The following are the common symptoms of having the H1N1 virus. If someone has these symptoms for seven days or more, it is advisable to see the doctor for early medication.
However, anyone with asthma or other respiratory illness, and perhaps even heavy smokers should be extra vigilant, because what makes severe cases of H1N1 more severe than regular flu is the way that it attacks the respiratory system. Seasonal flu is largely an upper respiratory illness, but in severe cases H1N1 moves deeper into the lungs and causes viral pneumonia. It is the complications from the pneumonia that has caused the vast majority of Swine Flu deaths.
Reference
H1N1 (swine) flu. (2011). In The Gale Encyclopedia of Medicine. Detroit: Gale. Retrieved from http://go.galegroup.com/ps/i.do?id=GALE%7CCV2642414058&v=2.1&u=uprcarolina&it=r&p=GPS&sw=w