SARS-associated coronavirus transmission, United States

To better assess the risk for transmission of the severe acute respiratory syndrome-associated coronavirus (SARS-CoV), we obtained serial specimens and clinical and exposure data from seven confirmed U.S. SARS patients and their 10 household contacts. SARS-CoV was detected in a day-14 sputum specimen from one case-patient and in five stool specimens from two case-patients. In one case-patient, SARS-CoV persisted in stool for at least 26 days after symptom onset. The highest amounts of virus were in the day-14 sputum sample and a day-14 stool sample. Residual respiratory symptoms were still present in recovered SARS case-patients 2 months after illness onset. Possible transmission of SARS-CoV occurred in one household contact, but this person had also traveled to a SARS-affected area. The data suggest that SARS-CoV is not always transmitted efficiently. Routine collection and testing of stool and sputum specimens of probable SARS case-patients may help the early detection of SARS-CoV infection.     

Possible SARS coronavirus transmission during cardiopulmonary resuscitation

Infection of healthcare workers with the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is thought to occur primarily by either contact or large respiratory droplet transmission. However, infrequent healthcare worker infections occurred despite the use of contact and droplet precautions, particularly during certain aerosol-generating medical procedures. We investigated a possible cluster of SARS-CoV infections in healthcare workers who used contact and droplet precautions during attempted cardiopulmonary resuscitation of a SARS patient. Unlike previously reported instances of transmission during aerosol-generating procedures, the index case-patient was unresponsive, and the intubation procedure was performed quickly and without difficulty. However, before intubation, the patient was ventilated with a bag-valve-mask that may have contributed to aerosolization of SARS-CoV. On the basis of the results of this investigation and previous reports of SARS transmission during aerosol-generating procedures, a systematic approach to the problem is outlined, including the use of the following: 1) administrative controls, 2) environmental engineering controls, 3) personal protective equipment, and 4) quality control.     

Seroprevalence of SARS coronavirus antibody in household contacts

Between March and July 2003, 671 cases of severe acute respiratory syndrome (SARS) were diagnosed in Taiwan with a total of 84 fatalities. After the epidemic, a serological survey was conducted involving the asymptomatic household contacts. Household contacts of 13 index patients were enrolled in the study. Contact history and clinical symptoms of the household contacts were recorded by standardized questionnaires. Blood samples of patients and household contacts were collected at least 28 days after symptom onset in the index patients or household exposure in the contacts for SARS-associated coronavirus (SARS-CoV) IgG testing. On the basis of this investigation, 29 persons (25 adults and 4 children) were identified as having had unprotected exposure to the index cases before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-CoV infection to any contacts. This investigation demonstrated that subclinical transmission among household contacts was low in the described setting.     

SARS transmission in Vietnam outside of the health-care setting

To evaluate the risk of transmission of SARS coronavirus outside of the health-care setting, close household and community contacts of laboratory-confirmed SARS cases were identified and followed up for clinical and laboratory evidence of SARS infection. Individual- and household-level risk factors for transmission were investigated. Nine persons with serological evidence of SARS infection were identified amongst 212 close contacts of 45 laboratory-confirmed SARS cases (secondary attack rate 4.2%, 95% CI 1.5-7). In this cohort, the average number of secondary infections caused by a single infectious case was 0.2. Two community contacts with laboratory evidence of SARS coronavirus infection had mild or sub-clinical infection, representing 3% (2/65) of Vietnamese SARS cases. There was no evidence of transmission of infection before symptom onset. Physically caring for a symptomatic laboratory-confirmed SARS case was the only independent risk factor for SARS transmission (OR 5.78, 95% CI 1.23-24.24).     

Lack of SARS transmission among healthcare workers, United States

Healthcare workers accounted for a large proportion of persons with severe acute respiratory syndrome (SARS) during the worldwide epidemic of early 2003. We conducted an investigation of healthcare workers exposed to laboratory-confirmed SARS patients in the United States to evaluate infection-control practices and possible SARS-associated coronavirus (SARS-CoV) transmission. We identified 110 healthcare workers with exposure within droplet range (i.e., 3 feet) to six SARS-CoV-positive patients. Forty-five healthcare workers had exposure without any mask use, 72 had exposure without eye protection, and 40 reported direct skin-to-skin contact. Potential droplet- and aerosol-generating procedures were infrequent: 5% of healthcare workers manipulated a patient's airway, and 4% administered aerosolized medication. Despite numerous unprotected exposures, there was no serologic evidence of healthcare-related SARS-CoV transmission. Lack of transmission in the United States may be related to the relative absence of high-risk procedures or patients, factors that may place healthcare workers at higher risk for infection.     

