- 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 bowmanl@shns.com.
|
