Reactogenicity of a three-dose pertussis acellular vaccine catch-up in children 21-40 months of age

The reactogenicity of a three-dose catch-up acellular pertussis (aP) immunization of children at 21-40 months of age was evaluated. Vaccination was well-tolerated: fever greater than or equal to 38 degrees C was reported after 5% of administered doses and local reactions after 14-15%. The onset of adverse events was not associated with age at vaccination, interval between doses or previous presence of antibodies against pertussis, whereas injection in sites other than the buttock and presence of the same symptom after a previous dose were associated with higher reactogenicity. Because of the good safety profile of primary aP immunization in children > 1 year of age, catch-up vaccination campaigns could be considered in areas where pertussis whole-cell vaccination uptake has been low and where the number of susceptible children should be reduced to control pertussis circulation. (C) 1999 Elsevier Science Ltd. All rights reserved.