537. Children with Cancer Have Impaired Neutralization Responses to Influenza Vaccine
Session: Poster Abstract Session: Influenza Vaccines
Friday, October 21, 2011
Room: Poster Hall B1

Background: Influenza vaccination is recommended for immunocompromised persons. The most appropriate immune correlate to assess vaccine responses in this population is unclear. We compared immune responses to monovalent 2009 pandemic influenza vaccine by two commonly used assays to assess how neutralization responses might differ in children with high risk medical conditions.

Methods: Children (6 months-21 years) with cancer, HIV infection, or sickle cell disease (SCD) received 1 or 2 doses of monovalent H1N1 influenza vaccine (H1N1 MIV). Hemagglutination inhibition (HI) and microneutralization (MN) antibody titers were measured against 2009 H1N1 influenza A virus 1 month after each dose and 6 months after the last dose.

Results: 103 subjects were enrolled and 99 were evaluable (39 with HIV, 37 with cancer, and 23 with SCD). Mean age (+/-SD) of cancer participants was 7.9 (+/-5.4) years. Mean age (+/-SD) of participants with HIV was 18.0 (+/-3.5) years. Mean age (+/-SD) of participants with SCD was 13.3 (+/-4.2) years. 54% were males; 65% black; and 96% also received seasonal influenza vaccine. In the participants with SCD, the post-vaccination geometric mean titer (GMT) was 329.8 (95%CI, 270.6-402.0) by HAI and 1577.4 (95%CI 1116.6-2228.4) by MN. In HIV-infected subjects, GMT was 92.6 (95%CI, 81.2-105.5) by HAI and 377.1 (95%CI 285.9-515.9) by MN. In children with cancer, GMT was 36.4 (95%CI, 30.1-44.1) by HAI and 47.3 (95%CI, 33.2-67.4) by MN. The ratio of MN to HAI was 4.8 for SCD, 4.1 for HIV, but only 1.3 for children with cancer (Figure). Although HAI titers remained stable 6 months post-vaccination, MN responses decayed such that MN to HAI ratios were 1.3, 1.0, and 0.5 for SCD, HIV, and cancer, respectively.

Conclusion: Neutralization responses in immunocompetent children with SCD are robust 1 month after vaccination compared to antibody titers measured by HAI, but decrease within 6 months. Neutralization responses in children with HIV were lower overall than in children with SCD, but a normal MN to HAI ratio was maintained. Children with cancer have impaired neutralization as assessed either by absolute values or in comparison to HAI.


Subject Category: E. Innate and adaptive immunity to infections, including vaccine immunology

Lee-Ann Van De Velde, BBiomedSc(Hons), Hana Hakim, MD, MS, Patricia Flynn, MD and Jonathan A. McCullers, MD, St. Jude Children's Research Hospital, Memphis, TN

Disclosures:

L. A. Van De Velde, None

H. Hakim, None

P. Flynn, Bristol Myers Squibb: Research Contractor, Research support
Tibotec: Research Contractor, Research support

J. A. McCullers, AVIBioPharma: Consultant, Consulting fee
GlaxoSmithKline: Consultant, Consulting fee
Novartis: Consultant, Consulting fee
Pfizer: Consultant, Consulting fee

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