<p>THE INTRODUCTION of the new childhood vaccine in September 2004 is a welcome development in the immunisation programme. Instead of having an injection which gives protection against diphtheria, tetanus, pertussis and Haemophilus influenzae type b (HIb), and a separate live poliovirus vaccine administered by mouth, infants are given all five vaccines combined in one injection as DTaP/IPV/Hib. The new vaccine contains the inactivated poliovirus vaccine (IPV). Fewer antigens are used in the acellular pertussis component giving less minor side effects, particularly in older babies and children. Children will also receive IPV combined with the other injectable vaccines: low-dose diphtheria, acellular pertussis and inactivated polio as dTaP/IPV for a pre-school booster, and tetanus, low-dose diphtheria and inactivated polio as Td/IPV for a teenage booster. The changes are possible because of developments in vaccine technology and changing patterns of disease.</p>