Pertussis vaccination.

With 3.2 serious events per million doses, the risks associated with pertussis vaccination are greater than for any other routine immunization. The most significant side effects are neurologic, but these are rare when compared with the neurologic effects of pertussis infection itself. High fever, persistent or high-pitched cry, seizures, encephalopathy and shock are absolute contraindications to further pertussis vaccination. A new acellular vaccine shows promise.