在90%以上儿童接种脊髓灰质炎灭活疫苗(IPV)、20年无脊髓灰质炎病例的芬兰,1984年却爆发了脊髓灰质炎流行。经鉴定该分离株是3型野毒株变异株(P3/芬兰/23127/84)。血清学分析提示,19岁以下儿童对该流行株的抗体水平比Saukett参考株低。Magrath等对接种IPV的芬兰、挪威、瑞典三个国家的儿童进行血清学分析亦得到相同结果。芬兰儿童血清对Saukett株的抗体几何平均滴度为1:25,面对流行株仅为1:4。动物试验证实,该流行株的纯化D抗原的免疫血清可中和同源病毒,但不能中和 More than 90% of children vaccinated against poliomyelitis (IPV), 20 years without poliomyelitis, polio erupted in 1984. The isolate was identified as a wild type strain of variant 3 (P3 / Finland / 23127/84). Serological analysis suggested that antibodies to this pandemic strain were lower in children under 19 years of age than the Saukett reference strain. Magrath and other serological analysis of children vaccinated with IPV in Finland, Norway and Sweden also obtained the same results. The geometric mean titer of antibody to Saukett strain in children from Finland is 1:25 and only 1: 4 against the prevailing strain. Animal tests confirmed that the epidemic strains of purified D antigen immune sera can neutralize homologous viruses, but can not be neutralized