Salk has realised between 1951 and 1953 vaccination trials against flu on 18000 soldiers with incomplete Freund adjuvant and compared to 22000 soldiers vaccinated with classical formulation.

• 美国细菌学家索尔克在1951到1953年间开展了一项流感疫苗试验：用弗氏不完全佐剂给18000名士兵接种，用传统配方给22000名士兵接种。