Many of the deaths that have been announced after swine flu diagnoses have included the caveat that underlying health conditions have been a factor.

Many common conditions could actually contribute to a problem in fighting off the swine flu - or H1N1 - virus. These include asthma, heart disease, diabetes and possibly obesity. For asthma patients, this is not good news.

However, this doesn’t mean you are safe if you don’t have one of these conditions either. The World Health Organization is very concerned that H1N1 is causing deaths in otherwise healthy people - or at least, people who would have reported that they were healthy.

The tendency to report underlying conditions in conjunction with deaths is a kind of wishful thinking, according to Dr Michael Gardam. Gardam is the head of infectious disease prevention and control for Ontario’s public health agency. He says that we are clinging to the idea that people who die of swine flu were sick already, as a way of denying the danger.

With the seasonal flu, the main group that contracts a severe case are the elderly and very young. With H1N1, there is more severe disease in the adult population under 50. This pattern is much more similar to other lethal viral epidemics, such as the 1918 Spanish Flu pandemic.

Dr Allison McGeer is the influenza expert at Toronto’s Mount Sinai Hospital. She worries about labeling people. She says, “Half of me doesn’t want you to think you’re disease if you have asthma, and the other half of me wants you to get your flu vaccine.” The risk is real for asthmatics: 41 per cent of the hospitalized cases of swine flu in New York City had asthma.

Obesity is another real risk for those contracting swine flu. Early research from the US Centers for Disease Control show that it could be a factor in poor outcomes. Of the 700 hospitalized cases in New York, 4 patients were considered obese. It’s not clear whether it is a risk factor on its own, or if heart disease and diabetes are the real underlying problems.