Nishiyama, A., Wakasugi, N., Kirikae, T., et al. (2008). Risk Factors for SARS Infection Within Hospitals in Hanoi, Vietnam. Japanese Journal of Infectious Diseases. 61(5):388-90.
The authors looked at risk factors for nosocomial SARS infections in Vietnam in 2003. Consistent mask use by health care workers was found to reduce transmission of SARS among those exposed to patients with the disease.