Safety and immunogenicity of 23-valent pneumococcal polysaccharide vaccine (PPV23) in Chinese children, adults and elderly: a phase 4, randomized, double-blind, active-controlled clinical trial

ObjectivesA randomized, double-blind, active-controlled noninferiority phase 4 clinical trial was conducted to evaluate the immunogenicity and safety of a 23-valent pneumococcal polysaccharide vaccine (PPV23). MethodsPneumococcal vaccine-naive participants aged [≥]2 years were randomly assigned in a 2:1 ratio to receive a single dose of either the treatment vaccine (n=1199) or a comparator vaccine (n=600). We evaluated the immunogenicity before and 30 days post-vaccination, by measuring serum IgG serotype-specific pneumococcal antibodies to 23 serotypes contained in the vaccines via an enzyme-linked immunosorbent assay. The primary outcome was seroconversion (two-fold increase) of serum IgG serotype-specific antibodies at days 30 compared with baseline. ResultsOne month after the administration of PPV23, seroconversion rates for each of the 23 serotypes ranged from 59.22% to 95.67% in the treatment group, and in the control group from 59.66% to 94.07%. The lower bound of the 95% confidence interval (95%CI) of the rate differences for the 23 serotypes were all larger than -10%. Moreover, 12 serotypes (6B, 23F, 1, 2, 4, 8, 9N, 9V, 11A, 15B, 17F and 18C) had a lower bound of 95%CI for rate difference larger than 0. In total, 236 (19.68%) participants in the treatment group and 118 (19.67%) in the control group reported adverse reactions within 30 days poste-vaccination. No significant differences in incidence of adverse reactions were found between the two comparison groups. ConclusionsThe PPV23 vaccine administered among individual aged [≥]2 years was safe, well tolerated and immunogenic, eliciting immune response either comparable to or higher than control vaccine.