In the priming phase of the trial 509 infants were randomised in a 10:10:7:4 ratio into four groups to receive either a single MenC-cross reacting material 197 ( CRM ) dose at 3 months ; two doses of MenC-CRM at 3 and 4 months ; a single MenC-polysaccharide-tetanus toxoid ( TT ) dose at 3 months ; or no MenC doses , respectively .