Comparison of two recombinant hepatitis B vaccines and their interchangeability in Argentine infants

OBJECTIVE: To compare two pediatric recombinant hepatitis B vaccines-the Engerix-B reference vaccine and the Euvax-B vaccine-in terms of immunogenicity and reactogenicity, and also to investigate their interchangeability, that is, whether a three-dose hepatitis B vaccination schedule begun with a first dose of Engerix-B could be completed with two doses of Euvax-B. METHODS: This study was conducted in the city of Cordoba, Argentina, from March 1999 through February 2000. Three groups of Argentine newborns (100 per group) were vaccinated at 0, 1, and 6 months of age with hepatitis B vaccine: group A, three doses of Euvax-B; group B, three doses of Engerix-B; and group C, one dose of Engerix-B followed by two doses of Euvax-B. Reactogenicity was evaluated based on parental reporting of any solicited local or systemic event occurring during the 7-day period following vaccination. Whether Euvax-B and Engerix-B were clinically identical was assessed in terms of the seroprotection rates (antibodies to hepatitis B surface antigen (anti-HBsAg) >10 milli-international units per mL (mIU/mL) 2 months after the third vaccination). RESULTS: Reactogenicity was low in all three groups. Five months after the second dose (that is, immediately prior to the third vaccination), seroprotection rates were 95.9%, 94.7%, and 90.2% for groups A, B, and C, respectively. Two months after the third dose all subjects were seroprotected, with geometric mean concentrations of anti-HBsAg of 2 468.1, 1 714.8, and 2 075.3 mIU/mL for groups A, B, and C, respectively. CONCLUSIONS: Both of the recombinant hepatitis B vaccines that we studied were well tolerated and highly immunogenic. Euvax-B was clinically identical (not inferior) to the Engerix-B reference vaccine, and either vaccine could be used to achieve the World Health Organization goal of immunizing all infants against hepatitis B. Further, Euvax-B can be safely used in infants given an initial dose of either Euvax-B or Engerix-B.