However , in children and older infants , a second dose of conjugate vaccine had no incremental effect on antibody titres and , at all ages , concentrations of antibodies increased substantially @ months after vaccination ( from @ U/mL -LSB- @-@ -RSB- to @ U/mL -LSB- @-@ -RSB- in adults , from @ U/mL -LSB- @-@ -RSB- to @ U/mL -LSB- @-@ -RSB- in children , and from @ U/mL -LSB- @-@ -RSB- to @ U/mL -LSB- @-@ -RSB- in older infants ) .