(January 16, 2004) -- In its first assessment of the effectiveness of this year's flu shot, the Centers for Disease Control found it had no or very low effectiveness -- in the range of 3%-14% -- against the virulent Fujian strain of flu now widespread in CA and against influenza like illness...but said it "probably provides" some immunity and reduces the severity of the disease.

The agency cautioned that the poor results of this year's flu shot in preventing the Fujian flu don't indicate the flu shot's effectiveness against more severe illness outcomes or against influenza B or influenza A (both currently less prevalent) or the effectiveness of the live attenuated flu vaccine.

In a related development, CDC said in its Jan. 16 update on flu activity, "Although vaccine effectiveness against A/Fujian/411/2002-like viruses might be less than that against A/Panama/2007/99-like viruses, the current U.S. vaccine probably offers some cross-protective immunity against the A/Fujian/411/2002-like viruses and reduces the severity of disease." The update indicated flu was reported as widespread in CA during the Jan 4-10 reporting period.

CDC added in its January 16 Morbidity and Mortality Weekly Report, "Despite a suboptimal antigenic match, TIV [the injectable flu vaccine, "trivalent inactivated influenza vaccine"] can still provide protection against influenza complications. In a study conducted among patients aged > 65 years, TIV was effective in preventing 61% of influenza-related deaths when the vaccine and circulating strains were well matched and 35% when they were not well matched.

CDC acknowledges that "The predominant influenza viruses (A/Fujian/411/2002 [H3N2]-like viruses) circulating this season differ antigenically from the 2003--04 influenza A (H3N2) vaccine strain [footnote omitted]."

In its first assessment of the effectiveness of this year's flu shot, CDC says Children's Hospital in Denver provided employee flu shots...and then surveyed workers on whether they got the flu or influenza like illness (ILI). "Point estimates for vaccine effectiveness were 14% and 3%, respectively," CDC said. The agency added: