Lack of SARS transmission and U.S. SARS case-patient

In early April 2003, severe acute respiratory syndrome (SARS) was diagnosed in a Pennsylvania resident after his exposure to persons with SARS in Toronto, Canada. To identify contacts of the case-patient and evaluate the risk for SARS transmission, a detailed epidemiologic investigation was performed. On the basis of this investigation, 26 persons (17 healthcare workers, 4 household contacts, and 5 others) were identified as having had close contact with this case-patient before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-associated coronavirus (SARS-CoV) infection to any close contact of this patient. This investigation documents that, under certain circumstances, SARS-CoV is not readily transmitted to close contacts, despite ample unprotected exposures. Improving the understanding of risk factors for transmission will help focus public health control measures.     

Epidemiologic Findings from Case Investigations and Contact Tracing for First 200 Cases of Coronavirus Disease,Santa Clara County,California, USA

In January 2020, Santa Clara County, California, USA, began identifying laboratory-confirmed coronavirus disease among residents. County staff conducted case and contact investigations focused on households and collected detailed case demographic, occupation, exposure, and outcome information. We describe the first 200 test-positive cases during January 31–March 20, 2020, to inform future case and contact investigations. Probable infection sources included community transmission (104 cases), known close contact with a confirmed case-patient (66 cases), and travel (30 cases). Disease patterns across race and ethnicity, occupational, and household factors suggested multiple infection risk factors. Disproportionately high percentages of case-patients from racial and ethnic subgroups worked outside the home (Hispanic [86%] and Filipino [100%]); household transmission was more common among persons from Vietnam (53%). Even with the few initial cases, detailed case and contact investigations of household contacts capturing occupational and disaggregated race and ethnicity data helped identify at-risk groups and focused solutions for disease control.     

福建省新型冠状病毒肺炎患者密切接触者的流行病学特征与感染危险因素

  目的   探讨新型冠状病毒肺炎(coronavirus disease 2019, COVID-19)患者的密切接触者的流行病学特征和感染的危险因素。   方法   描述2020年福建省111名COVID-19患者的密切接触者特征, 以111名(102名确诊和9名无症状感染者)感染新型冠状病毒的密切接触者为病例组, 以未感染新型冠状病毒且资料完整的2 337名密切接触者为对照组, 采用Logistic回归分析模型探讨密切接触者感染的危险因素。   结果   111例中男性57名, 女性54名, 男女比为1.1:1, 年龄中位数为49.5岁, 密切接触者感染率为1.7%(111/6 718)。引起47起聚集性疫情, 占总起数88.7%(47/53), 占总病例数54.7%(162/296), 有7例潜伏期超过14 d, 最长达21 d, 1起聚集性疫情显示原代病例发病前2 d具有感染性。家庭续发率4.2%(73/1 739)、社区续发率为10.1%(24/237)、养老院续发率2.7%(7/256)、社交场所续发率为2.0%(4/199)、工作场所续发率3.0%(3/99), 续发率差异有统计学意义(χ2=20.76, P < 0.001)。确诊病例以轻型和普通型为主(88.2%), 临床严重程度与原代病例没有区别。最后接触到确定密切接触者时间中位数为2 d, 确定密切接触者到实施隔离时间为中位数1 d, 最后接触到发病时间中位数为7 d, 发病至就诊时间中位数为4.9 d, 就诊到确诊均在当天完成。多因素分析结果显示, 随着年龄的增大, 感染风险越大, 15~岁(OR=4.22, 95% CI:1.79~9. 96)和≥50岁(OR=6.61, 95% CI:2.77~15.78);接触频率时间越久, 受感染的机会越大, 一般接触(OR=3.58, 95% CI:1.70~7.54)和经常接触(OR=8.30, 95% CI:4.65~14.80);暴露于现症病例(OR=3.64, 95% CI:1.65~8.04)更易感染。   结论   新型冠状病毒续发率较高, 在2.0%以上; 感染新型冠状病毒的密切接触者临床严重程度与原代病例没有差别, 均以轻症为主, 年龄、接触频率和原代病例有无症状是其危险因素; 密切接触者协同追踪管理信息化程度不高, 成效不理想。     

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。     

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.     

