Severe measles: a reappraisal of the role of nutrition, overcrowding and virus dose.

The factors predisposing to severe measles, which accounts for a considerable fraction of the high infant and child mortality in the third world, are re-examined. The conviction that protein-energy-malnutrition (PEM) aggravates measles is challenged by findings of prospective community-based studies. It was found that severe measles was not associated with PEM but frequently accompanied overcrowding in Guinea-Bissau. Secondary cases fared worse than index patients. Among adequately nourished hospitalised African children, immunological and radiological parameters, together with the effects of age and HLA antigens, were closely related to sickness and death in measles. This variation in case fatality rate does not appear to be simply explained by age-dependent host reactions or differences in medical care. The hypothesis which fits most of the observed facts postulates that the transmission of a large inoculum of virus particles to susceptible children is an important cause of severe disease. The implication of this interpretation is that specific measles control, and not only improvements in nutrition, is important in high risk areas for a reduction of measles mortality. It is further suggested that health policy should promote those social changes which limit intense exposure to measles virus.