The likelihood of human-to-human transmission of H5N1 is “really lower,” Chowdhury claims. But when it were to manifest in a sustained fashion, it could rock the globe in a means not found Because the 1918 Spanish Flu. 5 to seven. For H5N1 amid birds, it can be about a hundred. https://www.dailypioneer.com/2015/potpourri/humbled-by-love-srk-gives-fan-to-fans-on-50th-birthday.html