Safety and immunogenicity in 3-5 months-old infants after primary and boosting immunization with Hib PRP-TT conjugate vaccine / 中华微生物学和免疫学杂志

ABSTRACT

Objectives To evaluate the safety and immunogenicity of Haemophilus influenzae type b capsular-tetanus toxoid(Hib-TT) conjugate vaccine.Methods In an open-controlled,randomized trial,the eligible and consented infants of 3 to 5 months-old received 3 doses of Hib-TT or a licensed Hib-TT conjugate vaccine(Anerbao) as the control vaccine to evaluate safety; The serum anti-Hib PRP IgG antibody mean geometric concentration (GMC) in both groups after primary and boosting vaccination were measured by ELISA.Results No apparent difference in the frequency of total adverse reactions observed between two groups (study vaccine 23.85％ vs.comparator 31.40％) (x2=0.5,P＞0.05).The mild and severe fever reaction of both vaccines was 3.67％ and 4.48％ respectively,with no significant difference.The local reactions including erythema,swelling and induration reported was 1.22％ in study vaccine group.After 3 injections,the serum anti-Hib PRP IgG antibody GMC was 6.6686 μg/ml in study group and 7.5346 μg/ml in control group,with no significant difference in both of the antibody GMC (x2 =0.147,P=0.702).After one dose boosting injection,the serum antibody GMC in study group increased from 2.6396 μg/ml of preboosting to 6.2044 μg/ml of post-boosting.Conclusion The Hib-TT conjugate vaccine is proved to be safe in 3-5 months-old infants.The primary immune schedule for 3-5 months-old infants of 3 injections 1 month apart with the Hib-TT conjugate vaccine could induce IgG antibody response against Hib PRP with the GMC of long-term protection concentration in serum.A boosting dose after primary vaccination elicited obviously immunological memory.