BCG is often administered at birth in developing countries, so the observation that sensitisation to maternal schistosomiasis or filariasis in utero was associated with reduced interferon (IFN)-γ and increased interleukin (IL)-5 responses to mycobacterial antigens at one year of age, following BCG immunisation at birth, is of particular interest [4]. This evidence concerns the gene IFNG and schistosomiasis.