SARS can be transmitted between individuals living or who have cared for a SARS patient. Transmission can also occur from direct contact with the respiratory secretions or the bodily fluids of a patient who has SARS, while H1N1, on the other hand, can be transmitted by casual means such as sitting next to a person who has H1N1. Symptoms of SARS are very much likely to be more severe, which can also lead to liver, heart, or respiratory failure.
While the symptoms of H1N1 range from just mild headaches to more severe nausea. SARS is most contagious by people who come in contact with patients in their second week of the infection. People infected with H1N1 are able to infect others right from one day before their symptoms develop. The incubation period for SARS is about 2 to 7 days, while the incubation period for H1N1 is around 1 to 4 days.