独
2003-05-13, 06:51 PM
Case fatality ratio
病死率
WHO has today revised its initial estimates of the case fatality ratio of SARS. The revision is based on an analysis of the latest data from Canada, China, Hong Kong SAR, Singapore, and Viet Nam.
WHO今天修订了它关于SARS病死率的最初估计。这次修订依据来自加拿大、中国、香港特别行政区、新加坡和越南的最新数据。
On the basis of more detailed and complete data, and more reliable methods, WHO now estimates that the case fatality ratio of SARS ranges from 0% to 50% depending on the age group affected, with an overall estimate of case fatality of 14% to 15%.
通过更详细和完全的数据以及更可靠的方法，WHO现在估计SARS病死率的范围在0%到50%之间，随感染的年龄组变化，整体估计死亡率为14%到15%。
The likelihood of dying from SARS in a given area has been shown to depend on the profile of the cases, including the age group most affected and the presence of underlying disease. Based on data received by WHO to date, the case fatality ratio is estimated to be less than 1% in persons aged 24 years or younger, 6% in persons aged 25 to 44 years, 15% in persons aged 45 to 64 years, and greater than 50% in persons aged 65 years and older.
某地区SARS致死的可能性取决于个案特性，包括最易感染的年龄组和潜在的其他疾病。根据WHO最新收到的数据，估计病例病死率在24岁或更年轻的人群里小于1%，25-44岁为6%， 45-64岁为15%，65岁或以上为50%。
A case fatality ratio measures the proportion of all people with a disease who will die from the disease. In other words, it measures the likelihood that a disease will kill its host, and is thus an important indicator of the severity of a disease and its significance as a public health problem. The likelihood that a person will die of SARS could be influenced by factors related to the SARS virus, the route of exposure and dose (amount) of virus, personal factors such as age or the presence of another disease, and access to prompt medical care.
病例病死率计量所有人群中死于所患疾病的比例。换句话说，它计量一种疾病杀死宿主的可能性，因此它是疾病严重程度的重要指标，也对公共卫生问题有深刻的影响。一个人因SARS致死的可能性可受以下因素的影响：SARS病毒，暴露途经和病毒剂量，个体因素如年龄或患其他疾病，以及是否有及时的医疗护理。
Many factors complicate efforts to calculate a case fatality ratio while an outbreak is still evolving. Deaths from SARS typically occur after several weeks of illness. Full recovery may take even longer. While an epidemic is still evolving, only some of the individuals affected by the disease will have died or recovered. Only at the end of an epidemic can an absolute value be calculated, taking into account total deaths, total recoveries and people lost to follow-up. Calculating case fatality as the number of deaths reported divided by the number of cases reported irrespective of the time elapsed since they became ill gives an underestimate of the true case fatality ratio.
疾病仍处于暴发期时很多因素使计算病例病死率的努力复杂化。SARS所致死亡一般都在疾病发生后数周。完全康复可能需要更长时间。当一种流行病仍在发展时，仅有一些被疾病感染的个体会死亡或痊愈。仅当疾病流行结束时绝对值才会统计出来，包括死亡、痊愈和失访的总数。仅用报告的死亡数除以报告的病例数而不考虑发病仍在继续，这样统计的病例病死率将低于真实的病死率。
One method of overcoming this difficulty is to calculate the case fatality ratio using only those cases whose final outcome C died or recovered C is known. However, this method, when applied before an outbreak is over, gives an overestimate because the average time from illness onset to death for SARS is shorter than the average time from illness onset to recovery.
一种克服这个困难的方法是仅用那些最终已知的病例－死亡或痊愈－来统计。然而，当用于疾病发作结束之前时，这种方法将高估病死率，因为从SARS发病开始到死亡的平均时间比从发病开始到痊愈的平均时间要短。
With these methods, estimates of the case fatality ratio range from 11% to 17% in Hong Kong, from 13% to 15% in Singapore, from 15% to 19% in Canada, and from 5% to 13% in China.
用这些方法估计的病死率，香港为11%-17%，新加坡为13%-15%，中国为5%-13%。
A more accurate and unbiased estimation of case fatality for SARS can be obtained with a third method, survival analysis. This method relies on detailed individual data on the time from illness onset to death or full recovery, or time since illness onset for current cases. Using this method, WHO estimates that the case fatality ratio is 14% in Singapore and 15% in Hong Kong.
