Acute respiratory infections.

During the past decade, recognition of the significance of pneumonia for childhood mortality has greatly increased. Etiologic studies have clarified the role of Streptococcus pneumoniae and H. influenzae as the pathogens most responsible for childhood pneumonia in developing countries. Case management intervention strategies using community health workers to identify cases of pneumonia by counting respiratory rate and observing chest indrawing have been shown to reduce ARI-related mortality. Although research is underway to develop more effective vaccines against Streptococcus pneumoniae and non-type b H. influenzae, effective case management will remain the most realistic method of reducing mortality in the next decade. Important gaps remain in our understanding of the pathogenesis, etiology, and epidemiology of acute respiratory infections. Our understanding is complicated by the multiplicity of viral and bacterial agents and their interrelationships, by an abundance of interacting host risk factors, and by diverse social, cultural, and environmental factors. However, sufficient knowledge is available to support the implementation of the WHO case management intervention strategies, which will save the lives of the many children now dying because of pneumonia.