RESULTS	Both groups had an appropriate response with regard to H. influenzae type b polysaccharide polyribosylribitol phosphate , but the dynamics of the response were significantly different : geometric mean concentrations ( micrograms per ml ) after the second , third and booster doses were 1.27 , 5.06 and 23.12 in the Pa group and 2.72 , 6.66 and 13.59 in the Pw group , respectively ( P = 0.0002 after second dose ; P = 0.0005 after booster ) .\