[Efficacy and safety of the Brazilian vaccine against hepatitis B in newborns].

OBJECTIVE To analyze the efficacy and safety of a recombinant Hepatitis B vaccine in newborns. METHODS The study was carried out in a general hospital in the city of Guarulhos, Southeastern Brazil, between 2002 and 2005. The recombinant Hepatitis B vaccine from Instituto Butantan (VrHB-IB) was tested in two clinical trials. In both trials, newborns were randomly allocated to the experimental or control (reference vaccine) groups. Newborns were given three doses of vaccine, one up to 24 hours after birth and the other two 30 and 180 days later. In the first trial, 538 newborns completed the immunization protocol, and 486 in the second. Vaccines were considered equivalent when seroprotection difference was below 5%. RESULTS Seroprotection in the first trial (anti-HBs > or = 10mUI/ml) was 92.5% (247/267) in the experimental group, compared to 98.5% (267/271) in the control (p = 0.001). With this result, VrHB-IB did not fulfill the pre-established criterion for equivalence. After increasing the concentration of antigen in the vaccine to 25 microg, seroprotection reached 100% in the experimental group and 99.2% in the control. No severe adverse effects were recorded. CONCLUSIONS The reformulated VrHB-IB is considered equivalent to the reference vaccine, and its use is recommended in newborns.