Larry M. Baddour, MD

An inactivated quadrivalent vaccine, containing both B lineages, was efficacious in a multinational trial.

Children are at increased risk for influenza and its complications, so including them in vaccine trials is critical. Researchers have now conducted a manufacturer-funded, multinational, phase III, observer-blinded trial of a novel inactivated quadrivalent influenza vaccine (QIV) in children aged 3 to 8 years.

About 5200 children were randomly assigned to receive either the QIV vaccine (which contains both B lineages to prevent B-lineage mismatch) or hepatitis A vaccine as a control. The primary endpoint was influenza A or B confirmed by polymerase chain reaction (PCR) assay; secondary endpoints included moderate-to-severe PCR-confirmed influenza and culture-confirmed influenza, caused by seasonal strains that antigenically matched the vaccine or by any seasonal strain.

In the total vaccinated cohort, the QIV's efficacy was 59.3% for PCR-confirmed influenza of any severity, 59.1% for culture-confirmed influenza, and 74.2% for moderate-to-severe PCR-confirmed influenza. In the per-protocol cohort (about 4800 patients), the QIV's efficacy was 55.4%, 55.9%, and 73.1%, respectively, for the same categories and was highest against moderate-to-severe influenza A. The QIV was immunogenic against all four vaccine strains. Injection-site pain was more common in the QIV group than the control group (47.7% vs. 34.8%), as were serious adverse events (1.4% vs. 0.9%).

Citation(s):

Jain VK et al. Vaccine for prevention of mild and moderate-to-severe influenza in children. N Engl J Med 2013 Dec 11; [e-pub ahead of print].