Influence of meteorological factors and air pollution on the outbreak of severe acute respiratory syndrome

OBJECTIVES: To understand the association between the outbreak of severe acute respiratory syndrome (SARS) and meteorological factors and air pollution. STUDY DESIGN: An ecological study was conducted. METHODS: Three hundred and fifty primary probable SARS cases diagnosed in mainland China between 1 January and 31 May 2003, and their 6727 close contacts during the period of their clinical symptoms before admission, were included in this study. Of the 6727 close contacts, 135 (2.0%) later developed clinical symptoms and were diagnosed as probable SARS cases. The daily meteorological data and daily air pollution data during the same SARS outbreak period in mainland China were used in the data analysis. Logistic regression analyses were conducted to explore the association between the secondary attack rate of SARS and meteorological factors and air pollution. RESULTS: In univariate analyses, daily average temperature (DAT), daily average air pressure (DAAP), and daily average relative humidity (DARH) were inversely associated with secondary attack rate (P<0.001); a significant positive association was found for daily hours of sunshine (DHS) (P<0.001). In multivariate analyses, factors associated with secondary attack rate were DAAP (odds ratio (OR)=0.53, 95% confidence interval (CI): 0.42, 0.66), DARH (OR=0.73, 95% CI: 0.53, 1.00), and daily average wind velocity (DAWV; OR=0.81, 95% CI: 0.68, 0.96). Adjustment for the onset time of a primary case led to little change in the results. In addition, in Hebei Province, a major affected area in China, only DAWV (OR=0.38, 95% CI: 0.20, 0.72) was a significant predictor of secondary attack rate with adjustment for the onset time of primary case. In Inner Mongolia, another major affected area in China, DAWV (OR=0.50, 95% CI: 0.26, 0.94) and DHS (OR=0.27, 95% CI: 0.09, 0.81) were significant predictors of secondary attack rate with adjustment for the onset time of primary case. CONCLUSIONS: Our results suggest that the SARS outbreak was significantly associated with DAWV, and that DAAP, DARH and DHS may also have influenced the SARS outbreak to some extent. However, because of ecological fallacy and uncontrolled confounding effects that may have biased the results, the association between the SARS outbreak and these meteorological factors and air pollution deserve further investigation.     

基于广州市聚集性疫情的新型冠状病毒传染力及续发率研究

目的 基于广州市新型冠状病毒肺炎（COVID-19）聚集性疫情,分析新型冠状病毒的传染力和续发率,为COVID-19疫情防控的策略提供参考依据。方法 对广州市COVID-19（确诊病例和无症状感染者）区分输入病例和本地病例,选择聚集性疫情首发病例为指示病例,以最短潜伏期1~3 d分别评估传染力和续发率。结果 截至2020年2月18日,广州市共报告新型冠状病毒感染病例349例,其中,确诊病例339例（占97.13%）,无症状感染者10例（占2.87%）。共报告聚集性疫情68起,涉及新型冠状病毒感染病例217例（确诊病例210例,无症状感染者7例）。每起聚集性疫情的新型冠状病毒感染例数中位数为3例,确诊病例数中位数为2例,无症状感染者数中位数为1例。最短潜伏期1~3 d的传染力平均值为2.18（即每起聚集性疫情中每个病例平均传染2.18人）,家庭成员传染力平均值为1.86,家庭成员传染力比例为85.32%（1.86/2.18）。最短潜伏期为1~3 d的全部密切接触者续发率为17.12%~18.99%,其中,家庭成员续发率为46.11%~49.56%。结论 广州市COVID-19聚集性疫情以家庭聚集性为主,传染力强,加强防控措施可有效控制社区传播。     

