Healthy children aged 5-17 months were randomized ( 1:1:1:1 ) to receive RTS , S/AS01 at 0-1-2 months from one of three commercial-scale purified antigen bulk lots ( 1600 litres-fermentation scale ; commercial-scale lots ) , or a comparator vaccine batch made from pilot-scale purified antigen bulk lot ( 20 litres-fermentation scale ; pilot-scale lot ) .