一种对SARS病例病死率更准确和广为接受的估计可以用第三种方法即生存分析得到。这种方法建立在详细的个体数据上－依据从疾病开始到死亡或痊愈的时间，或当前病例持续的时间。用这种方法，WHO估计病死率在新加坡为14%，在香港为15%。
In Viet Nam, where SARS has been contained and measurement is more straightforward, case fatality was comparatively low, at 8%. One explanation for this is the large number of total cases that occurred in younger, previously healthy health care workers.
在越南，SARS已得到控制，统计也更直接，病例病死率相对较低，为8%。对此的一种解释是，总病例中的大部分发生于年轻的，以前健康的卫生工作者。
Incubation period
潜伏期
WHO has also reviewed estimates of the incubation period of SARS, using individual case data. On the basis of this review, WHO continues to conclude that the current best estimate of the maximum incubation period is 10 days.
WHO也用个体病例数据修订了对SARS潜伏期的估计。根据这个修订，WHO仍然认为目前对最长潜伏期最准确的估计是10天。
The incubation period, which is the time from exposure to a causative agent to onset of disease, is particularly important as it forms the basis for many recommended control measures, including contact tracing and the duration of home isolation for contacts of probable SARS cases. Knowledge about the incubation period can also help physicians make diagnostic decisions about whether the presenting symptoms and clinical history of a patient point to SARS or to some other disease.
潜伏期，即从接触致病体到开始发病的时间，因它形成许多推荐的控制措施而特别重要，包括跟踪接触史和对SARS疑似病例的接触者的家庭隔离时间。对潜伏期的了解也有助于医生对患者的表现症状和临床史是否与SARS还是与其他疾病有关做出诊断。
The incubation period can vary from one case to another according to the route by which the person was exposed, the dose of virus received, and other factors, including immune status. Estimates of the incubation period are further complicated by the fact that some patients have had opportunities for multiple exposures to the virus. The particular exposure that caused disease may prove impossible to determine. For these reasons, the most reliable estimates of the incubation period are based on a study of cases having a single documented exposure to a known case.
根据个人暴露于疾病的途经，感染病毒的剂量和包括免疫状况的其他因素的不同，潜伏期将不同。 一些患者数次接触病毒使预计潜伏期变得复杂化。究竟哪次接触病毒而致病也许最终无法确定。因此，对潜伏期最可靠的估计应根据对某个已知病例有记录的接触的研究。
In today’s review, WHO has analysed the incubation periods of individuals with well-defined single-point exposures in Singapore, Canada, and Europe. Findings support the original estimate of 10 days as the maximum incubation period.
在今天的修订中，WHO分析了新加坡、加拿大和欧洲的严格记录的一次性接触个体的潜伏期。其中的发现支持原来最长潜伏期为10天的估计。
However, one recently published analysis of data from Hong Kong estimates a longer maximum incubation period in a group of 57 patients. This analysis, which may be significant and important for disease control, will be studied in more detail. The longer incubation period could reflect differences in methodology, specificity of diagnosis, route of transmission, infectious dose, or other factors. Reliable diagnosis C determining that all cases diagnosed as SARS are true cases of the disease C has been particularly difficult to establish in this outbreak, as diagnosis is made based on a set of non-specific symptoms and clinical signs that are seen in several other diseases.
然而，最近一个来自香港的已发表的分析数据估计在一组57人的患者中有更长的最大潜伏期。这个分析也许对疾病控制重要而意义深远，将被进一步研究。更长的潜伏期可能反映了方法学、诊断的确切性、传播途经、感染剂量或其他因素的不同。确定所有诊断为SARS的病例为真实病例的可靠诊断在这次暴发中实现起来特别困难，因为诊断依靠几种其他疾病常见的一系列非典型症状和临床表现。
Prompt isolation
及时隔离
WHO continues to recommend the earliest possible isolation of all suspect and probable cases of SARS. A short time between onset of symptoms and isolation reduces opportunities for transmission to others. It also reduces the number of contacts requiring active follow-up, and thus helps relieve some of the burden on health services. In addition, prompt hospitalization gives patients the best chance of receiving possibly life-saving care should their condition take a critical course.
WHO继续推荐尽早隔离所有SARS疑似病例。从隔离到出现症状的一小段时间内就减少了传播给他人的机会。隔离也减少因为接触疾病而需要的积极跟踪，由此减轻一些医疗服务负担。另外，及时住院给予患者最好的护理机会，如果他们的病情危急，这种护理也许起到挽救生命的作用。
（原文摘自WHO网站）
病死率
WHO has today revised its initial estimates of the case fatality ratio of SARS. The revision is based on an analysis of the latest data from Canada, China, Hong Kong SAR, Singapore, and Viet Nam.
WHO今天修订了它关于SARS病死率的最初估计。这次修订依据来自加拿大、中国、香港特别行政区、新加坡和越南的最新数据。
On the basis of more detailed and complete data, and more reliable methods, WHO now estimates that the case fatality ratio of SARS ranges from 0% to 50% depending on the age group affected, with an overall estimate of case fatality of 14% to 15%.
通过更详细和完全的数据以及更可靠的方法，WHO现在估计SARS病死率的范围在0%到50%之间，随感染的年龄组变化，整体估计死亡率为14%到15%。
The likelihood of dying from SARS in a given area has been shown to depend on the profile of the cases, including the age group most affected and the presence of underlying disease. Based on data received by WHO to date, the case fatality ratio is estimated to be less than 1% in persons aged 24 years or younger, 6% in persons aged 25 to 44 years, 15% in persons aged 45 to 64 years, and greater than 50% in persons aged 65 years and older.
某地区SARS致死的可能性取决于个案特性，包括最易感染的年龄组和潜在的其他疾病。根据WHO最新收到的数据，估计病例病死率在24岁或更年轻的人群里小于1%，25-44岁为6%， 45-64岁为15%，65岁或以上为50%。
A case fatality ratio measures the proportion of all people with a disease who will die from the disease. In other words, it measures the likelihood that a disease will kill its host, and is thus an important indicator of the severity of a disease and its significance as a public health problem. The likelihood that a person will die of SARS could be influenced by factors related to the SARS virus, the route of exposure and dose (amount) of virus, personal factors such as age or the presence of another disease, and access to prompt medical care.
病例病死率计量所有人群中死于所患疾病的比例。换句话说，它计量一种疾病杀死宿主的可能性，因此它是疾病严重程度的重要指标，也对公共卫生问题有深刻的影响。一个人因SARS致死的可能性可受以下因素的影响：SARS病毒，暴露途经和病毒剂量，个体因素如年龄或患其他疾病，以及是否有及时的医疗护理。
Many factors complicate efforts to calculate a case fatality ratio while an outbreak is still evolving. Deaths from SARS typically occur after several weeks of illness. Full recovery may take even longer. While an epidemic is still evolving, only some of the individuals affected by the disease will have died or recovered. Only at the end of an epidemic can an absolute value be calculated, taking into account total deaths, total recoveries and people lost to follow-up. Calculating case fatality as the number of deaths reported divided by the number of cases reported irrespective of the time elapsed since they became ill gives an underestimate of the true case fatality ratio.
疾病仍处于暴发期时很多因素使计算病例病死率的努力复杂化。SARS所致死亡一般都在疾病发生后数周。完全康复可能需要更长时间。当一种流行病仍在发展时，仅有一些被疾病感染的个体会死亡或痊愈。仅当疾病流行结束时绝对值才会统计出来，包括死亡、痊愈和失访的总数。仅用报告的死亡数除以报告的病例数而不考虑发病仍在继续，这样统计的病例病死率将低于真实的病死率。
One method of overcoming this difficulty is to calculate the case fatality ratio using only those cases whose final outcome C died or recovered C is known. However, this method, when applied before an outbreak is over, gives an overestimate because the average time from illness onset to death for SARS is shorter than the average time from illness onset to recovery.
一种克服这个困难的方法是仅用那些最终已知的病例－死亡或痊愈－来统计。然而，当用于疾病发作结束之前时，这种方法将高估病死率，因为从SARS发病开始到死亡的平均时间比从发病开始到痊愈的平均时间要短。
With these methods, estimates of the case fatality ratio range from 11% to 17% in Hong Kong, from 13% to 15% in Singapore, from 15% to 19% in Canada, and from 5% to 13% in China.
用这些方法估计的病死率，香港为11%-17%，新加坡为13%-15%，中国为5%-13%。
A more accurate and unbiased estimation of case fatality for SARS can be obtained with a third method, survival analysis. This method relies on detailed individual data on the time from illness onset to death or full recovery, or time since illness onset for current cases. Using this method, WHO estimates that the case fatality ratio is 14% in Singapore and 15% in Hong Kong.
