It has long been recognized that the positive effects of vaccination on childhood mortality cannot be solely attributed to a decline in the disease targeted by the vaccine. These so-called non-specific effects of vaccination have so far mostly been linked to mortality. However, it has been suggested that non-specific effects may also effect morbidity and nutritional status. This study aims to further explore the correlation between vaccination, susceptibility to infectious diseases (particularly malaria and bacterial infections), nutritional status and immunity.