• toxoids from the bacteria that cause diphtheria and tetanus; • killed whole B. pertussis; • polysaccharides extracted from the ‘ capsules’ that surround the bacterium Hib - the polysaccharides are chemically attached (conjugated) to tetanus toxoid as a carrier protein because this improves the response to the vaccine; 7 Westferry Circus, Canary Wharf, London E14 4HB, UK Tel.