Immunogenicity of pandemic (H1N1) 2009 vaccine in children with cancer in the United Kingdom.
BACKGROUND
Children with cancer have an increased susceptibility to influenza infection. The objective of this study was to assess the immunogenicity of pandemic (H1N1) 2009 vaccine in children with cancer.


METHODS
Children were recruited from the Royal Marsden Hospital, England, during November 2009. The vaccination schedule consisted of 2 doses of an AS03(B)-adjuvanted vaccine given at days 0 and 21. Serological analysis was performed on blood samples obtained at day 0 and day 42. The primary immunological end point was the seroconversion rate, which was defined as the proportion of subjects with an individual 4-fold increase in hemagglutination inhibition titer and a postvaccination hemagglutination inhibition titer ≥1:32.


RESULTS
Fifty-four children with a median age of 6.3 years (range, 1.4-16.6 years) were vaccinated and had samples taken for serological analysis. Twenty-four (44.4%) of 54 children demonstrated seroconversion. Seroconversion rates were 33.3% (9 of 27) among children with acute lymphoblastic leukemia, 36.4% (4 of 11) among those with lymphoma or other leukemias, 66.7% (6 of 9) among those with brain tumors, and 71.4% (5 of 7) among those with other solid tumors. Seroconversion occurred in 4 (28.6%) of 14 children receiving acute lymphoblastic leukemia maintenance therapy. Univariate analysis showed significantly higher responses among children with solid tumors, compared with those with hematological malignancies (11 [68.8%] of 16 vs 13 [34.2%] of 38; P = .03), and among those not receiving treatment, compared with those receiving treatment (7 [87.5%] of 8 vs 17 [37.0%] of 46; P = .02). Multivariable analysis showed that age, cancer type, and lymphopenia did not influence seroconversion rates.


CONCLUSIONS
These data suggest that this AS03(B)-adjuvanted pandemic (H1N1) 2009 vaccine can induce limited but useful protective immune responses in children with cancer.
Dept of Child Health, St George's, University of London, London, England. jbate@sgul.ac.uk
Jessica
J
Bate
Chee-Fu
CF
Yung
Katja
K
Hoschler
Liz
L
Sheasby
James
J
Morden
Mary
M
Taj
Paul T
PT
Heath
Elizabeth
E
Miller
D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004338:Drug Combinations; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D008297:Male; D009369:Neoplasms / Q000276:immunology*; D011136:Polysorbates / Q000008:administration & dosage; D013185:Squalene / Q000008:administration & dosage; D006113:United Kingdom; D014611:Vaccination / Q000379:methods; D024502:alpha-Tocopherol / Q000008:administration & dosage
D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D004338:Drug Combinations; D007252:Influenza Vaccines; D011136:Polysorbates; D013185:Squalene; C550253:AS03 adjuvant; D024502:alpha-Tocopherol