This season’s flu vaccine has been 59% effective against the flu, comparable to past seasons with a well-matched vaccine, according to preliminary data released this week by the Centers for Disease Control and Prevention. The vaccine’s effectiveness varies with the strain of the virus, ranging from 51% effective against the predominant H1N1 strain to 76% or more for two other strains examined. Joseph Bresee, M.D., chief of CDC’s Epidemiology and Prevention Branch, said the finding “underscores the importance and the benefit of both annual and ongoing vaccination efforts this season." CDC this month recommended rapid antiviral use for all hospitalized patients with suspected flu, citing reports of severe respiratory illness or death in young- to middle-aged adults infected with the H1N1 strain. The agency also recommends prompt antiviral therapy for high-risk outpatients and those with progressive disease, even if flu has not been confirmed by laboratory testing. Flu activity “is still on the upswing and expected to continue for several weeks,” Bresee said.