Data from Texas households confirm that the virus tends to target children
WEDNESDAY, March 10 (HealthDay News) -- The H1N1 swine flu appears to spread more slowly than "regular" seasonal flu in a household setting, but when it does spread it's more likely to affect children, a new study suggests.
"We found that about 9 percent of people who lived with a household member with [H1N1] flu also got flu," said lead researcher Oliver Morgan, an Epidemic Intelligence Service officer with the U.S. Centers for Disease Control and Prevention.
"We found that 18 percent of children under 5, and 11 percent of children 5 to 18, got flu in the household," Morgan said, adding that children were more likely to introduce flu into the household.
The findings are published in the April issue of the CDC journal Emerging Infectious Diseases.
For the study, Morgan's team began looking at the H1N1 outbreak when it first started in the United States in April and May of 2009. The researchers examined more than 3,400 flu samples from the San Antonio, Texas, area, one of the first sites to experience infections.
The researchers were able to identify 97 cases of pandemic H1N1 flu in 77 households. In about 30 percent of the homes, additional family members became sick within four days of a child coming down with the flu.
The so-called attack rate of the H1N1 flu -- how fast it spreads -- was 4 percent, which is lower than that seen with seasonal flu and lower than what would be expected for a pandemic flu, the researchers said.
Most of the flu and the highest attack rates were seen among children, reinforcing earlier findings that the H1N1 swine flu tends to target children and younger adults.
Morgan said the study was done at the start of the epidemic in the United States to learn more about the H1N1 virus, about which relatively little was known at the time. "This gave us an idea
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