The influenza vaccine that many Americans clamored for this year was not very good at protecting people against influenza, colds and similar viruses, a preliminary report published Thursday shows.
The study is the first attempt to show whether the vaccine that many sought after a flu scare this autumn and winter actually worked.
The study of hospital workers in Colorado, a state that was hit early and hard by influenza, showed the vaccine had “no or low effectiveness against influenza-like illness,” the U.S. Centers for Disease Control and Prevention said in its report.
Same rate of illness
Many experts did not expect the vaccine to work well, although the CDC had hoped it would at least prevent some of the worst illnesses caused by this year’s strain of influenza.
The vaccine is only meant to protect against true influenza. Without a test, it is often difficult to distinguish between influenza and other, similar viruses.
CDC spokesman Tom Skinner said that for this reason the report only shows part of the story.
“This is the first of a number of studies that we are going to do to try to answer the question, ’did this years’s vaccine offer protection against flu?’ This study in and of itself does not answer this question,” he said in a telephone interview.
However, the study shows that people who were vaccinated against influenza came down with colds, flu and similar viruses at the same rate as people who were not vaccinated. This would presumably include true influenza.
The vaccine is formulated each year in February or March, at the end of the northern hemisphere’s flu season, and did not include the Fujian strain of influenza, a new, mutated strain that turned out to be the predominant type of flu in the United States and several other countries this year.
The epidemic appears to be on the wane -- this past week only 2.8 percent of hospital visits were for influenza-like illnesses, compared to 5.5 percent the week before.
News coverage of the early start to the flu season sent many people rushing to get vaccinated. There were shortages in some places and the U.S. government bought 625,000 doses of flu vaccine from makers Chiron and Aventis.
It also negotiated a discount price for states to buy up to 3 million unsold doses of Wyeth and MedImmune’s FluMist vaccine, which is given nasally.
Experts knew the vaccines did not include the Fujian strain, but they did contain the related Panama strain, which they hoped would provide at least some protection.
The study, done among hospital workers at the Children’s Hospital in Denver, suggests it did not.
Of the 1,000 people vaccinated before Nov. 1, 149 developed influenza-like illness, or just under 15 percent. Of the 402 people who were not vaccinated, 68 got a flu-like illness, or just under 17 percent.