Severe Swine Flu Can Kill Young, Old Alike

Nov. 4 -- TUESDAY, Nov. 3 (HealthDay News) -- Californians both young and old are contracting H1N1, with infants the most likely to be hospitalized and adults over the age of 50, once hospitalized, the most likely to die, a new study shows.

The report, appearing in the Nov. 4 issue of the Journal of the American Medical Association, somewhat contradicts the popularly held notion that elderly people are relatively immune from the ravages of this new infection.

Even though the numbers of elderly hospitalized and dying are relatively small, "that small proportion that are hospitalized who are elderly should be watched because they are at a higher risk of having a bad outcome once hospitalized. It doesn't mean they have a higher risk of infection," said study author Dr. Janice Louie, a public health medical officer with the California Department of Health.

One top federal expert agreed.

"This is quite consistent with data we've seen from this country, as well as globally, and it does emphasize that providers should think of H1N1 in all age groups," Dr. Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention, said during a Tuesday teleconference. "It doesn't change what the recommendations would be for vaccination because H1N1 is overwhelmingly affecting those under the age of 65."

The first U.S. cases of H1N1 appeared in California on April 17, 2009, then spread rapidly.

Data so far indicates that infection with H1N1 results in relatively mild illness and that most people who become ill are younger: 40 percent are aged 10 to 18, and 95 percent are under the age of 50. Experts have long thought that many older Americans may have some level of immunity to H1N1, because of exposures to prior outbreaks decades ago.

In the study, the team looked at the first 1,088 H1N1 cases in California that involved hospitalization or death between April 23 and Aug. 11, 2009.

The median age of patients was 27, and about a third were children under the age of 18, the researchers reported.