Antibody Response to a Haemophilus influenzae Type b Polysaccharide Tetanus Toxoid Conjugate Vaccine in Splenectomized Children and Adolescents

Abstract

20 children and adolescents 4–18 years old and Splenectomized for various reasons (spherocytosis (n = 6), idiopathic thrombocytopenia (n = 8), other (n = 6)) were immunized once with a Haemophilus influenzae type b (Hib) polysaccharide tetanus toxoid conjugate vaccine. Prior to vaccination 10/20 patients had anticapsular antibodies below what could be considered the minimum protective level in splenectomized (0.6 μg/ml), whereas all obtained high antibody levels after vaccination. In addition 1 infant with congenital asplenia was vaccinated at 2,4 and 6 months of age, and was shown to respond well after the second and third injection with serum antibody concentrations of 0.84 and 10.7 μg/ml respectively. Because asplenic individuals have an increased risk of invasive Hib infection, these data suggest that vaccination of such individuals against Hib may be justified.