For the average American without any underlying high risk medical condition, the chances of being hospitalized for H1N1 infection is almost zero.

A preliminary CDC analysis has confirmed that most patients hospitalized with the pandemic H1N1 influenza virus had underlying conditions that increased their risk for complications.

CDC has reported that 70 percent of people who have been hospitalized with the 2009 H1N1 virus have had one or more medical conditions previously recognized as placing them at “high risk” of serious seasonal flu-related complications. That is to say, these individuals were likely to be hospitalized from flu related illness regardless of the strain of flu involved.

In more than 500 hospitalized children evaluated, the most common conditions included asthma, chronic lung disease, neurologic and neuromuscular disorders, and sickle-cell anemia and other blood disorders, Anne Schuchat, MD, of the CDC's National Center for Immunization and Respiratory Diseases, said on a conference call with reporters.

Among about 1,400 hospitalized adults, the most common conditions were asthma, diabetes, chronic lung disease, chronic heart disease, and immunosuppression.

One fact reported by CDC that has not received wide media coverage is that the total number of laboratory confirmed deaths in children from H1N1 in the U.S. during the six month period April through September is relatively low at 76.

Of the 76 children that died in the six month period documented, 70 percent of these children also had Staphylococcus aureus or “Staph” infections with nearly half of those typed as Methicillin Resistant Staphylococcus Aureus (MRSA).

Other bacterial infections present in the 76 children that died included: Streptococcus constellatus, Pseudomonas aeruginosa, Streptococcus, and Enterococcus.

To put this number of deaths into proper perspective, in 2006 there were 756 pediatric homicides. In that same year, without any “pandemic”, there were 436 pediatric deaths caused by influenza and pneumonia.*

The findings came from a preliminary look at data covering hospitalizations from the beginning of the outbreak in April through the end of August.

Schuchat said the agency has continued to monitor hospitalizations to make sure there were no risk factors for complications that were overlooked.

The information was reported to the CDC's Emerging Infections Program, which receives data from 10 state health departments and their local collaborators.

In addition to the underlying chronic medical conditions, pregnancy remained notable among the hospitalized adults; 6.1% were pregnant.

Schuchat said pregnancy increases the risk of flu-related complications because a mother's immune system is suppressed so the body does not have a reaction to the fetus, increasing vulnerability to all infections. In addition, she said, as the baby grows, the mother's airways can become restricted, making it harder to fight off a lung infection.