Abstract
Vitamin A deficiency contributes to the morbidity and mortality from some infectious diseases. Empirical observations and trials from the early twentieth century led to the paradigm that improvement of vitamin A status could reduce morbidity and mortality among women and children. Many seminal observations of vitamin A deficiency and infection were made in Scandinavia. International organizations in the 1930s and 1940s emphasized adequate vitamin A status to prevent morbidity and mortality. With improvement of nutrition and hygiene in Europe and the United States, vitamin A deficiency largely disappeared, and attention later turned towards developing countries. Over one hundred clinical trials have addressed the impact of vitamin A on infectious disease morbidity and mortality and show that adequate vitamin A status is important in measles and diarrheal disease but not in non-measles pneumonia. Current studies extend investigations of the role of vitamin A to malaria, tuberculosis, and human immunodeficiency virus infection.