Risk factors for SARS among persons without known contact with SARS patients, Beijing, China

Most cases of severe acute respiratory syndrome (SARS) have occurred in close contacts of SARS patients. However, in Beijing, a large proportion of SARS cases occurred in persons without such contact. We conducted a case-control study in Beijing that compared exposures of 94 unlinked, probable SARS patients with those of 281 community-based controls matched for age group and sex. Case-patients were more likely than controls to have chronic medical conditions or to have visited fever clinics (clinics at which possible SARS patients were separated from other patients), eaten outside the home, or taken taxis frequently. The use of masks was strongly protective. Among 31 case-patients for whom convalescent-phase (>21 days) sera were available, 26% had immunoglobulin G to SARS-associated coronavirus. Our finding that clinical SARS was associated with visits to fever clinics supports Beijing's strategy of closing clinics with poor infection-control measures. Our finding that mask use lowered the risk for disease supports the community's use of this strategy.     

广东省不同人群SARS病毒抗体水平调查

目的对不同人群进行SARS-IgG抗体水平检测，分析SARS流行规模和特征，评价暴露的危险性，了解人数中是否存在SARS病毒隐性感染，为寻找SARS病毒传染源提供线索。方法抽取7708份不同人群标本，按临床症状和暴露因素分为临床确诊SARS病人、病人或污染物的接触者、普通健康人群和动物销售人员4类，采用酶联免疫方法(ELISA)进行SARS-IgG抗体检测，用免疫荧光法(IFA)复核，并结合流行病学资料进行分析。结果127例临床确诊SARS病人抗体阳性率为66．9％；密切接触者中女性发病率高于男性；SARS病人或其污染物的密切接触者抗体阳性率为0．88％；动物销售人员为13．4％；野生哺乳动物销售者的抗体阳性率显著高于其他动物销售者，普通健康人群未检出抗体阳性。低年龄健康人群ELISA检测阳性率为2．06％，高于总体水平。结论人群总体抗体水平很低，普通健康人群无SARS冠状病毒抗体，但可能存在某种可与SARS冠状病毒起交叉反应的抗体；有无接触史是影响抗体阳性率的重要因素；密切接触者可能存在隐性感染；野生动物可能是本次SARS的传染源。     

Superspreading SARS events, Beijing, 2003

Superspreading events were pivotal in the global spread of severe acute respiratory syndrome (SARS). We investigated superspreading in one transmission chain early in Beijing's epidemic. Superspreading was defined as transmission of SARS to at least eight contacts. An index patient with onset of SARS 2 months after hospital admission was the source of four generations of transmission to 76 case-patients, including 12 healthcare workers and several hospital visitors. Four (5%) case circumstances met the superspreading definition. Superspreading appeared to be associated with older age (mean 56 vs. 44 years), case fatality (75% vs. 16%, p = 0.02, Fisher exact test), number of close contacts (36 vs. 0.37) and attack rate among close contacts (43% vs. 18.5%, p < 0.025). Delayed recognition of SARS in a hospitalized patient permitted transmission to patients, visitors, and healthcare workers. Older age and number of contacts merit investigation in future studies of superspreading.     

Lack of Transmission among Close Contacts of Patient with Case of Middle East Respiratory Syndrome Imported into the United States, 2014

In May 2014, a traveler from the Kingdom of Saudi Arabia was the first person identified with Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States. To evaluate transmission risk, we determined the type, duration, and frequency of patient contact among health care personnel (HCP), household, and community contacts by using standard questionnaires and, for HCP, global positioning system (GPS) tracer tag logs. Respiratory and serum samples from all contacts were tested for MERS-CoV. Of 61 identified contacts, 56 were interviewed. HCP exposures occurred most frequently in the emergency department (69%) and among nurses (47%); some HCP had contact with respiratory secretions. Household and community contacts had brief contact (e.g., hugging). All laboratory test results were negative for MERS-CoV. This contact investigation found no secondary cases, despite case-patient contact by 61 persons, and provides useful information about MERS-CoV transmission risk. Compared with GPS tracer tag recordings, self-reported contact may not be as accurate.     

