The proposed trial will be conducted within the Entebbe Mother and Baby Study (EMaBS) clinic in collaboration with the Entebbe Hospital located within the same environs. The EMaBS birth cohort was established in 2002 to investigate the effects of helminths and their treatment on immune responses to vaccines and on susceptibility to infectious and allergy-related diseases. EMaBS is under the Immunomodulation and Vaccines (I-Vac) programme of the MRC/UVRI and LSHTM Uganda Research Unit. They have a long-standing interest in improving the understanding of BCG immunisation in tropical settings and have carried out several studies on BCG. These include investigating the impact of maternal worm infections on the infant immune response to BCG, and the effects of maternal latent tuberculosis infection on the immune response to BCG in infants. They have also compared the immunogenicity of different BCG strains and examined the non-specific benefits of BCG immunisation.