titre iii: influenza b immunogenicity investigation

Conditions: Influenza

Summary: each winter, viruses belonging to two kinds of influenza a ("a/h1n1" \& "a/h3n2") and two kinds of influenza b ("b/yamagata" \& "b/victoria") can cause illness. historically, the yearly influenza vaccine that was recommended in children was designed to protect against both kinds of influenza a but only one kind of influenza b. in a series of trials conducted between 2008-09 and 2010-11 (titre i, ii, and iib), the titre investigators measured antibody response to influenza b in children who were primed with two doses of trivalent inactivated influenza vaccine (tiv) containing b/yamagata. overall, the investigators found that 2 doses of vaccine containing b/yamagata did not adequately prime children for response to the alternate b/victoria antigen and that subsequent vaccine doses containing b/victoria-lineage antigen strongly boosted antibodies to the b/yamagata antigen that was introduced during first immunization priming, but with lower responses to b/victoria. for the first time since 2009-10, the recommended b/victoria component of the seasonal influenza vaccine has been changed, from b/brisbane/60/2008 to b/colorado/60/2007 for the coming 2018-19 season. the investigators thus have a unique opportunity to clarify lineage-specific influenza b responses in a well-characterized cohort of children originally primed to yamagata. the investigators' main interest is to assess whether titre i children primed with two doses of b/yamagata in 2008-09 have since or are now capable of achieving a sufficient antibody response to b/victoria following a single dose of 2018-19 qiv, ten years after their initial tiv b/yamagata priming exposure.


Eligibility criteria:
inclusion criteria: * child previously completed the titre i study in british columbia or quebec; * child is healthy (stable chronic conditions acceptable) as established by health assessment interview and verbal history-directed health examination; * child is available and can complete all relevant procedures during the study period; * parent or legal guardian is available and can be reached by phone during the study period; * parent/guardian provides written informed consent; * parent/guardian is fluent in english/french exclusion criteria: * child has already received the 2018-19 seasonal (tiv or qiv) influenza vaccine; * child has a bleeding condition that would prevent vaccine injection or blood collection; * child has known or suspected immunodeficiency; * child has a suspected or known anaphylactic reaction to any of the vaccine components used in this study; * child has a health condition which, in the opinion of the investigator, would interfere with the evaluation or pose a health risk to the child; * child has received immune globulin or other blood products within the prior six weeks; * child has received injected or oral steroids within the prior six weeks defined by more than 1 week of immunosuppressants or immune modifying drugs (e.g. oral prednisolone \>0.5ml/kg/day or intravenous glucocorticoid steroid). nasal, topical or inhaled steroids are allowed; * child has received any live vaccine within 28 days of the study vaccine or is scheduled to receive live vaccine during the study period; * child has received any inactivated vaccine within 14 days of the study vaccine; * child is or will be enrolled in any other clinical trial of a drug, vaccine or medical device during the study period.