上海市传染性非典型肺炎流行病学特征分析

[目的 ]　分析上海市 2 0 0 3年传染性非典型肺炎 (SARS)流行病学特征 ,初步评价防制效果。　 [方法 ]　采用统一的流行病学调查表对病例进行流行病学调查 ,描述和分析流行病学、病原学等相关资料和控制措施。　 [结果 ]　2 0 0 3年 3月下旬至 5月上旬 ,19个区县有 5个区报告SARS病例共 8例 ,发病率为 0 .0 5 / 10万 ,其中 5例由疑似转为临床病人 ,发病主要集中在 4月份 ,均为 2 0岁以上成年人。除 1例为接触感染 ,其余 7例均为非本地感染病人。经治疗 6例治愈出院 ,2例死亡 (为 60岁以上者 )。病人密切接触者 3 3 3人中发生 1例病人 ,续发病率为 0 .3 %。医务人员中无一人感染 ,家庭和社区内未发生集聚性发病。　 [结论 ]　上海市SARS病人以非本地感染为主 ,续发病率低 ,采取及时有效地隔离病人 ,对密切接触者医学观察和采取个人防护措施 ,是切断传播链的有效途径     

天津市传染性非典型肺炎流行特点及主要控制措施效果评价

目的：分析天津市传染性非典型肺炎[严重急性呼吸综合征(SARS)]流行病学特征，对主要控制措施的效果进行初步评价。方法：采用自行设计的病例报告表，全市统一的流行病学个案调查表及病例接触者、密切接触者树状分布图，深入病房、家庭、社区、团体等对病例及接触者进行调查。结果：以发病时间计算，自2003年4月13日至5月8日，包括输入病例在内发病175例，发病率为1．9／10万，其中死亡14例，病死率达8．O％。整个流行过程不足1个月，流行特点：1例“超级传播者”直接或间接传染了全市94．3％的病例；呈现以A、B、C 3家医院聚集发病为特点的爆发性流行，占全市病例的68．6％，3家医院外的家庭聚集发病占全市病例的14．3％，同事间传播为2．3％，散发者为9．1％，这些散发者未造成接触者感染；早期医务人员发病较多，占总病例数的38．2％，流行全过程参加SARS救治工作的1975名医护人员的总感染率为3．4％；全部流行过程传染源明确，传染链清晰，全市仅3例患者未找到传染源，占病例总数的2％；在10例源头病例中仅“超级传播者”和另一病例传染了其接触者，其他传染源由于及时隔离未造成任何传播。结论：SARS是严重急性呼吸系统传染病，如能及时准确地掌握传染链并进行范围适当、及时有效的封闭及隔离措施，以科学的方法提高全民的警觉度，传染链可能在较短时间内被切断，从而控制传播。     

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。     

SARS-CoV-2 infection risk among vaccinated and unvaccinated household members during the Alpha variant surge – Denver,Colorado, and San Diego,California, January–April 2021

BackgroundCOVID-19 vaccination reduces SARS-CoV-2 infection and transmission. However, evidence is emerging on the degree of protection across variants and in high-transmission settings. To better understand the protection afforded by vaccination specifically in a high-transmission setting, we examined household transmission of SARS-CoV-2 during a period of high community incidence with predominant SARS-CoV-2 B.1.1.7 (Alpha) variant, among vaccinated and unvaccinated contacts.MethodsWe conducted a household transmission investigation in San Diego County, California, and Denver, Colorado, during January-April 2021. Households were enrolled if they had at least one person with documented SARS-CoV-2 infection. We collected nasopharyngeal swabs, blood, demographic information, and vaccination history from all consenting household members. We compared infection risks (IRs), RT-PCR cycle threshold values, SARS-CoV-2 culture results, and antibody statuses among vaccinated and unvaccinated household contacts.ResultsWe enrolled 493 individuals from 138 households. The SARS-CoV-2 variant was identified from 121/138 households (88%). The most common variants were Alpha (75/121, 62%) and Epsilon (19/121, 16%). There were no households with discordant lineages among household members. One fully vaccinated secondary case was symptomatic (13%); the other 5 were asymptomatic (87%). Among unvaccinated secondary cases, 105/108 (97%) were symptomatic. Among 127 households with a single primary case, the IR for household contacts was 45% (146/322; 95% Confidence Interval [CI] 40–51%). The observed IR was higher in unvaccinated (130/257, 49%, 95% CI 45–57%) than fully vaccinated contacts (6/26, 23%, 95% CI 11–42%). A lower proportion of households with a fully vaccinated primary case had secondary cases (1/5, 20%) than households with an unvaccinated primary case (66/108, 62%).ConclusionsAlthough SARS-CoV-2 infections in vaccinated household contacts were reported in this high transmission setting, full vaccination protected against SARS-CoV-2 infection. These findings further support the protective effect of COVID-19 vaccination and highlight the need for ongoing vaccination among eligible persons.     

