Flu Season Was One of Mildest on Record, CDC Confirms

Fewer deaths, hospitalizations this year than in the past, agency says

Thursday, June 7, 2012

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THURSDAY, June 7 (HealthDay News) -- This past flu season started later than most and was one of the mildest on record, health officials reported Thursday.
Compared with recent flu seasons, this one saw fewer people going to their doctor with flu symptoms, along with fewer hospitalizations and deaths from flu, according to the U.S. Centers for Disease Control and Prevention.
Dr. Joseph Bresee, chief of the epidemiology and prevention branch in the CDC's influenza division, said there are several factors that might explain the mild flu season.
"The viruses that circulated this year were similar to the viruses that circulated last year," he said. "So, there are probably a lot of people in the United States [who were] exposed to these viruses before, so the level of immunity of the population was probably fairly high going into the year."
In addition, there were lots of vaccines used in the last couple of years and the vaccines haven't changed, which is unusual for flu, so a lot of people have been vaccinated, Bresee said.
It was also a very mild winter, which appears to slow the spread of flu, he said.
But next flu season could be entirely different, Bresee cautioned.
"Flu viruses change. We never know whether it's going to be severe or mild. The fact that we had a mild flu season this year doesn't mean that next year you will see a mild season as well," he explained.
"Flu is unpredictable, it's serious, and you ought to get vaccinated against the flu that comes around next year," Bresee added.
The report was published in the June 8 issue of the CDC's Morbidity and Mortality Weekly Report.
The number of children who died from flu was the lowest since the CDC started collecting data on this in the 2004-2005 season. This season, 26 children died from the complications of flu.
During the 2010-2011 season, 122 children died. During the 2009 pandemic a total of 348 children died, and there were 67 deaths during the 2008-2009 season.
The most common flu virus this season was influenza A (H3N2). But, influenza A (H1N1), the pandemic virus from 2009, and influenza B viruses also circulated widely.
Most of these virus strains were similar to those included in this year's vaccine. In addition, antiviral drugs were effective against these strains, the CDC researchers noted.
The CDC urges everyone to get an annual flu shot because it is the most effective way of preventing flu. Vaccination is recommended for almost everyone aged 6 months or older.

SOURCES: Joseph Bresee, M.D., chief, epidemiology and prevention branch, influenza division, U.S. Centers for Disease Control and Prevention; June 8, 2012, Morbidity and Mortality Weekly Report

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