Volume 15, Number 3—March 2009
Meeting the Challenge of Influenza Pandemic Preparedness in Developing Countries
|Case-fatality rate, %
||Reduction in no. deaths, %||Total sample size (power)
*1:1 randomization of persons to the 2 treatment groups, α = 0.05 (2-sided), χ2 test (continuity corrected). The example shown assumes a case-fatality rate of 50%, which is similar to what has been seen for patients infected with influenza virus A (H5N1). If a new pandemic virus is associated with a lower case-fatality rate, sample sizes required to show similar reductions in case-fatality rates would have to be larger.