Seroprotective Titers against 2009 H1N1 Influenza A Virus after Vaccination in Allogeneic Hematopoietic Stem Cell Transplantation Recipients

Abstract

Little data are available regarding the safety and immunologic response to pandemic H1N1 influenza vaccine in recipients of allogeneic hematopoietic stem cell transplantation (HSCT). We measured serum antibody titers against A/California/7/2009 H1N1 using a hemagglutination inhibition assay in 82 allogeneic HSCT recipients who received the 2009 H1N1 vaccine between November 2009 and January 2010 after it became available at our institution. The median time between HSCT and vaccination was 19 months (range, 2.5–94 months), and the median time from vaccination to specimen collection was 56 days (range, 14–140 days). Seroprotective antibody titers (hemagglutination inhibition titer ≥1:40) against 2009 H1N1 influenza A virus were detected in 51% of patients. The presence of chronic graft-versus-host disease and type of conditioning regimen did not affect the rate of detection of seroprotective titers after vaccination. Patients were more likely to have a seroprotective titer the farther away from HSCT they were (adjusted odds ratio, 1.79 per year; 95% confidence interval, 1.12–2.85). Rituximab administration in the year before vaccination was associated with a lack of seroprotective titer (adjusted odds ratio, 0.11; 95% confidence interval, 0.01–0.97). The vaccine was safe and well tolerated. Strategies are needed to improve the influenza vaccine response in this population, especially those receiving immunotherapy.

Vaccination against pandemic H1N1 (2009) in patients after allogeneic hematopoietic stem cell transplantation: a retrospective analysis

“…We found a seroconversion and seroprotection rate of 42% (15/36), which is similar to rates reported on pandemic H1N1 (2009) vaccination in alloHSCT and autoHSCT patients by Issa et al [13] and Engelhard et al [15]. Previous studies of pandemic H1N1 (2009) vaccination in healthy people showed seroconversion in >90% within 21 days of vaccination [20,21].…”

“…Although Issa et al were not able to show a statistically significant influence of the presence of GvHD and concurrent immunosuppressive therapy (including prednisone) on the rate of seroprotection against pandemic H1N1 (2009) influenza virus, the trends were similar to our results: 59% of patients without GvHD had seroprotective titers, while 44% of those with aGvHD or cGvHD had seroprotective titers [13].…”

“…Issa et al [13] found lower rates of seroprotective titers to pandemic H1N1 (2009) vaccination in patients receiving mycophenolate mofetil.…”

“…Issa et al [13] described an increasing vaccination response rate in correlation with the length of the time span after transplantation, reflecting improved immunoreconstitution; however, the latter is also impaired by cGvHD [28].…”

“…Limited data are available on the immunologic responses to primary pandemic H1N1 (2009) infection and pandemic H1N1 (2009) vaccination in patients with hematologic malignancies in general and in HSCT recipients in particular [12][13][14][15]. Here, we present the results of a retrospective analysis of pandemic H1N1 (2009) vaccination response in alloHSCT recipients and its correlation with clinical and immunological characteristics.…”