{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T12:29:33Z","timestamp":1791116973267,"version":"4.1.0"},"reference-count":18,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5547","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[2001,11,23]]},"abstract":"<jats:p>The size of the variant Creutzfeldt-Jakob Disease (vCJD) epidemic in the United Kingdom is a major public health concern and a subject of speculation. The cases are young (mean age = 28). Assuming that the risk of developing the disease in susceptible exposed subjects decreases exponentially with age after age 15, that all infections occurred between 1980 and 1989, and that the distribution of the incubation period is lognormal, we estimate that the mean duration of the incubation period is 16.7 years [95% confidence interval (CI): 12.4 to 23.2] and that the total number of cases will be 205 (upper limit of the 95% CI: 403).<\/jats:p>","DOI":"10.1126\/science.1066838","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T09:47:15Z","timestamp":1027763235000},"page":"1726-1728","source":"Crossref","is-referenced-by-count":174,"title":["Estimation of Epidemic Size and Incubation Time Based on Age Characteristics of vCJD in the United Kingdom"],"prefix":"10.1126","volume":"294","author":[{"given":"Alain-Jacques","family":"Valleron","sequence":"first","affiliation":[{"name":"Epidemiology and Information Sciences, INSERM U444, CHU Saint-Antoine, Universite\u0301 Pierre et Marie Curie et Assistance Publique\u2013Ho\u0302pitaux de Paris, 27 rue Chaligny, 75012 Paris, France."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pierre-Yves","family":"Boelle","sequence":"additional","affiliation":[{"name":"Epidemiology and Information Sciences, INSERM U444, CHU Saint-Antoine, Universite\u0301 Pierre et Marie Curie et Assistance Publique\u2013Ho\u0302pitaux de Paris, 27 rue Chaligny, 75012 Paris, France."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Will","sequence":"additional","affiliation":[{"name":"National Creutzfeldt-Jakob Disease Surveillance Unit, Western General Hospital, Edinburgh EH4 2XU, UK."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jean-Yves","family":"Cesbron","sequence":"additional","affiliation":[{"name":"Immunite\u0301 Anti-Infectieuse JE 2236, UFR de Me\u0301decine de Grenoble, Universite\u0301 Joseph Fourier, Domaine de la Merci, 38706 La Tronche, France."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","doi-asserted-by":"publisher","DOI":"10.1038\/39057"},{"key":"e_1_3_1_3_2","doi-asserted-by":"crossref","unstructured":"N. M. Ferguson C. A. Donnelly M. E. J. Woolhouse R. M. Anderson Philos. Trans. R. Soc. London Ser. B Biol. Sci. 352 803 (1997).","DOI":"10.1098\/rstb.1997.0063"},{"key":"e_1_3_1_4_2","doi-asserted-by":"publisher","DOI":"10.1093\/ije\/28.3.526"},{"key":"e_1_3_1_5_2","unstructured":"\u201cOpinion of the scientific steering committee on the human exposure risk (HER) via food with respect to BSE\u201d (European Union Scientific Steering Committee 10 December 1999)"},{"key":"e_1_3_1_6_2","doi-asserted-by":"publisher","DOI":"10.1038\/385197a0"},{"key":"e_1_3_1_7_2","doi-asserted-by":"publisher","DOI":"10.1038\/35020688"},{"key":"e_1_3_1_8_2","unstructured":"Surveillance data collected by the UK Creutzfeldt-Jakob Disease Surveillance Unit are available at www.cjd.ed.ac.uk\/."},{"key":"e_1_3_1_9_2","doi-asserted-by":"publisher","DOI":"10.1136\/jech.46.6.582"},{"key":"e_1_3_1_10_2","unstructured":"The \u201cforce of infection\u201d is defined in mathematical epidemiology to quantify the risk per unit of time (usually the year) that a susceptible individual has to acquire the disease after being exposed to the infectious agent. For a complete review of the concept of force of infection see R. M. Anderson and R. May [ Infectious Diseases of Humans: Dynamics and Control (Oxford Science Publications Oxford 1991) chaps. 