TY - JOUR T1 - New combination vaccines still need a boost JF - Archives of Disease in Childhood JO - Arch Dis Child SP - 1 LP - 2 DO - 10.1136/adc.2006.106724 VL - 92 IS - 1 AU - A J Pollard Y1 - 2007/01/01 UR - http://adc.bmj.com/content/92/1/1.1.abstract N2 - Perspective on the paper by Kitchin et al (see page 11) Pertussis vaccination is part of the backbone of global immunisation policy because of the high rates of disease in unimmunised populations and a mortality in early infancy of about 1 in 500. Most of the world’s children are immunised with whole-cell pertussis vaccines, which were used in the UK from the 1950s and have been highly effective in reducing pertussis-related morbidity and mortality. Whole-cell pertussis vaccines contain >3000 pertussis proteins as a suspension of killed organisms, can cause severe local reactions, and are associated with inconsolable crying and hospitalisations related to febrile seizures or hypotonic hyporesponsive episodes (HHE) after immunisation in infants. By contrast, acellular pertussis vaccines, containing ⩽5 purified proteins (components) from Bordetella pertussis, are far less reactogenic than whole-cell pertussis vaccines. The decision to replace whole-cell pertussis vaccine in the UK schedule with Pediacel (DTaP–IPV–Hib; Sanofi Pasteur, Lyon, France) in 2004 was good news for infants, as it has an improved reactogenicity profile when compared with whole-cell pertussis vaccines,1 and can be expected to lead to a marked reduction in these unpleasant severe adverse events. A similar acellular pertussis vaccine, Pentacel (DTaP–IPV–Hib), also manufactured by Sanofi Pasteur, was shown to reduce HHE-related hospitalisations by 67% and febrile seizures by 79% after introduction in Canada in the late 1990s.2 The efficacy of new pertussis-containing vaccines is difficult to evaluate in immunised populations, and protection cannot be adequately assessed using immunogenicity measures alone, as serological correlates of protection are not clear.3 In addition to Pediacel, which contains five purified pertussis proteins, there are several other acellular pertussis vaccines available, with varying numbers of components and doses of proteins in them. Extrapolation from previous studies using similar vaccines is necessary in considering whether Pediacel might … ER -