Antipolio prophylaxis of immunocompromised children during a nationwide oral poliovaccine campaign.

A nationwide vaccination campaign with oral poliovirus vaccine was organized in Finland in 1985 to halt an outbreak of poliomyelitis. Immunocompromised persons and their household contacts were excluded from the oral poliovirus vaccine target group and given instead a dose of inactivated poliovirus vaccine. This gave us an opportunity to determine whether immunocompromised persons are protected from poliomyelitis during an outbreak and oral poliovirus campaign. Fourteen children, ages 3 to 17 years, with leukemia were given a booster dose of a novel high antigen content, trivalent inactivated poliovirus vaccine. All but two responded by an at least 4-fold increase in serum-neutralizing antibodies to at least one poliovirus serotype. These results indicate that children with acute lymphocytic leukemia in remission respond well to a booster dose of inactivated poliovirus vaccine. Antibody concentrations to the uncommon local epidemic strain of type 3 poliovirus remained, however, relatively low in most patients (median, 1:6) suggesting relatively impaired heterologous response to vaccination. Possible spread of live vaccine viruses to the inactivated poliovirus-vaccinated children and their close contacts was evaluated by examining weekly fecal specimens from 20 children and their 19 regular adult contacts for cytopathic viruses. No polioviruses were isolated from 224 specimens examined, indicating that this high risk population was well-protected from unintended exposure to live polioviruses.