Large trial finds 55% efficacy for 4-strain flu vaccine in kids

A study billed as the first large, randomized clinical trial of a quadrivalent (four-strain) influenza vaccine showed that GlaxoSmithKline’s FluLaval Quadrivalent was about 55% efficacious in protecting children ages 3 to 8, similar to some previous findings for trivalent vaccines, according to a report published in the New England Journal of Medicine. The trial also suggested that the vaccine was somewhat better at protecting children against “moderate to severe” flu, with an efficacy of more than 70% for such cases. But because of flu circulation patterns during the trial, it couldn’t answer a key question about quadrivalent vaccines: whether they achieve the intended goal of improving protection against influenza B, compared with trivalent vaccines. Unlike trivalent vaccines, quadrivalent vaccines contain two influenza B strains, with the aim of improving protection by targeting both of the common B lineages. In recent years it has been difficult to predict which lineage, Victoria or Yamagata,...