Safety and immunogenicity of trivalent inactivated influenza vaccine in infants: a randomized double-blind placebo-controlled study.
BACKGROUND
Infants less than 6 months of age are at high risk for influenza disease and influenza-related complications, but no vaccine is licensed for this population.


METHODS
A double-blind, randomized, placebo-controlled trial was conducted in 1375 healthy US infants 6 to 12 weeks of age. Subjects received 2 doses of trivalent inactivated influenza vaccine (TIV, Fluzone, sanofi pasteur; N = 915) or placebo (N = 460) 1 month apart in combination with indicated concomitant vaccines. Solicited adverse events were collected for 7 days following vaccination, and unsolicited adverse events for 28 days. 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 outcome. Fever > or =38 degrees C within 3 days of vaccination was seen in 11.2% versus 11.7% of TIV versus placebo recipients. Serious adverse events within 28 days were reported in 1.9% of TIV and 1.5% of placebo recipients. Antibody responses to childhood vaccines were similar in both groups. Increased influenza-specific antibody responses in TIV recipients compared with placebo recipients were seen against all 3 strains in TIV recipients (P < 0.001), with better responses to influenza A strains noted. Reciprocal geometrical mean titer to H1N1, H3N2, and B were 33, 95, and 11 in TIV recipients versus 7, 9, and 5 for placebo recipients. Over 90% of TIV recipients had antibody > or =1:40 for at least 1 vaccine strain and 49.6% for 2 strains, versus 16.4% and 0.9% in placebo-recipients.


CONCLUSIONS
TIV administered to young infants beginning at 6 to 12 weeks of age is safe and immunogenic.
Englund
Janet A
JA
Department of Pediatrics, Division of Infectious Diseases, Children's Hospital Research Institute, University of Washington, Seattle, WA, USA. Janet.Englund@seattlechildrens.org
Walter
Emmanuel
E
Black
Steven
S
Blatter
Mark
M
Nyberg
Jack
J
Ruben
Frederick L
FL
Decker
Michael D
MD
D000914:Antibodies, Viral / Q000097:blood; D004311:Double-Blind Method; D064420:Drug-Related Side Effects and Adverse Reactions; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D007223:Infant; D007252:Influenza Vaccines / Q000009:adverse effects* / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D010919:Placebos / Q000008:administration & dosage; D014481:United States; D014611:Vaccination / Q000379:methods; D015164:Vaccines, Inactivated / Q000009:adverse effects / Q000276:immunology
D000914:Antibodies, Viral; D007252:Influenza Vaccines; D010919:Placebos; D015164:Vaccines, Inactivated