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Quadrivalent flu vaccines show good immunogenicity against added B strain
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Phase 3 clinical trial data of GlaxoSmithKline’s quadrivalent influenza vaccine are showing “superior immunogenicity for the additional B strain” over the trivalent influenza vaccine, according to results published online.
Joseph B. Domachowske, MD, of Upstate Medical University, and colleagues reported results of a trial in which 2,738 children aged 3 to 17 years from the United States, Czech Republic, France, Germany and the Philippines were randomly assigned to receive one of the two vaccines.
Joseph B. Domachowske
“[Quadrivalent influenza vaccine, (QIV)] was highly immunogenic; seroconversion rates were 91.4%, 72.3%, 70.0%, and 72.5% against A/H1N1, A/H3N2, B/Victoria, and B/Yamagata, respectively,” the researchers concluded. “Reactogenicity and safety of QIV was consistent with TIV.”
Domachowske and colleagues noted two potential limitations to the study, specifically that natural exposure to influenza could have been a confounding factor, and that the immunogenicity data provided no information on the magnitude of protection against influenza B illness.
“QIVs contain an added B-lineage strain not included in TIVs,” Domachowske told Infectious Diseases in Children. “Our multicenter, phase 3 pediatric clinical vaccine trial demonstrated safety and immunogenicity of a new inactivated QIV that was similar to both comparator trivalent vaccines, with enhanced antibody responses to the added B strain. The availability of safe and immunogenic QIV vaccines offers a new strategy to broaden protection of children against influenza infection.”
The researchers said their findings indicate that QIV provides a good alternative to TIV, particularly in years of B strain “mismatch.”
Joseph B. Domachowske, MD, can be reached at Upstate Medical University, Department of Pediatrics, 750 E. Adams St., Syracuse, NY 13210; phone: 315-464-7577; email: domachoj@upstate.edu.
Disclosure: All participating institutions received compensation from GlaxoSmithKline for study involvement.
Perspective
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Henry H. Bernstein, DO
This study by Domachowske and colleagues compared the immunogenicity and reactogenicity of an inactivated QIV with that of two inactivated TIVs in healthy children aged 3 to 17 years. Besides the shared influenza A strains, the QIV formulation contained antigens from both B lineages, whereas each TIV formulation contained antigen from only a single influenza B lineage.
QIV compared favorably with TIV against the shared influenza A and B strains. In addition, superiority against alternate-lineage B strains was demonstrated for QIV vs. TIV. Therefore, the authors concluded that QIV provides protection against an additional B strain without interfering with immune responses to the other seasonal vaccine strains.
The authors also found that the reactogenicity and safety of QIV was consistent with the established profile of TIVs in this age group. The additional 15 mcg of influenza B antigen found in QIV did not lead to significant additional adverse events.
This study suggests that vaccinating children aged 3 to 17 years with QIV rather than TIV may provide better protection from influenza-associated morbidity and mortality. QIV produced immune responses against the two antigenically distinct lineages of influenza B viruses without compromising the immune responses to the other seasonal vaccine strains. No unusual safety concerns were noted with the addition of the second B strain.
Immunizing against B virus strains of only one lineage provides limited cross-protection against strains in the other lineage. In addition, it has proved difficult to predict which of the two B virus lineages will circulate during any given season. Therefore, inclusion of two B virus strains (one from each lineage) in seasonal influenza vaccines may provide better overall protection against circulating seasonal B strains.
Although the effectiveness of seasonal influenza has room for improvement, it is the best available tool we have for preventing influenza illness. Several new and recently FDA approved quadrivalent vaccines will be available for the 2013-2014 season. These should be acceptable alternatives to other approved vaccines indicated for the specific age group when otherwise appropriate.
Research also continues on how to improve upon our current influenza vaccine formulations. Utilizing a quadrivalent rather than a trivalent influenza vaccine remains a very promising strategy to better maximize overall vaccine effectiveness.
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