Marennikova S S, Macevic G R
Bull World Health Organ. 1975;52(1):51-6.
In experiments on rabbits it was found that although administration of inactivated smallpox vaccine did not induce a demonstrable antibody response in the serum it enhanced the immune response to subsequent inoculation with live vaccine. The dose of inactivated vaccine corresponded to 8 x 10(7) PFU before inactivation (by (60)Co gamma-radiation); the dose of live vaccine was 1.2 x 10(5) PFU. When the interval between the two inoculations was 7-days, virus-neutralizing antibody appeared after 5 days and reached levels 2-4 times those obtained with live vaccine alone. With longer intervals (up to 60 days) the enhancement of the immune response was even greater. It seems likely that use of the two-step method may reduce the incidence of post-vaccination encephalitis and clinical studies to determine the optimum conditions for safety and efficacy are at present being undertaken.
在对兔子的实验中发现，尽管接种灭活天花疫苗未在血清中诱导出可检测到的抗体反应，但它增强了对随后接种活疫苗的免疫反应。灭活疫苗的剂量相当于灭活前（通过钴-60γ射线）8×10⁷ PFU；活疫苗的剂量为1.2×10⁵ PFU。当两次接种的间隔为7天时，5天后出现病毒中和抗体，其水平达到单独接种活疫苗时的2至4倍。间隔时间更长（长达60天）时，免疫反应的增强更为明显。两步法的使用似乎有可能降低接种后脑炎的发生率，目前正在进行临床研究以确定安全性和有效性的最佳条件。
