2009 Pandemic Influenza A H1N1 Vaccination In the Patients with Hematologic Malignancies: Requirement for Repeated Dosing to Optimize Seroprotection

• Published in: Blood 2010-11, Vol.116 (21), p.677-677
• Main Authors: de Lavallade, Hugues, Garland, Paula Lorraine, Sekine, Takuya, Hoschler, Katja, Marin, David, Stringaris, Kate, Loucaides, Eva, Howe, Katherine, Szydlo, Richard M., Kanfer, Edward J., McDonald, Donald, Kelleher, Peter, Cooper, Nichola, Khoder, Ahmad, Gabriel, Ian H, Alsuliman, Abdullah, Milojkovic, Dragana, Pavlu, Jiri, Goldman, John M., Apperley, Jane F., Rezvani, Katayoun
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V116.21.677.677

Abstract 677 In 2009 the spread of influenza A (H1N1) satisfied the World Health Organization (WHO) criteria for a global pandemic and led to the initiation of a vaccination campaign to ensure protection for the most vulnerable patients. However, the immunogenicity of the 2009 H1N1 vaccine in immunocompromised patients has not been specifically evaluated. Furthermore, the number of doses of vaccine required for effective immunization against H1N1 has not been established. Whereas the European Medicines Agency (EMEA) and the UK Department of Health (DoH) recommended the injection of two doses of inactivated H1N1 vaccine 3 weeks apart in immunocompromised individuals, the Centers for Disease Control and Prevention recommended immunization with one dose of inactivated H1N1 vaccine for patients with cancer receiving chemotherapy, followed by a booster vaccine after completion of treatment if the pandemic continued. The aim of this study was to determine the safety and efficacy of the 2009 H1N1 vaccine in patients with hematologic malignancies. We prospectively evaluated the humoral and cellular immune responses to monovalent influenza A/California/2009(H1N1)v-like strain surface antigen vaccine in 97 adults with hematologic malignancies and 25 adult controls. Patients received two intramuscular injections of the vaccine 21 days apart and controls received one dose. Antibody titers, expressed as geometric mean, were measured using a hemagglutination-inhibition assay on days 0, 21 and 49 after injection of the first dose. The induction of virus-specific T-cell responses by H1N1 vaccination was assessed directly ex-vivo by flow cytometric enumeration of antigen-specific CD8+ and CD4+ T-lymphocytes using an intracellular cytokine assay for IFN-γ and TNF-α production on days 0 and 49. Of the 97 patients, 32 had chronic myeloid leukemia (CML) in chronic phase in complete cytogenetic response on the tyrosine kinase inhibitors imatinib or dasatinib, 39 had a B-cell malignancy in complete remission (CR) or untreated, and 26 were recipients of allogeneic hematopoietic stem cell transplantation (allo-SCT) in CR at least 6 months beyond transplant and without evidence of graft versus host disease. The vaccine was well tolerated, with no obvious difference in side effects for patients and controls. By day 21 post-vaccination, protective antibody titers of 1:32 or more were seen in 100% of controls compared to 39% of patients with B-cell malignancies (p