The Verdict on This Year's
Flu Season - Late and Nasty
By Lee Bowman
Scripps Howard News Service
BETHESDA, Md. - The year's flu season came both unusually late and nasty, compounding the difficulty of predicting and forestalling the next wave of viruses.
Officials at the Centers for Disease Control and Prevention in Atlanta say the flu season didn't really get rolling until late January, probably peaked in late February - when major outbreaks were reported in nearly all states - and was still going strong last week, with death rates slightly ahead of what's normally expected.
At the end of February, flu-related deaths accounted for 8.1 percent of the total deaths reported in the U.S. for the final week of the month, the CDC said. It had expected a rate of 7.5 percent or less.
This pattern surprised many experts who had thought influenza would blow in strong before or during the Christmas holidays, based in part on unusual summer outbreaks in Alaska, Canada, and Florida last year.
Each year, influenza kills some 20,000 Americans and hospitalizes more than 100,000, mainly the elderly or people with immune systems compromised by other illness. It's estimated that between 25 million and 50 million get infected with one or more flu viruses each year.
Not only does a late season catch people off guard - and perhaps after their immunity from a fall shot has begun to fade - but it also makes it difficult for experts to choose what three strains should be included in the next batch of more than 80 million doses of vaccine Americans will start getting come October.
Nancy Cox, chief of the Influenza Branch at the CDC, said her team has only received the bulk of samples of several hundred strains from around the nation and world in the past month.
She told a federal advisory committee Thursday that no clear pattern of new types of flu had yet shown up.
Designing the vaccine is an educated guessing game against a foe that often defies prediction as it mutates and spreads around the globe. For instance, in 1997-98, an Australian variant, A-Sydney, arrived on the scene and sickened millions of people who had been immunized against the A-Wuhan virus that world and U.S. health experts had thought would be dominant.
It's almost doctrine that no flu strain will hold sway for more than a year or two, but the advisory committee to the Health and Human Services Department decided Thursday to stick with A-Sydney and another A strain, called Beijing 262-95, that was also updated last year.
Cox and Food and Drug Administration expert Roland Levandowski, said that while it appears some mutations of the Sydney strain have been cropping up, the majority of samples still appear likely to be moderately responsive to the vaccine.
"We're not changing the vaccine because we don't know what to change it to," said Dr. Robert Couch, an immunologist at Baylor College of Medicine in Houston and a member of the committee. The experts hastened to insist that they're confident the vaccine will still provide significant protection to people who get it next winter.
Despite their widespread use, particularly among the elderly and health care workers, relatively little research is done on how well flu shots really protect people. Cox pointed to one small California study involving 47 workers at a long-term care facility that showed the vaccine was about 72 percent effective - somewhat less than the 80-90 percent generally claimed for healthy people.
Lee Bowman covers health and science for Scripps Howard News Service. Bowman can be reached at