Safety and Immunogenicity of Inactivated Influenza Virus Vaccine Among Healthy Children 6-12 Weeks of Age
Condition: Inactivated Influenza Vaccine
MeSH terms: Influenza, Human
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      Study of the safety and immunogenicity (antibody producing capability) comparing inactivated
      influenza vaccine to placebo given to infants at 2 and 3 months of age. Infants will receive
      inactivated influenza vaccine at the same time as other vaccines on the routine immunization
      schedule. Infants will be randomized at enrollment to receive inactivated influenza vaccine
      or placebo at a 2:1 ratio. This study is double-blind, randomized, and placebo-controlled.
    

Detailed description: 
      Methods: A double-blind, randomized, placebo-controlled trial was conducted in 1375 healthy
      US infants 6-12 weeks of age. Subjects received either 2 doses of trivalent inactivated
      influenza vaccine (TIV, Fluzone®, sanofi pasteur 2005-6 pediatric formulation) (N=915) or
      placebo (N=460) 1 month apart, along with indicated concomitant vaccines. Solicited adverse
      events were collected for 7 days following each vaccination, unsolicited adverse events for
      28 days, and serious adverse events for 6 months. Hemagglutination inhibition antibodies to
      all 3 vaccine strains were measured following the second TIV/placebo dose.

      Results: No significant differences were seen between TIV and placebo groups for any safety
      outcomes. Fever ≥38oC rectal within 3 days of vaccination was seen in 11.2% vs 11.7% of TIV
      vs placebo recipients. Serious adverse events within 28 days of vaccine/placebo were reported
      in 1.9% of TIV and 1.5% of placebo recipients; only one (hypersensitivity reaction in a TIV
      recipient) was considered vaccine-related. Significantly increased antibody responses
      (p<0.001) were seen against all 3 strains in TIV recipients by titer ≥ 1:40 or geometric mean
      titer (GMT) (p<0.001). Altogether, 50% of infants had antibody titers ≥ 1:40 for H1N1, 86%
      for H3N2, and 11% for B compared with 7%, 10%, and 0.3% in the placebo group. The reciprocal
      GMT for influenza recipients was 33, 95, and 11 for H1N1, H3N2, and B vs. 7, 9, and 5 for
      placebo recipients. Over 90% of infants who received TIV had antibody ≥ 1:40 for at least one
      vaccine strain and 49.6% for 2 strains, vs. 16.4% and 0.9% in the placebo group.

      Conclusions: TIV administered to young infants beginning at 6-12 weeks of age is safe and
      immunogenic.
    

Intervention name(s): 2005-2006 trivalent inactivated influenza vaccine
Intervention type(s): Biological
Intervention description(s): Children enrolled at 6-12 weeks to receive first dose, 0.25 ml of trivalent inactivated influenza vaccine, 2005-6 pediatric Fluzone formulation (sanofi pastuer), with concomitant routine pediatric vaccines. Second dose administered 4 weeks later.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: influenza vaccine; infants; safety; immunogenicity