Donnelly CA, Ghani AC, Leung GM, et al. Epidemiological determinants of the spread of the causal agent of severe acute respiratory syndrome in Hong Kong. Lancet 2003;361: 1761–66— In this Article (May 24), the second and third sentences of the third paragraph of the Results section should have read: “The database contained 53 patients with one exposure to SARS over a limited time scale with recorded start and end dates. The maximum likelihood estimate of the mean and variance of the time from infection to onset was 3·81 days (95% CI 3·00–4·92) and 8·34 days,2 respectively; therefore 95% of patients were estimated to experience the onset of symptoms within 9·45 days of infection.” Panel A of figure 2 was also incorrect. The correct version appears below.