Immunity after (re)vaccination of paediatric patients following haematopoietic stem cell transplantation

Aims:  Loss of specific immunity follows allogeneic haematopoietic stem cell transplantation (HSCT) in the majority of cases. Responses to (re)vaccinations can be used as indicators of a functional immunological recovery. Methods:  Twenty-three paediatric recipients of HSCT were enrolled in a single centre setting and responses to scheduled immunizations analysed. Results:  Immunity to vaccine-preventable diseases was impaired post HSCT, but (re)vaccinations induced protective responses in 59–100%, depending on the vaccine, regardless of prior graft-versus-host disease (GVHD) history. Conclusion:  Despite the marked impact of moderate to severe chronic prior GVHD on both the qualitative and quantitative T-cell recovery post allogenic HSCT, most paediatric recipients of allogeneic stem cell grafts appear to attain protective antibody levels after immunization.