We conducted a randomized, double-blind clinical trial of an experimental mammalian cell-derived
DNA hepatitis B vaccine (
Betagen, Connaught Laboratories Ltd, Toronto, Canada) to determine its efficacy in infants born to mothers who were carriers of
hepatitis B surface antigen (
HBsAg). Four groups of 55 infants received
injections as follows: (1) a licensed plasma-derived
vaccine (Lanzhou, Lanzhou Institute for Biological Products, Lanzhou, People's Republic of China), 20 micrograms; (2)
Betagen, 20 micrograms; (3)
Betagen, 20 micrograms+hepatitis B
immune globulin (
HBIG); and (4)
Betagen, 10 micrograms+HBIG.
Vaccine injections were given at birth and at 1 and 6 months and
HBIG was given at birth. The
vaccines were compared to a historical placebo control group. The efficacy of
Betagen alone was 82.6% compared to 51.0% for the Lanzhou. Efficacy of
Betagen increased with the concomitant use of
HBIG. No infants who were
HBsAg negative at birth and/or were born to
hepatitis B e antigen (
HBeAg) negative mothers became carriers. The rate of
HBsAg in infants receiving
Betagen alone, and born to mothers who were
HBeAg positive, decreased from 60% at birth to 20% by the ninth month, compared to 62.5% and 50% (respectively) for Lanzhou. The percentage of infants with protective levels of antiHBs was significantly higher for
Betagen alone than for Lanzhou, but the geometric mean titre of antiHBs for responders was not significantly different. We have shown that
Betagen alone is highly efficacious in preventing the development of
hepatitis B in infants born to mothers who are carriers of
HBsAg and is also highly effective in reducing the carriage of
HBsAg in infants who are
HBsAg positive at birth and/or born to
HBeAg positive mothers.