Two doses of a recombinant Lyme disease vaccine (15 and 30 mug) were admini
stered to children 2-5 years old (0-1-month schedule) and were well tolerat
ed. Both doses were highly immunogenic with geometric mean titers 1 month a
fter vaccination of 4366 and 9877 ELISA units (EU)/mL, respectively. Nearly
all subjects had antibody levels of greater than or equal to 1400 EU/mL, s
uggesting protective tick titre for one tick season.