一起SARS爆发的血清流行病学调查

目的 探讨SARS密切接触者的隐性感染和SARS患者血清中特异性抗体的消长情况。方法 采用中和试验法、间接酶联免疫吸附试验(ELISA)和免疫粘连法对北京一起SARS爆发案例中与重症SARS患者无防护密切接触的未发病者和续发SARS病例进行血清SARS特异性IgG抗体检测,采血时间为发病后或接触后24周左右。结果 共采集到32份血清,其中未发病密切接触者的血清19份,SARS康复期患者血清13份。三种方法检测结果:57份次未发病密切接触者的血清标本SARS-CoV抗体检测,结果均为阴性;39份次SARS康复期患者血清标本SARS-CoV抗体检测,38份次结果为阳性,1份次(用免疫粘连法检测)结果为阴性。病后24周左右的中和抗体效价为1:43(1:16～1:203)。结论 研究中未发现SARS密切接触者存在隐性感染;SARS患者病后24周左右血清IgG抗体仍维持在较高水平。     

Revised U.S. surveillance case definition for severe acute respiratory syndrome (SARS) and update on SARS cases--United States and worldwide, December 2003

During the 2003 epidemic of severe acute respiratory syndrome (SARS), CDC and the Council of State and Territorial Epidemiologists (CSTE) developed surveillance criteria to identify persons with SARS. The surveillance case definition changed throughout the epidemic as understanding of the clinical, laboratory, and transmission characteristics of SARS-associated coronavirus (SARS-CoV) increased. On June 26, CSTE adopted a position statement to add SARS-CoV disease to the National Notifiable Disease Surveillance System (NNDSS). The position statement included criteria for defining a SARS case for national reporting. On November 3, CSTE issued a new interim position statement with a revised SARS case definition. This report summarizes the new U.S. surveillance case definition for SARS and updates reported cases of SARS worldwide and in the United States.     

Cluster of SARS among medical students exposed to single patient, Hong Kong

We studied transmission patterns of severe acute respiratory syndrome (SARS) among medical students exposed exclusively to the first SARS patient in the Prince of Wales Hospital in Hong Kong, before his illness was recognized. We conducted a retrospective cohort study of 66 medical students who visited the index patient's ward, including 16 students with SARS and 50 healthy students. The risk of contracting SARS was sevenfold greater among students who definitely visited the index case's cubicle than in those who did not (10/27 [41%] versus 1/20 [5%], relative risk 7.4; 95% confidence interval 1.0 to 53.3). Illness rates increased directly with proximity of exposure to the index case. However, four of eight students who were in the same cubicle, but were not within 1 m of the index case-patient, contracted SARS. Proximity to the index case-patient was associated with transmission, which is consistent with droplet spread. Transmission through fomites or small aerosols cannot be ruled out.     

合肥市首例输入性SARS病例流行病学调查分析

目的　分析SARS病例的传染性和传播特征 ,为控制SARS流行提供依据。方法　采用调查表 ,用查阅病历、面对面调查和电话调查相结合方式进行个案调查和线索追踪。按照接触方式分析传染源、接触关系和暴露后的危险性。结果　共追查到与本案例相关的密切接触者 115人 ,发病 2例 ,死亡 1例 ,总罹患率为 1.74 %。第二代病例死亡时间在密切接触者集中接触时间。无防护的密切接触者有被感染发病的危险性。SARS疫情经及时采取综合性措施得到控制。结论　本次SARS的感染来源于实验室。SARS接触过程中的医院聚集性应予以关注。     

一起传染性非典型肺炎爆发的“超级传播者”和传播链分析

目的：了解严重急性呼吸综合征(SARS)爆发案例的传播过程，分析SARS病例不同阶段的传染性和不同接触方式的危险性。方法：设计统一调查表，用查阅病历、面对面调查和电话调查相结合的方式进行，以指征病例为起点进行线索追踪和个案调查。用传播链示意图分析传播关系，用接触史分析示意图分析传染性。结果：共追查到与该案例传播链相关的接触者207人，发病36例，死亡1例，总罹患率为17％。其中指征病例和1名二代病例分别直接传播了12例和13例续发病例，其传播过程可以用清晰的传播链加以描述；所有36例病例均与前代病例的症状期有密切接触史，家族传播链中85％的病例都与前代病例症状期的第3—5天有过接触，发病前后均接触和仅发病后接触者罹患率分别为70％和67％，差异无显著性；仅与前代病例潜伏期接触的15名同柜台同事、29名同班同学无发病，38名与医护人员发病前或发病初期密切接触的家属无发病。结论：该案例所有的续发病例都有与症状期病例密切接触史；未观察到SARS患者在其潜伏期内存在传染性。     

