Safety of a new conjugate meningococcal C vaccine in infants

Background-Group C conjugate meningococcal vaccines (Men C) were introduced into the UK primary immunisation schedule in November 1999. There has been extensive professional and public interest in their efficacy and safety. Aim-To determine the occurrence of at least one uncommon adverse event in i nfants related to the administration of the Chiron Men C vaccine. Methods-A total of 2796 infants aged approximately 2 months were recruited into the study from areas in and around Sheffield and from Scotland. They w ere vaccinated with the Chiron Men C vaccine at 2, 3, and 4 months along wi th routine immunisations. Data on adverse events occurring one month after each dose were collected actively and prospectively and reviewed for possib le relation to the vaccine. Results-There were no deaths. There were no serious adverse events consider ed definitely or probably caused by the vaccine. Four infants developed ser ious adverse events (hypotonia, screaming syndrome, maculopapular rash, and agitation, respectively) that were considered possibly related to the vacc ine. All recovered completely. Adverse events were seen in 1804 children bu t were considered possibly related to the vaccine in only 49 (1.8%). On sub sequent immunisation there were no recurrences of adverse events considered to be possibly related to the vaccine.