3 and 8]."},{"key":"e_1_3_1_11_2","unstructured":"Supplemental materials are available at Science Online at www.sciencemag.org\/cgi\/content\/full\/294\/5547\/1726\/DC1."},{"key":"e_1_3_1_12_2","unstructured":"The function f ( a ) was taken in the form f ( a ) = 0 if a < 0.5 as infants younger than 0.5 year were assumed to not be exposed to the BSE agent; f ( a ) = \u03bb 0 if 0.5 < a <15 which corresponds to the constant risk assumed in children before 15; and f ( a ) = \u03bb 0 e \u2212\u03b1(a\u22120.5) if a > 15. The function g ( t ) was chosen to reflect the increasing probability of the presence of contaminated meat products in the human diet in parallel to the increasing incidence of BSE in animals over the period 1980\u201389. Possible exposures after 1989 were not considered in this analysis. Mimicking the incidence profile observed in the BSE epidemic during the same period we set g ( t ) = \u03b3 0 e \u2212\u03b3( t \u22121989) . From the knowledge of the doubling time observed in the BSE epidemic (14 months) during the 1980\u201388 period (2) we extrapolate \u03b3 = ln(2)\/(14\/12) = 0.596. As only the product \u03bb 0 \u03b3 0 was identifiable because of the form for the force of infection we fixed \u03b3 0 at 1."},{"key":"e_1_3_1_13_2","first-page":"310","volume":"51","author":"Sartwell P. E.","year":"1950","unstructured":"Sartwell P. E., Am. J. Hyg. 51, 310 (1950).","journal-title":"Am. J. Hyg."},{"key":"e_1_3_1_14_2","doi-asserted-by":"publisher","DOI":"10.2307\/2530689"},{"key":"e_1_3_1_15_2","unstructured":"P(t a)dtda=S(t a)\u222b0a\u2009exp\u2212\u222b0v\u2009\u03bb(t\u2212u u)du\n\u03bb(t\u2212v v)h(a\u2212v)dvdtda\nThe log-likelihood of the observed cases is  \n\u2211i\u2009logsP(ti ai)\u2212\u222b\u222bD\u2009sP(t a)dadt where the first sum is over all observed cases and the integration is made in the domain D corresponding to ages between 0.5 and 100 years and to years between 1980 and 2000. s is the intensity of the Poisson birth process. Numerical maximization of the likelihood was done with a modified Levenberg Marquardt algorithm (SLATEC) after reparameterization of the model A logarithmic transformation was used for all variables but incubation mean time. The maximization was independently performed with a Newton-Raphson method (NAG) and all presented results were in agreement in the two methods with differences between estimates of less than 10 \u22122 . Numerical integrations were carried out to a precision of 10 \u22124 ."},{"key":"e_1_3_1_16_2","doi-asserted-by":"crossref","unstructured":"J. Huillard d'Aignaux et al. Neurology 53 1197 (1999).","DOI":"10.1212\/WNL.53.6.1197"},{"key":"e_1_3_1_17_2","doi-asserted-by":"publisher","DOI":"10.1159\/000110837"},{"key":"e_1_3_1_18_2","unstructured":"The figure obtained from the Cousens model when an incubation period of mean 15 years and 95th percentile of 22 years are assumed."},{"key":"e_1_3_1_19_2","unstructured":"We thank J. Gagnon for helpful discussions."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.1066838","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,9]],"date-time":"2024-01-09T21:46:50Z","timestamp":1704836810000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.1066838"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2001,11,23]]},"references-count":18,"journal-issue":{"issue":"5547","published-print":{"date-parts":[[2001,11,23]]}},"alternative-id":["10.1126\/science.1066838"],"URL":"https:\/\/doi.org\/10.1126\/science.1066838","relation":{},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2001,11,23]]}}}