Scientists at the CDC have noticed a new trend in cases of swine flu: "We were surprised by the frequency of obesity among the severe cases that we've been tracking," says an epidemiologist, adding that it might be cause to make obese people a priority for a vaccine, if it becomes available. Other pre-existing conditions, such as heart disease and diabetes, are known to raise the risk of flu complications, but this one has doctors a bit surprised.
Pregnancy can increase the severity of a case of flu because the woman's growing uterus pushes on her lungs, making it harder to breathe and cough. A similar thing could be happening in obese people. Two third of the H1N1 patients in California had some underlying condition that could have contributed to their flu: 11 out of 30 had lung problems.