- Aim 2. Characterize the post-vaccine impact of HBV on OMIC and immune signatures in vivo that predict immunogenicity of HBV in human newborns. In adults, analysis of vaccine-induced signatures (i.e. post-vaccine) has provided new insights for several vaccines, including HBV. The investigators will for the first time apply this approach to newborns and expand it by manipulating the neonatal response to HBV in vivo by co-administering BCG, as it substantially changes immunogenicity of HBV thereby testing cause-effect relationships in vivo. For Aim 2 the investigators will characterize whole blood gene expression and the plasma and leukocyte proteome as well as white blood cell composition and functional status at Days 1, -3 and -7 postvaccine contrasting infants that received nothing (delayed vaccines to 7 days of age), HBV, BCG or (HBV + BCG) at birth and correlate this with anti-HBs titers.