Immunogenicity and safety of three consecutive lots of a new preservative-free inactivated hepatitis A vaccine (Healive®): A double-blind, randomized and controlled trial

SummaryImmunization is considered as the most effective way for the prophylaxis of hepatitis A virus (HAV) infection. This study aimed to evaluate the immunogenicity and safety of three consecutive lots of a new preservative-free inactivated hepatitis A vaccine (Healive®) in healthy children. A double-blind, randomized and controlled clinical trial was conducted in healthy volunteers aged from 1 to 8 years. Total 400 subjects were enrolled and assigned into four groups, receiving one of the three lots of Healive® or an established control vaccine. The vaccination was two-dose regimen with 6 months apart. Anti-HAV titers were determined at the 1st, 6th and 7th month. The results showed that Healive® was highly immunogenic in children with 100% seroconversion rate (SR) and 3237–3814 mIU/ml geometry mean titer (GMT) 1 month after the second dose. The immunogenicity of Healive® was statistically higher than that of the control vaccine with respect to GMT and SR (P = 0.037 to P < 0.001). Both Healive® and control vaccine were well tolerated with 1–5% incidence of overall adverse reactions (P > 0.298). Severe adverse reaction was not reported. Both SRs (1, 6 and 7 months) and GMTs (1 and 7 months) in subjects receiving one of the three consecutive lots of Healive® had not statistical difference (P = 0.114–0.710), suggesting that Healive® was well consistent. The immune responses in younger children (1–3 years) and older children (4–8 years) were similar to each other (P = 0.187–0.963). The present study indicated that Healive® was greatly consistent between production lots, well tolerated and highly immunogenic in children, which made the preservative-free inactivated hepatitis A vaccine well suitable for inclusion in the routine programme of children vaccination.