Two SARS (severe acute respiratory syndrome) studies - one in the Journal of Infectious Diseases and one in Clinical Infectious Diseases â€“ raise the possibility that SARS may spread through the air and not only through direct person-to-person contact.

In the first study, conducted in Toronto, Canada during an outbreak in 2003, researchers collected air samples from the SARS units of four hospitals. They detected the SARS coronavirus in the air of one patientâ€™s room, the first confirmation of the virus in an infected personâ€™s room.

The second study, from Hong Kong, found that 50 percent of patients in hospital bays adjacent to a SARS patient became infected, compared with 18 percent of patients in hospital bays further away.

Neither study revealed a documented case of airborne transmission of SARS, but the higher rates of infection among nearby patients in the Hong Kong study suggest it is possible.