Inactivated Influenza Vaccine Clinical Trial
Official title:
Safety and Immunogenicity of Fluzone Influenza Virus Vaccine (2005-2006 Formulation) Among Healthy Children 6 to 12 Weeks of Age
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.
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.
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Allocation: Randomized, Endpoint Classification: Safety Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention