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Published on: December 1, 2017
Safety and immunogenicity of trivalent inactivated influenza vaccine in infants: a randomized double-blind
Janet A Englund1, Emmanuel Walter, Steven Black
1Department of Pediatrics, Division of Infectious Diseases, Children's Hospital Research Institute, University of Washington, Seattle, WA, USA. Janet.Englund@seattlechildrens.org
Insights
This study found that trivalent inactivated influenza vaccine (TIV) is safe and effective in infants 6 to 12 weeks old. Vaccinating young infants with TIV provides crucial protection against influenza disease.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Infants under 6 months are highly susceptible to influenza and its complications.
- Currently, no influenza vaccine is licensed for infants younger than 6 months.
- This age group faces significant risk for severe influenza outcomes.
Purpose of the Study:
- To evaluate the safety and immunogenicity of trivalent inactivated influenza vaccine (TIV) in infants aged 6 to 12 weeks.
- To determine the antibody responses and adverse events following TIV administration in this vulnerable population.
Main Methods:
- A double-blind, randomized, placebo-controlled trial involving 1375 healthy US infants (6-12 weeks old).
- Participants received two doses of TIV (N=915) or placebo (N=460) one month apart, alongside routine childhood vaccines.
- Safety was monitored via solicited adverse events (7 days) and unsolicited adverse events (28 days); immunogenicity was assessed by hemagglutination-inhibition antibody titers.
Main Results:
- TIV demonstrated a comparable safety profile to placebo, with no significant differences in adverse events.
- Fever occurred in 11.2% of TIV recipients versus 11.7% of placebo recipients.
- TIV recipients showed significantly higher antibody responses against all three influenza strains compared to placebo recipients (P < 0.001).
- Over 90% of TIV recipients achieved protective antibody levels (≥1:40) for at least one strain.
Conclusions:
- Trivalent inactivated influenza vaccine (TIV) is safe for administration to infants as young as 6 to 12 weeks of age.
- TIV is immunogenic in this age group, eliciting protective antibody responses against influenza.
- Early influenza vaccination in infants offers a promising strategy for disease prevention.
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.
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