535. Safety and immunogenicity of 2010-2011 H1N12009-containing trivalent inactivated influenza vaccine (TIV) in young children 12 to 59 months of age (YC) who received AS03-adjuvanted H1N12009 pandemic vaccine; a PHAC/CIHR (PCIRN) Influenza Research Network study
Session: Poster Abstract Session: Influenza Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
Background: 

During the influenza AH1N1 pandemic, a universal immunization program with monovalent oil-in-water (AS03) adjuvanted vaccine Arepanrix™ (GSK Biologicals) (AV) was offered in Canada. In the fall of 2010, there was concern that high levels of pre-existing pH1N1 immunity (due to vaccine or infection) could be associated with increased reactogenicity to 2010-2011 TIV.

Methods: 

YC immunized with 1 or 2 doses of AV (AV-1d and AV-2d), with or without 2009-10 TIV, received 1 or 2 doses of 2010-11 TIV in an open study in 5 Canadian centers. Blood was collected for serology on days 0, and 21 days post final TIV dose. Adverse events (AE) were collected days 0-6 by parent diary, a phonecall  for AE was conducted day 1 (when AE were expected to be at peak intensity) and at day 180.

Results: 

Enrolment of 207 YC began 7Sep10; day 1 safety data was given to public health 30Sep, prior to TIV programs. At baseline 99% of YC had A/H1N1 antibodies ≥10 mIU/ml and 85% a level of HAI ≥40 mIU/ml (95% CI 80, 90).Baseline geometric mean titres were higher in AV-2d than AV-1d recipients (153.1 (95%CI 126.2,185.7) v. 78.8 (95% CI 58.1- 106.8) p <0.001. Seroprotection to A H1N1 post TIV was achieved by 100% of vaccinees, and seroconversion (final titre ≥40mIU/ml if baseline titre <10 mIU/ml; final titre ≥ 4 times baseline titre if baseline ≥ 10mIU/ml) by 86.5 and 86.4% of AV-1d and AV-2d recipients, respectively 21 days post final TIV (95% CI 77.6, 92.8 and 78.9, 92, ns). Any local AE was reported by 53.6% (95% CI, 46.6, 60.6) post TIV dose 1 and by 62.5% (95% CI 40.6, 81.2) post TIV dose 2; one SAE (injection site) occurred. Any general AE was reported in 60.9% post dose 1, and in 58.3% post dose 2. No unsolicited SAE considered related to immunization, including seizures, were observed. No correlation of AE with serum responses (HAI ≥40 mIU/ml or not) was seen, but high pre-TIV AH1N1 antibodies were high in almost all YC.

Conclusion: 

YC who received AS03-adjuvanted AH1N12009 vaccine up to 11 months prior had high titres in the subsequent season, and 100% were seroprotected 21 days after TIV receipt. Acceptable rates of local and general reactogenicity occurred.

 


Subject Category: I. Adult and Pediatric Vaccines

Joanne Langley, MD, Canadian Center for Vaccinology, Dalhousie University and the IWK Health Centre, Halifax, NS, Canada, David W. Scheifele, MD, FIDSA, PHAC/CIHR Influenza Research Network, Vancouver, BC, Canada, Caroline Quach, MD MSc FRCPC, Pediatric Infectious Diseases and Medical Microbiology, The Montreal Children's Hospital, McGill University, Montreal, QC, Canada, Otto Vanderkooi, MD, Pediatrics, Microbiology and Infectious Diseases and Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada, Simon Dobson, MD, Vaccine Evaluation Centre, Vancouver, BC, Canada, Shelly McNeil, MD, Dalhousie University, Canadian Center for Vaccinology, IWK Health Centre, Halifax, NS, Canada, Donna MacKinnon-Cameron, MMath, Canadian Center for Vaccinology, IWK Health Centre, Halifax, NS, Canada, Brian Ward, MD, Infectious Diseases, McGill University, Montreal, QC, Canada, Susan Kuhn, MD, University of Calgary, Calgary, AB, Canada, Tobias Kollmann, MD, PhD, BC Children's Hospital and University of British Columbia, Vancouver, BC, Canada, Bruce Smith, PhD, Dalhousie University, Halifax, NS, Canada, Scott Halperin, MD, Dalhousie University, Canadian Center for Vaccinology, IWK Health Centre and Capital Health, Halifax, NS, Canada and James D. Kellner, MD, Pediatrics, University of Calgary and Alberta Health Services - Calgary Zone, Calgary, AB, Canada

Disclosures:

J. Langley, None

D. W. Scheifele, GSK Biologicals: Investigator, Research support

C. Quach, None

O. Vanderkooi, Pfizer: Investigator, Research grant

S. Dobson, GSK Biologicals: Investigator, Research grant

S. McNeil, sanofi pasteur: Grant Investigator, Research support
GSK: Grant Investigator, Research grant

D. MacKinnon-Cameron, None

B. Ward, GSK Biologicals: Grant Investigator, Research grant

S. Kuhn, GSK Biologicals: Investigator, Research grant

T. Kollmann, GSK Biologicals: Investigator, Research grant

B. Smith, None

S. Halperin, GSK Biologicals: Investigator, Research grant

J. D. Kellner, None

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