H1N1 Predominant Flu Strain This Year
(HealthDay News) — The H1N1 flu was the predominant influenza strain in the United States this year, but it packed a lot less punch than in 2009 when it caused a worldwide pandemic, health officials report.
As the 2013–14 flu season winds down, the US Centers for Disease Control and Prevention is able to make some comparisons with previous flu seasons, although final figures aren't yet available. As in 2009, H1N1 hit younger adults harder than the elderly. Of the more than 8,000 influenza-associated hospitalizations reported so far this season, over 60% have been among people 18–64 years old, the CDC said.
The CDC relies on hospital data to estimate adult deaths at the end of the flu season, and it's too soon to obtain those figures, Michael Jhung, MD, MPH, a medical officer in the CDC's influenza division, told HealthDay. Adult flu deaths in the United States usually range from 35,000–40,000 a year. The agency does have up-to-date records for children, however. So far this season, 85 children have died from flu. By the end of March last year, 110 children had died of flu. Five states – Arkansas, Louisiana, New Mexico, Oklahoma, and Texas – accounted for 29 of this season's pediatric deaths, according to the CDC.
"This year, not only do we have a vaccine that works well, but millions of people have already been exposed to the H1N1 virus," Jhung told HealthDay. Although H1N1 flu has circulated since 2009, "this is the first season since then we have seen it dominate," he added. The timing was different, too. "We had a bit of an early peak to the flu season," Jhung said. "We typically see the highest activity in January/February, but it happened this season about a month early." This year's flu vaccine protected people from H1N1 and other flu types, including H3N2 and a type of influenza B virus. Some formulations of the vaccine had an additional B strain, protecting people against four types of flu, Jhung said.