Repeated vaccination is required to optimize seroprotection against H1N1 in the immunocompromised host

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BlankHaematologica, Vol 96, Issue 2, 307-314 doi:10.3324/haematol.2010.032664

Repeated vaccination is required to optimize seroprotection against H1N1 in the

immunocompromised host

Hugues de Lavallade1, a Garland2,*, Takuya Sekine1,*, Katja Hoschler3,

Marin1, Kate Stringaris1, Eva Loucaides1, Howe1, Szydlo1, Ed

Kanfer2, Macdonald2, Kelleher4, Nichola 2, Ahmad Khoder1, Ian

H. 1, Dragana Milojkovic2, Jiri Pavlu2, M. Goldman1, Jane F.

Apperley1, Katayoun Rezvani1

1 Department of Haematology, Imperial College, London

2 Department of Haematology, Imperial College Healthcare NHS Trust, London

3 Respiratory Virus Unit, Health Protection Agency Centre for Infections, London

and

4 Department of Immunology, Chelsea and Westminster Hospital, Imperial College

Healthcare NHS Trust, London, UK

Correspondence: Katayoun Rezvani, Department of Haematology, Imperial College,

Hammersmith Campus, 4th Floor Commonwealth Building, Du Cane Road, London W12

0NN, UK. Phone: international +44.208.3832175. Fax: international

+44.203.3138223. E-mail: k.rezvani@...

Background: In 2009 the declaration by the World Health Organization of a global

pandemic of influenza-H1N1 virus led to a vaccination campaign to ensure

protection for immunocompromised patients. The goal of this study was to

determine the efficacy of the 2009 H1N1 vaccine in patients with hematologic

malignancies.

Design and Methods: We evaluated humoral and cellular immune responses to 2009

H1N1 vaccine in 97 adults with hematologic malignancies and compared these

responses with those in 25 adult controls. Patients received two injections of

vaccine 21 days apart and the controls received one dose. Antibody titers were

measured using a hemagglutination-inhibition assay on days 0, 21 and 49 after

injection of the first dose. Cellular immune responses to H1N1 were determined

on days 0 and 49.

Results: 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<0.001), 46% of allogeneic stem cell transplant recipients

(P<0.001) and 85% of patients with chronic myeloid leukemia (P=0.086). After a

second dose, seroprotection rates increased to 68%, (P=0.008), 73%, (P=0.031),

and 95% (P=0.5) in patients with B-cell malignancies, after allogeneic stem cell

transplantation and with chronic myeloid leukemia, respectively. On the other

hand, T-cell responses to H1N1 vaccine were not significantly different between

patients and controls.

Conclusions: These data demonstrate the efficacy of H1N1 vaccine in most

patients with hematologic malignancies and support the recommendation for the

administration of two doses of vaccine in immunocompromised patients. These

results may contribute towards the development of evidence-based guidelines for

influenza vaccination in such patients in the future.