Combination vaccines including antigens for immunising against diphtheria, tetanus, pertussis and Hib are known ("DTP-Hib" vaccines). The invention addresses the need for such vaccines with low doses of Hib antigen, to reduce cost, that do not require reconstitution in the field. Thus the invention provides a combination vaccine comprising antigens for protecting a subject against at least diphtheria, tetanus, pertussis and Hib, wherein: (a) the antigen for protecting against Hib is a conjugate of a Hib capsular saccharide (b) the concentration of the Hib conjugate in the vaccine is <15 μg/ml and (c) the Hib conjugate has never been lyophilised. Vaccines of the invention have been found to be safe and to be highly immunogenic.
