Swine flu not as catchy as other pandemic strains

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Swine flu not as catchy as other pandemic strains

By MARILYNN MARCHIONE AP Medical Writer

How contagious is swine flu? Less than the novel viruses that have caused big

world outbreaks in the past, new research suggests.

If someone in your home has swine flu, your odds of catching it are about one in

eight, although children are twice as susceptible as adults, the study found. It

is one of the first big scientific attempts to find out how much the illness

spreads in homes versus at work or school, and who is most at risk.

The study was done by outbreak specialists from Imperial College London and from

the U.S. Centers for Disease Control and Prevention. Results are in Thursday's

New England Journal of Medicine.

Swine flu has sickened an estimated one-sixth of Americans since the novel virus

was first identified in April. The second wave of cases now seems to have

peaked, and health experts do not know if another surge lies ahead.

People with swine flu are advised to stay home for at least a day after their

fever goes away by itself to avoid spreading illness. That puts family members

at risk, but who is vulnerable and to what extent has not been known.

About 60 percent of swine flu cases have been in children, but researchers

wondered: are they truly more likely to get swine flu, or just more likely to be

taken to a doctor and tested for it? Are they more likely to spread the virus

than adults are?

To find out, researchers studied infection patterns in 216 people with swine flu

from around the United States (half of them children) and 600 people living with

them.

Respiratory illnesses that researchers assumed were swine flu developed in 78 of

the 600 household members, or 13 percent. However, 10 percent had symptoms more

specific to flu.

That's less than the " spread " rate during earlier flu pandemics in 1957 and

1968, when 14 percent to 20 percent of household members were infected. Less is

known about spread in the 1918 pandemic, but households and lifestyles were very

different then. In an ordinary flu season, the virus spreads to 5 percent to 40

percent of household members, various studies have shown.

Children were twice as susceptible to catching swine flu as adults were, and

even more so if they were younger than 4, said one of the researchers, Lyn

Finelli, surveillance chief for the CDC's flu division.

" It fits with what I'm seeing clinically, " said Dr. King, chairman of the

American Academy of Family Physicians' board of directors and a family medicine

doctor in Selmer in western Tennessee. " Most of the people I'm seeing are people

under 20, mostly kids, " he said.

Nearly three-fourths of households in the study managed to avoid spreading the

illness to any family members.

In homes where the germ was transmitted, researchers found something unexpected:

" People at all ages were just as likely to spread the virus, " Finelli said.

" That was surprising, since we always think of kids as super-spreaders. "

The study was funded by several public and private health-related groups in

England and the United States, including the Bill & Melinda Gates Foundation.

http://www.miamiherald.com/living/health/healthAP/story/1403618.html