While the flu season continues to show signs that it has peaked, it is hitting those over 65 the hardest, sending record numbers of older Americans to hospital, U.S. health officials reported.
Seniors may be hit harder by influenza this year because the predominant strain, H3N2, tends to be especially harmful in that age group, said Dr. Michael Jhung, a medical officer the Influenza Division at the U.S. Centres for Disease Control and Prevention.
Vaccine not well matched
According to Jhung, another reason for the record number of elderly hospitalisations may be that this year's vaccine is not well matched to this year's flu strains.
"We are seeing more serious illness in elderly folks this year, even more so than in 2012-2013," he said.
"That happens every time we have an H3N2 year, and this year happens to be the worst we've seen."
183 cases per 100,000
At the end of the 2012-2013 season, the rate of flu-linked hospitalisations for people 65 and older was around 183 cases per 100,000, according to Jhung.
But this season, "we have [a rate of] 217 per 100,000," he noted, "and we have several weeks of the flu season to go, so that number is going to go up."
Compounding matters, this year's vaccine is only 23 percent effective overall and only 14 percent effective in people 50 and older, Jhung said.
"That combination of things is responsible for this high number of hospitalizations," he said.
Read: Cold or flu?
Typically, flu is more common among the unvaccinated. But this year there's been a lot of flu both in people who are vaccinated and those who aren't, CDC officials said.
However, even a 23 percent vaccine effectiveness rate means many people will still gain some benefit from a flu shot, the CDC said.
But the elderly are at a slight disadvantage, the CDC said. That's because the effectiveness of the flu vaccine is often tied to the health of the recipient: Flu shots usually work best in young, healthy people, and are less effective in those 65 and older.
On the bright side, Jhung said the U.S. flu season has peaked, and although several more weeks of flu activity are expected, the season appears to continue to wind down.
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By 7 February, all areas of the country reported flu activity at or above baseline levels, the CDC reported.
Fifteen states and Puerto Rico experienced high activity. However, some areas were getting some relief: By the beginning of February, 12 states – Alaska, Florida, Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Montana, Ohio, Oregon and Wisconsin – reported "minimal" flu activity, the CDC said.
This year's flu season has also hit children hard, the agency said, with 80 children dying from complications of flu by 7 February. For context, the CDC notes that in an average year, child deaths from flu vary from as few as 30 to as many as 170 or more.
Vaccination can still prevent some infections
The CDC currently recommends that everyone 6 months and older get vaccinated. Even if the flu shot isn't a perfect match to circulating strains, vaccination can still prevent some infections and reduce severe disease that can lead to hospitalisation and death, the agency said.
Other ways to treat and prevent flu from spreading include early treatment with antiviral drugs such as Tamiflu and Relenza, and washing hands frequently and covering your mouth when coughing or sneezing.
Read: Flu vaccine missing its mark
Early treatment with antiviral drugs is especially important for children 2 years and under and adults 65 and older, Jhung said.
Others for whom these drugs are essential are people with diabetes, heart disease or breathing problems, he said.
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