Abstract
A total of 49 children with acute lymphoblastic leukemia were immunized with a purified subvirion trivalent influenza vaccine (Wyeth-USA) and monitored for hemagglutination inhibition (HI) and neuraminidase inhibition (NI) antibodies before vaccination, and then three weeks and six months after vaccination. Results for HI antibodies were evaluated as geometric mean titre (GMT), mean fold antibody increase (MFI), protection and response rates and those for NI antibodies as geometric mean titre (GMT) and mean fold antibody increase (MFI). Six months after vaccination GMT for hemagglutinin 1 (HI) was much higher than previous values. GMT for hemagglutinin 3 (H3) and hemagglutinin B (HB) was lower than three weeks after vaccination, but much higher than the original values. In the control group GMT for H1 was on a low level all the time and for H3 and HB it was lower when compared with the original values. The proportion of vaccines to antibodies ±40 ranged between 45% and 88%. Six months after vaccination GMT for neuraminidase 1 (NI) increased when compared with the second sampling; for neuraminidase 2 (N2) and neuraminidase B (NB) it was slightly lower. In the control group GMT for all antigens was on a low level all the time. The results point to a significant seroconversion for both components after vaccination when compared with the control group.