Poliovaccine virus in the cerebrospinal fluid after oral polio vaccination.

In February-March 1985 an oral poliovirus vaccine campaign was launched in Finland in a population vaccinated earlier with inactivated poliovaccine. During this campaign a strain of poliovirus was isolated from the cerebrospinal fluid (CSF) of a 7-year-old girl 34 days after she had received oral poliovirus vaccine. She had long-lasting headache, vomiting and fever but no paralysis. This case demonstrates that poliovaccine virus can invade the central nervous system even after a complete course of inactivated poliovirus vaccine if the inactivated vaccine has been poorly antigenic against one of the three types of virus.