The infectious period is an important factor when considering the spread of an infectious agent. For SARS-CoV,  the efficiency of transmission to close contacts appears to be greatest from patients with overt clinical symptoms, which was usually during the second week following the onset of symptoms. 

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- Incubation Period
- Infectious Period
- Case Fatality Rates

Transmission Dynamics of the SARS Epidemic, 2002-2003

Anderson, R. M., Fraser, C., Ghani, A. C., Donnelly, C. A., Riley, S., Ferguson, N. M., Leung, G. M., Lam, T. H., & Hedley, A. J. (2004). Epidemiology, transmission dynamics and control of SARS: the 2002-2003 epidemic. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 359(1447), 1091–1105. https://doi.org/10.1098/rstb.2004.1490

Epidemiology, transmission dynamics and
control of SARS: the 2002-2003 epidemic

The incubation period, the amount of time between being infected and presenting one or more symptoms, had a range of an estimated 2 to 12 days, with an average of 4.6 days. The relatively long incubation period allowed the virus to be transmitted globally by asymptomatic air travelers without their knowing. 

Incubation Period of the SARS Epidemic, 2002-2003 

Infectious Period of the SARS Epidemic, 2002-2003 

Case fatality rates (CFR) are used to describe the proportion of those infected that died from the disease compared to the total number of those who acquired the infection. In the case of SARS-CoV, the global average case fatality rate was estimated to be 15% by the WHO. However, it was also estimated that the CFR for patients younger than 60 years of age was 6.8%, while the CFR for patients older than 60 years was 55%. This shows that there is much variation in the mortality rate between age groups. 

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