Safety and immunogenicity of hepatitis B vaccine administered into ventrogluteal vs. anterolateral thigh sites in infants: a randomised controlled trial.

Lowered immune response to hepatitis B vaccines has been found in individuals vaccinated into dorsogluteal site compared to vastus lateralis thigh muscle.The aim of this study was to compare the immunogenicity and reactogenicity of a hepatitis B vaccine in infants vaccinated into ventrogluteal or anterolateral thigh sites.Randomised controlled trial.The recruitment of study participants was carried out from February to November 2007 in the five maternity hospitals located in the eastern region of Goiânia City, Central Brazil. Newborns up to 12h old weighing at least 2.5 kg were enrolled in the study.A total of 580 newborns were randomised to receive three hepatitis B vaccine doses into ventrogluteal (n=286) or anterolateral thigh (n=294) sites. Of them, 474 (81.7%) completed the study: 224 from the ventrogluteal group (intervention group) and 250 from the anterolateral thigh group (control group). Fever and local adverse events were evaluated 48 h after each vaccine dose. Blood samples (3 mL) were collected between 45 and 60 days after the third vaccine dose, and anti-HBs antibody titres were determined by automatic analysis using the Microparticle Immunoenzymatic Test (AxSYM Ausab, Abbott, Germany).The groups did not differ by gender, weight, length of time between vaccine doses, or maternal characteristics. The proportion of infants who developed protective anti-HB titres after full vaccination into the ventrogluteal site was 97.8% (95% confidence interval [CI]: 94.8-99.3; geometric mean titre: 427.5 mIU/mL; 95% CI: 344.9-530.0), similar to that of infants vaccinated into the anterolateral thigh site (97.6%; 95% CI: 94.8-99.1; geometric mean titre: 572.0 mIU/mL; 95% CI: 471.1-694.6). No complication was found after 1503 vaccine doses, but a lower proportion of fever and local adverse events was found among the intervention group (17.9%) vs. the control group (23.7%) (p<0.01).Our results suggest that the ventrogluteal region is a suitable site for intramuscular injection in infants, particularly for the hepatitis B vaccine.