London , march 5 ( reuters ) - an experimental bird flu vaccine for humans provides substantial cross - immunity against " drifted " strains of the virus , suggesting it may provide protection in the event of a pandemic , its maker said on monday 倫敦(路透社) 3月5日-一種人用禽流感疫苗經(jīng)過實驗證實具有免疫能力能對抗“漂浮”病毒菌株,它的發(fā)明者星期一發(fā)表報道說此疫苗可以提供保護以預(yù)防禽流感的流行。