一种对SARS病例病死率更准确和广为接受的估计可以用第三种方法即生存分析得到。这种方法建立在详细的个体数据上－依据从疾病开始到死亡或痊愈的时间，或当前病例持续的时间。用这种方法，WHO估计病死率在新加坡为14%，在香港为15%。
In Viet Nam, where SARS has been contained and measurement is more straightforward, case fatality was comparatively low, at 8%. One explanation for this is the large number of total cases that occurred in younger, previously healthy health care workers.
在越南，SARS已得到控制，统计也更直接，病例病死率相对较低，为8%。对此的一种解释是，总病例中的大部分发生于年轻的，以前健康的卫生工作者。
Incubation period
潜伏期
WHO has also reviewed estimates of the incubation period of SARS, using individual case data. On the basis of this review, WHO continues to conclude that the current best estimate of the maximum incubation period is 10 days.
WHO也用个体病例数据修订了对SARS潜伏期的估计。根据这个修订，WHO仍然认为目前对最长潜伏期最准确的估计是10天。
The incubation period, which is the time from exposure to a causative agent to onset of disease, is particularly important as it forms the basis for many recommended control measures, including contact tracing and the duration of home isolation for contacts of probable SARS cases. Knowledge about the incubation period can also help physicians make diagnostic decisions about whether the presenting symptoms and clinical history of a patient point to SARS or to some other disease.
潜伏期，即从接触致病体到开始发病的时间，因它形成许多推荐的控制措施而特别重要，包括跟踪接触史和对SARS疑似病例的接触者的家庭隔离时间。对潜伏期的了解也有助于医生对患者的表现症状和临床史是否与SARS还是与其他疾病有关做出诊断。
The incubation period can vary from one case to another according to the route by which the person was exposed, the dose of virus received, and other factors, including immune status. Estimates of the incubation period are further complicated by the fact that some patients have had opportunities for multiple exposures to the virus. The particular exposure that caused disease may prove impossible to determine. For these reasons, the most reliable estimates of the incubation period are based on a study of cases having a single documented exposure to a known case.
根据个人暴露于疾病的途经，感染病毒的剂量和包括免疫状况的其他因素的不同，潜伏期将不同。 一些患者数次接触病毒使预计潜伏期变得复杂化。究竟哪次接触病毒而致病也许最终无法确定。因此，对潜伏期最可靠的估计应根据对某个已知病例有记录的接触的研究。
In today’s review, WHO has analysed the incubation periods of individuals with well-defined single-point exposures in Singapore, Canada, and Europe. Findings support the original estimate of 10 days as the maximum incubation period.
在今天的修订中，WHO分析了新加坡、加拿大和欧洲的严格记录的一次性接触个体的潜伏期。其中的发现支持原来最长潜伏期为10天的估计。
However, one recently published analysis of data from Hong Kong estimates a longer maximum incubation period in a group of 57 patients. This analysis, which may be significant and important for disease control, will be studied in more detail. The longer incubation period could reflect differences in methodology, specificity of diagnosis, route of transmission, infectious dose, or other factors. Reliable diagnosis C determining that all cases diagnosed as SARS are true cases of the disease C has been particularly difficult to establish in this outbreak, as diagnosis is made based on a set of non-specific symptoms and clinical signs that are seen in several other diseases.
然而，最近一个来自香港的已发表的分析数据估计在一组57人的患者中有更长的最大潜伏期。这个分析也许对疾病控制重要而意义深远，将被进一步研究。更长的潜伏期可能反映了方法学、诊断的确切性、传播途经、感染剂量或其他因素的不同。确定所有诊断为SARS的病例为真实病例的可靠诊断在这次暴发中实现起来特别困难，因为诊断依靠几种其他疾病常见的一系列非典型症状和临床表现。
Prompt isolation
及时隔离
WHO continues to recommend the earliest possible isolation of all suspect and probable cases of SARS. A short time between onset of symptoms and isolation reduces opportunities for transmission to others. It also reduces the number of contacts requiring active follow-up, and thus helps relieve some of the burden on health services. In addition, prompt hospitalization gives patients the best chance of receiving possibly life-saving care should their condition take a critical course.
WHO继续推荐尽早隔离所有SARS疑似病例。从隔离到出现症状的一小段时间内就减少了传播给他人的机会。隔离也减少因为接触疾病而需要的积极跟踪，由此减轻一些医疗服务负担。另外，及时住院给予患者最好的护理机会，如果他们的病情危急，这种护理也许起到挽救生命的作用。
（原文摘自WHO网站）