Trivalent, inactivated influenza virus vaccine in children with sickle cell disease

School-aged children with sickle cell disease who were administered a single dose of trivalent, inactivated influenza virus vaccine had serum antibody titers comparable to titers achieved in the two-dose trials carried out in 1978. The proportion exhibiting titers of 1:32 or greater ranged from 84% to 68% for the three antigens. Preschool children with sickle cell disease received two doses of the same vaccine four weeks apart and their postimmunization titers to each of the antigens were slightly lower. The vaccine, which contained 15 micrograms of hemagglutinin to each of three influenza viruses, A (H1N1), A (H3N2), and B, in a volume of 0.5 mL, was adequately immunogenic for schoolchildren who probably had been primed by previous natural infection. Younger children who received the same quantity in two divided doses four weeks apart had slightly lower but acceptable titers and tolerated the injections with few side reactions.