Abstract
The setting of a quarantine time for an emerging infectious disease will depend on current knowledge concerning incubation times. Methods for the analysis of information on incubation times are investigated with a particular focus on inference regarding a possible maximum incubation time, after which an exposed individual would be known to be disease free. Data from the Hong Kong SARS epidemic are used for illustration. The incorporation of interval‐censored data is considered and comparison is made with percentile estimation. Results suggest that a wide class of models for incubation times should be considered because the apparent informativeness of a likelihood depends on the choice and generalizability of a model. There will usually remain a probability of releasing from quarantine some infected individuals and the impact of early release will depend on the size of the epidemic. Copyright © 2005 John Wiley & Sons, Ltd.
Keywords: incubation times, log‐gamma distribution, truncated distributions, SARS
REFERENCES
- 1. Donnelly CA, Ghani AC, Leung GM, Hedley AJ, Fraser C, Riley S, Abu‐Raddad LJ, Ho LM, Thach T‐Q, Chau P, Chan K‐P, Lam T‐H, Tse L‐Y, Tsang T, Liu S‐H, Kong JHB, Lau EMC, Ferguson NM, Anderson RM. Epidemiological determinants of spread of causal agent of severe acute respiratory syndrome in Hong Kong. Lancet 2003; 361:1761–1766. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Bennett JH. (ed.). Statistical Inference and Analysis. Selected Correspondence of R.A. Fisher. Clarendon Press: Oxford, 1990. [Google Scholar]
- 3. Gupta AK, Nguyen TT, Wang Y. On maximum likelihood estimation of the binomial parameter n . Canadian Journal of Statistics 1999; 27:599–606. [Google Scholar]
- 4. Cox DR, Hinkley DV. Theoretical Statistics. Chapman & Hall: London, 1974. [Google Scholar]
- 5. Farewell VT, Prentice RL. A study of distributional shape in life testing. Technometrics 1977; 19:69–75. [Google Scholar]
- 6. Gore SM, Farewell VT. Extending public health surveillance of HIV disease. Statistics in Medicine 1993; 12:2061–2064. [PubMed] [Google Scholar]
- 7. Matthews DE, Farewell VT. On a singularity in the likelihood for a change‐point hazard rate model. Biometrika 1985; 72:703–704. [Google Scholar]
- 8. Aalen OO, Farewell VT, De Angelis D, Day NE, Gill ON. A Markov model for HIV disease progression including the effect of HIV diagnosis and treatment: application to AIDS prediction in England and Wales. Statistics in Medicine 1997; 16:2191–2210. [DOI] [PubMed] [Google Scholar]
- 9. Meltzer MI. Multiple contact dates and SARS incubation periods. Emerging Infectious Diseases 2004; 10:207–209. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Mood AM, Graybill FA, Boes DC. Introduction to the Theory of Statistics (3rd edn). McGraw‐Hill Kogakusha: Tokyo, 1974. [Google Scholar]