardasil vaccine (4vHPV) in girls after 6 years and their responses to a subsequent dose of Cervarix vaccine (2vHPV). Methods. A subset of girls (n = 59) who previously received 0, 1, 2, or 3 doses of 4vHPV 6 years earlier were randomly selected from a cohort study of Fijian girls (age 15-19 years). Blood was collected before and 28 days after a dose of 2vHPV. The HPV16-and HPV18-specific cellular immune response was determined by IFNγ-ELISPOT and by measurement of cytokines in peripheral blood mononuclear cell supernatants. Results. Six years after 4vHPV vaccination, HPV18-specific responses were significantly lower in the 1-(1D) or 2-dose (2D) recipients compared with 3-dose recipients (2D: IFNγ-ELISPOT: P =.008; cytokines, IFNγ: P =.002; IL-2: P =.022; TNFα: P =.016; IL-10: P =.018; 1D: IL-2: P =.031; IL-10: P =.014). These differences were no longer significant post-2vHPV. No significant differences in HPV16 responses (except IL-2, P