Flu vaccine proving ineffective against US strain

The 2003-2004 influenza vaccine seems to offer little protection against the strain that has dominated this year’s flu season in the U.S., according to a report released Thursday by the Centers for Disease Control and Prevention.

The 2003-2004 influenza vaccine seems to offer little protection against the strain that has dominated this year’s flu season in the U.S., according to a report released Thursday by the Centers for Disease Control and Prevention. The report, which is based on a survey of healthcare workers at a children’s hospital in Colorado, indicates that no more than 14 percent of people who received the vaccine were actually protected against this strain. The findings appear in the CDC’s Morbidity and Mortality Weekly Report. The flu virus most people are catching this year is called the Fujian strain. The vaccine’s poor protection is not a complete surprise to the CDC given that the vaccine was not formulated against Fujian, but rather against a closely related strain called Panama. Still, because of study limitations, the current findings should only be considered an estimate of the vaccine’s effectiveness, the CDC emphasizes. Although the survey was given to about 3100 workers, only 1886 (61 percent) responded, the Atlanta-based agency notes. Moreover, because influenza cases were based on self-reports, not lab tests, it was impossible to know for certain if the subjects actually had influenza. “Further studies are under way or planned to estimate the effectiveness of the 2003-04 influenza vaccine against laboratory-confirmed influenza and influenza-related complications,” the report indicates. Despite the current findings, the CDC maintains that this year’s vaccine is still useful in protecting against influenza complications. In a recent study of older adults, immunization with an influenza vaccine, even if it was poorly matched against the main strain, could prevent at least 35 percent of influenza-related deaths. (Source: orbidity and Mortality Weekly Report,Reuters Health, Jan, 2004)