不同地区人群SARS血清流行病学调查

目的分析严重急性呼吸综合征(Severe Acute Respiratory Syndrome，SARS)流行期间不同地区人群及SARS临床诊断病例血清特异性抗体(SARS-CoV IgG)变化规律以及健康人群是否存在隐性感染。方法采用酶联免疫方法(ELISA)及间接免疫荧光法(IFA)，对香港、澳门、北京、广州地区1453名健康人及广州和北京地区257例SARS临床诊断病例进行血清SARS—CoV IgG抗体检测，并跟踪检测患者病后不同时间(发病3～270d)血清抗体变化情况。结果4个地区健康人群(包括160名密切接触者)中，用ELISA法检出2例SARS—CoV IgG抗体阳性，阳性者进一步用IFA检测则为阴性；广州地区200名健康体检者同时采用ELISA和IFA检测，结果均为阴性。ELISA和IFA同时检测257例临床诊断病例发病20d后的血清SARS—CoV IgG抗体，2种方法检出的阳性率均为90％。ELISA法跟踪检测257例临床诊断病例发病后3～270d血清IgG抗体，抗体滴度在发病后4～6个月内随时间延长逐渐升高，多数病人抗体在第4～6个月达到高峰，并持续到第8个月，部分病人抗体达高峰后开始下降，但至第9个月仍阳性。结论健康人群中隐性感染率极低，血清SARS—CoV IgG抗体在病程后期有诊断价值，血清特异性抗体可持续9个月以上。     

北京市SARS患者密切接触者发病及其危险因素分析

目的 了解SARS密切接触者的发病危险因素。方法 采用回顾性流行病学方法,分析已有的SARS疫情及密切接触者的流行病学资料,利用SPSS统计软件对现有资料进行统计学分析。结果 在北京市5个区县的2195个密切接触者中,转归为病例138例,罹患率为6.3％。与病例为同事、同学关系,罹患率仅为0.36％。家务待业病例的密切接触者罹患率为最高(15.33％),接触地点在家和医院的密切接触者罹患率为31.71％,接触地点在学校密切接触者罹患率为0.77％。而接触地点在工作单位的密切接触者459名中,无一例转为病例,罹患率为零。结论 密切接触者发病的影响因素与患者接触时间、接触程度与频率、接触地点、隔离方式、时间及密切接触者的年龄等有关。SARS的传播途径存在近距离密切接触传播及家庭聚集性感染。科学管理密切接触者是控制SARS疫情蔓延的有效措施。     

Quarantine for SARS, Taiwan

During the 2003 outbreak of severe acute respiratory syndrome (SARS) in Taiwan, >150,000 persons were quarantined, 24 of whom were later found to have laboratory-confirmed SARS-coronavirus (SARS-CoV) infection. Since no evidence exists that SARS-CoV is infective before the onset of symptoms and the quarantined persons were exposed but not symptomatic, we thought the quarantine's effectiveness should be investigated. Using the Taiwan quarantine data, we found that the onset-to-diagnosis time of previously quarantined confirmed case-patients was significantly shortened compared to that for those who had not been quarantined. Thus, quarantine for SARS in Taiwan screened potentially infective persons for swift diagnosis and hospitalization after onset, thereby indirectly reducing infections. Full-scale quarantine measures implemented on April 28 led to a significant improvement in onset-to-diagnosis time of all SARS patients, regardless of previous quarantine status. We discuss the temporal effects of quarantine measures and other interventions on detection and isolation as well as the potential usefulness of quarantine in faster identification of persons with SARS and in improving isolation measures.     

一起小学校内乙型流感暴发的调查

2004年9月下旬，浙江省江山市某乡镇中心小学发生了一起由乙型流感病毒引起流行性感冒暴发。经调查本次乙型流感共发现患者65例，罹患率15．26％。     

SARS transmission among hospital workers in Hong Kong

Despite infection control measures, breakthrough transmission of severe acute respiratory syndrome (SARS) occurred for many hospital workers in Hong Kong. We conducted a case-control study of 72 hospital workers with SARS and 144 matched controls. Inconsistent use of goggles, gowns, gloves, and caps was associated with a higher risk for SARS infection (unadjusted odds ratio 2.42 to 20.54, p < 0.05). The likelihood of SARS infection was strongly associated with the amount of personal protection equipment perceived to be inadequate, having <2 hours of infection control training, and not understanding infection control procedures. No significant differences existed between the case and control groups in the proportion of workers who performed high-risk procedures, reported minor protection equipment problems, or had social contact with SARS-infected persons. Perceived inadequacy of personal protection equipment supply, infection control training <2 hours, and inconsistent use of personal protection equipment when in contact with SARS patients were significant independent risk factors for SARS infection.