Few data are available concerning the long term immunogenicity of the pediatric doses of hepatitis B vaccines given to preteenagers. The long term effect of the booster dose in teenagers is unknown. We evaluated the immunogenicity of 2 pediatric hepatitis vaccines after primary vaccination and after a booster dose.
A prospective 15-year follow-up study of the immunogenicity of 2 hepatitis B vaccines was initiated in 1995 in Quebec City, Canada. One year apart, 1129 children 8–10 years old received Engerix-B 10 μg (EB), and 1126 received Recombivax-HB 2.5 μg (RB) vaccine after a 0-, 1-, 6-month schedule. After 5 years, one-third of the 2 cohorts were randomly selected. A booster dose of EB 10 μg or RB 5 μg was administered according to the vaccine used in the primary immunization. Antibodies were measured before, 1 month after and 1 year after the booster injection.
Before the booster dose, anti-HB surface antibody (HBs) was detected in 94.7% of the EB subjects and in 95.2% of the RB subjects (P = 0.85). The geometric mean titer (GMT) was higher in the EB than in the RB group (252 mIU/mL versus 66 mIU/mL, P < 0.0001). One month after the booster, 99.7% of subjects in the EB group and 99.6% in the RB group had a detectable anti-HBs, and 99.0 and 99.3%, respectively, had anti-HBs ≥10 mIU/mL. The anti-HBs GMT was 113,201 mIU/mL in the EB and 16,623 mIU/mL in the RB groups (P < 0.0001). One year after the booster, 99.3% of subjects in the EB group and 100% in the RB group had detectable anti-HBs, and 97.9 and 98.5% respectively, had anti-HBs ≥10 mIU/mL. The anti-HBs GMT was 14,028 mIU/mL in the EB and 3437 mIU/mL in the RB group (P < 0.0001).
The immunity persists for at least 5 years after the primary vaccination with both pediatric vaccines in 99% of children vaccinated at the age of 8–10 years. It confirms that no booster is needed at that point.
From the *Institut National de Santé Publique du Québec, †Centre de Recherche du Centre Hospitalier Universitaire de Québec, ‡Ministère de la Santé et des Services Sociaux and §Université Laval, Québec, Canada
Accepted for publication September 13, 2004.
Supported in part by the Institut National de Santé Publique, the Ministry of Health and Social Affairs (Quebec, Canada) and GlaxoSmithKline.
Address for reprints: Bernard Duval, MD, 2400 d'Estimauville, Beauport, Québec, Canada G1E 7G9. Fax 418-666-2776; E-mail firstname.lastname@example.org.