In three double-blind placebo-controlled trials of pneumococcal capsular polysaccharide vaccines against death from acute lower-respiratory-tract infections (ALRI), children were vaccinated at 6 months to 5 years of age. The efficacy of the vaccines against ALRI as the sole cause of death was estimated at 59% in children vaccinated when younger than 5 years (p = 0.008) and 50% in children vaccinated when younger than 2 years (p = 0.043). Mortality from all causes was 19% less in the vaccinated group.