Successful H1N1 influenza vaccination of children receiving chemotherapy for solid tumors.

Background: The hemato-oncology community has been seriously concerned about the H1N1 pandemic of 2009. Here, we report on the evaluation of the immunogenicity and tolerability of H1N1v monovalent vaccines in young patients with cancer during this pandemic.

Procedure: Between December 7, 2009 and February 26, 2010, 20 children receiving chemotherapy for solid tumors at the Institute of Hematology and Pediatric Oncology of Lyon, were immunized by 2 doses of either AS03-adjuvanted or nonadjuvanted vaccine. The level of specific antibodies was assessed at D21 and D42.

Results: Seroconversion was observed in 13 of the 20 cases (65%), and 18 of 20 cases (90%) had protective titers after the 2 doses. Exploratory univariate analysis failed to show a significant influence of prevaccination lymphocyte counts on seroresponse rates.

Conclusions: These data suggest that H1N1v monovalent vaccines were well tolerated by young cancer patients while on chemotherapy and achieved protective immune response in most cases.