It's because the old folks are less likely to catch it.
"People 65 Years and Older and 2009 H1N1 Flu
The new 2009 H1N1 virus does not seem to be affecting people 65 years and older in the same way that seasonal flu usually does. Most people who have gotten sick from this new virus have been younger. In fact, people 65 and older are the group that is least likely to get infected with this new virus. There have been relatively few infections and even fewer cases of serious illness and death with this new virus in people older than 65. Laboratory tests on blood samples indicate that older people likely have some pre-existing immunity to the 2009 H1N1 flu virus. But while people 65 and older are the least likely to be infected with 2009 H1N1 flu, those that do become infected are at greater risk of having serious complications from their illness."
http://www.cdc.gov/h1n1flu/65andolder.htm