Immunogenicity of quadrivalence recombinant human papillomavirus vaccine (6, 11, 16 and 18 types) (Hansenulapolymorpha): results from phaseI clinical trial
Objective 
To make a preliminary assessment on the immunogenicity of a quadrivalence recombinant human papillomavirus (HPV) vaccine (6, 11, 16 and 18 types) (Hansenulapolymorpha) in healthy women aged 18-45 years in phaseⅠclinical study. 
 
 
Methods 
It was a single-center, double-blind, randomized, placebo-controlled phaseⅠ clinical study. Women aged 18-45 years were randomized (2∶1) to receive HPV vaccine (n=60) or placebo control (n=30) at months 0, 2 and 6. Antibodies against HPV6/11/16/18 were detected by pseudovirus-based neutralisation assay in serum samples collected at 0 d, 180 d and 210 d. Seroconversion rates and geometric mean titres (GMT) of antibodies against the four types of antigens were calculated. 
 
 
Results 
Seroconversion rates of the vaccination group at 180 d (before the third dose) and 210 d (one month after the third dose) were generally similar and between 85%-100% for all types of antibodies. The GMT of antibodies at one month after the last dose improved significantly compared with those before immunization. 
 
 
Conclusions 
These results showed that the HPV vaccine had good immunogenicity in the population of healthy women aged 18-45 years. Higher antibody titers were elicited by the vaccine compare with the tites before the first dose and in the placebo control group. 
 
 
Key words: 
Quadrivalence recombinant human papillomavirus vaccine (6, 11, 16 and 18 types) (Hansenulapolymorpha); Immunogenicity; Seroconversion rate; Geometric mean titer