[Hexavalent combined vaccination]

Since January 2004, hexavalent combined vaccines are available in Belgium. They protect children simultaneously against 6 diseases (poliomyelitis, diphtheria, tetanus, pertussis, invasive infections with Haemophilus influenzae type b and hepatitis B) and reduce the number of needed injections. Acellular pertussis vaccine is the corner-stone of the combination. Theoretically, only 5 visits and 6 injections are needed to complete the vaccination of the children. In addition to the reduction of injections and consequently a better comfort for the child, Hexavalent vaccination favours an increase of immunization coverage, alleviation of the burden of diseases evitable by vaccination, simplification of immunisation programme and diminution of their cost. However an increased surveillance of the incidence of the diseases, particularly for pertussis and invasive Haemophilus influenzae type b disease is needed. As always for a new product, pharmacovigilance has to be able to detect any severe adverse event. Parent's information must be strengthened to maintain confidence in the immunization programme. Medical practice will have to adapt to the new vaccine because it reduces individual flexibility and modifies the catch-up immunization schedule.