Immune responses to influenza immunization in children receiving maintenance chemotherapy for acute lymphoblastic leukemia

Abstract

Purpose: To compare the immune responses to influenza vaccine in children with acute lymphoblastic leukemia (ALL) receiving maintenance chemotherapy with those in healthy children.

Methods: Hemagglutinin-inhibition (HAI) antibody titers were determined before and after influenza vaccination in children with ALL and healthy controls. Immune responses were measured as geometric mean titers (GMT) and 4-fold rises in HAI titers.

Results: Although post-immunization GMT were lower in children with ALL compared to healthy children for the H1N1 antigen (P<0.001), the H3N2 antigen (P=0.03), and for the influenza B antigen (P=0.003), at least 60% of children with ALL had at least a 4-fold rise in HAI titers to each of the influenza antigens.

Conclusions: While the GMT after trivalent influenza immunization in children with ALL were significantly lower than those seen in healthy children, the majority of children with ALL had 4-fold rises in HAI titers. Children receiving maintenance chemotherapy for ALL should receive yearly influenza vaccine.