Sickle Cell Disease.

To the Editor: Isanaka and colleagues (March 23 issue) 1 tested a heat-stable rotavirus vaccine in Niger and report an efficacy of 66.7% against severe rotavirus gastroenteritis in the per-protocol population.The purpose of rotavirus vaccination is ultimately to reduce the incidence of diarrhea and diarrhea-related death.However, the rate of severe gastroenteritis due to any cause was not significantly lower among the vaccinated infants than among those who received placebo (difference in rate, 1.97 cases per 100 personyears; 95% confidence interval [CI], -1.28 to 5.22).The lack of efficacy against severe gastroenteritis has not been highlighted in the discussion although this information is crucial for…