Despite the encouraging results on maternal immunization from Bangladesh, and the preliminary data supporting that TIV is efficacious mainly in HIV-infected non-pregnant adults, further data are needed to advocate for routine use of TIV during pregnancy in settings with a high prevalence of HIV. Reasons for this include that the impact of maternal HIV on the kinetics of TIV induced transplacental antibody transfer cannot be derived from available data. This is important as the primary focus of this proposal, and major potential public health benefit of maternal TIV vaccination, is targeted at protection of young infants. HIV infection is known to decrease placental integrity and lower antibody levels in the fetus and newborn. Furthermore, maternal hypergamma-globulinemia that is characteristic of HIV-infection may be associated with decreased neonatal antibody levels. This paradox is explained by the limited number of placental antibody receptors, resulting in immunoglobulin G (IgG) antibodies competing for available receptors and thereby decreasing vaccine-specific antibody transport. Preterm birth increases with HIV, chronic maternal disease or malnutrition. Transfer of maternal antibody which is gestational age dependant, may be more affected by maternal immunization in sub-Saharan Africa where these conditions are common.