The invention relates to a method for producing the flu virus according to which:a. a flu vaccine is administered to hens,b. the eggs are taken from the immunized hens,c. the embryogenesis process is triggered,d. the embryonated eggs are infected by inoculating a flu virus into the allantoic cavity,e. the infected embryonated eggs are incubated under temperature and humidity conditions which allow replication of the virus, andf. the allantoic fluid containing the virus is harvested.本發明係關於一種產生流感病毒之方法,其中:a.向母雞投與流感疫苗,b.自該等免疫之母雞取得蛋,c.觸發胚胎發生過程,d.藉由將流感病毒接種至尿囊腔中來感染該等含胚蛋,e.受感染之含胚蛋在允許病毒複製之溫度及濕度條件下培養,及f.收穫含有病毒之尿囊液。