A simple approximate mathematical model to predict the number of severe acute respiratory syndrome cases and deaths

被引:38
作者
Choi, BCK
Pak, AWP
机构
[1] Univ Ottawa, Fac Med, Dept Epidemiol & Community Med, Ottawa, ON, Canada
[2] Univ Toronto, Fac Med, Dept Publ Hlth Sci, Toronto, ON, Canada
[3] Univ Ottawa, Inst Res & Planning, Ottawa, ON K1N 6N5, Canada
关键词
D O I
10.1136/jech.57.10.831
中图分类号
R1 [预防医学、卫生学];
学科分类号
1004 ; 120402 ;
摘要
Background: Severe acute respiratory syndrome (SARS) is currently spreading in many countries. This paper proposes a simple approximate mathematical model for public health practitioners to predict the number of SARS cases and deaths. Methods: The model is based on four parameters: R-o (basic reproductive number), F (case-fatality rate), i ( incubation period), and d (duration of disease). The calculations can be done by hand or by using a computer spreadsheet. Results: The best parameters to fit Canadian data as of 6 April 2003 ( before infection controls took effect) are R-o = 1.5, F = 30%, i = 5 days, d = 14 days. On 6 April ( day 40) there were 74 cases and 7 deaths. If this trend continues, SARS numbers in Canada are predicted to be as follows: 387 cases and 34 deaths by 26 April ( day 60), 4432 cases and 394 deaths by 26 May ( day 90), and 50 500 cases and 4489 deaths by 25 June ( day 120). By comparison, the best parameters to fit Hong Kong data as of 10 April 2003 are R-o = 2.0, F = 20%, i = 5 days, d = 14 days. Conclusions: Using the proposed mathematical model, it was estimated that about 1.5 to 2 new infectious cases were produced per infectious case every five days. Also, about 20% to 30% of the cases die within 14 days. The case-fatality may therefore be considerably higher than initially thought. The model indicates that SARS can spread very fast when there are no interventions.
引用
收藏
页码:831 / 835
页数:5
相关论文
共 17 条
[1]  
ANDERSON R M, 1991
[2]  
Beaglehole R., 1993, BASIC EPIDEMIOLOGY C, P97
[3]  
DONNELLY CA, 2003, LANCET 0507
[4]  
DRAZEN JM, 2003, N ENGL J MED 0331
[5]  
DROSTEN C, 2003, N ENGL J MED 0410
[6]  
FALSEY AR, 2003, LANCET 0408
[7]  
GERBERDING JL, 2003, N ENGL J MED 0402
[8]  
HALLORAN ME, 1998, MODERN EPIDEMIOLOGY, P519
[9]  
HAWALESHKA D, 2003, MACLEANS MAGAZI 0414
[10]  
KIAZEK TG, 2003, N ENGL J MED 0410