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。     

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.     

Duration and distance of exposure are important predictors of transmission among community contacts of Ontario SARS cases

We report attack rates and contact-related predictors among community contacts of severe acute respiratory syndrome (SARS) cases from the 2003 Toronto-area outbreak. Community contact data was extracted from public health records for single, well-defined exposures to a SARS case. In total, 8662 community-acquired exposures resulted in 61 probable cases; a crude attack rate of 0.70% [95% confidence interval (CI) 0.54-0.90]. Persons aged 55-69 years were at higher risk of acquiring SARS (1.14%) than those either younger (0.60%) or older (0.70%). In multivariable analysis exposures for at least 30 min at a distance of 相似文献   

Estimating the role of casual contact from the community in transmission of Bordetella pertussis to young infants

The proportion of infant pertussis cases due to transmission from fcasual contact in the community has not been estimated since before the introduction of pertussis vaccines in the 1950s. This study aimed to estimate the proportion of pertussis transmission due to casual contact using demographic and clinical data from a study of 95 infant pertussis cases and their close contacts enrolled at 14 hospitals in France, Germany, Canada, and the U.S. between February 2003 and September 2004. A complete case analysis was conducted as well as multiple imputation (MI) to account for missing data for participants and close contacts who did not participate. By considering all possible close contacts, the MI analysis estimated 66% of source cases were close contacts, implying the minimum attributable proportion of infant cases due to transmission from casual contact with community members was 34% (95% CI = 24%, 44%). Estimates from the complete case analysis were comparable but less precise. Results were sensitive to changes in the operational definition of a source case, which broadened the range of MI point estimates of transmission from casual community contact to 20%–47%. We conclude that casual contact appears to be responsible for a substantial proportion of pertussis transmission to young infants.     

上海市宝山区新型冠状病毒肺炎病例密切接触者感染危险因素分析

目的 探讨上海市宝山区新型冠状病毒肺炎病例密切接触者感染的危险因素,以期对后续的预防与控制提供依据。 方法 根据宝山区疾病预防控制中心现场流行病学调查和医学观察得到的疫情和密切接触者资料,通过单因素分析及二分类logistic回归模型多因素分析的方法,得出密接接触者感染的风险因素。 结果 2020年1月19日—5月31日,宝山区共管理确诊病例密切接触者885例,最终19例确诊为新型冠状病毒肺炎,感染率为2.15%。不同年龄组的密切接触者感染率差异有统计学意义(χ²=22.231,P＜0.001);与病例关系不同的密切接触者感染率差异有统计学意义(P＜0.001);与病例接触频率不同的密切接触者感染率差异有统计学意义(Fisher精确检验,P＜0.001);与病例接触地点不同的密切接触者感染率差异有统计学意义(Fisher精确检验,P＜0.001);与病例接触方式不同的密切接触者感染率差异有统计学意义(χ²=118.825,P＜0.001)。二分类logistic回归模型多因素分析显示:密切接触者与关联病例的接触方式为共同生活(OR=74.302,95%CI:16.694~330.697)、年龄增加(OR=2.112,95%CI:1.039~4.294)为其感染的危险因素。 结论 新冠肺炎病例的密切接触者管理过程中,与病例共同居住生活的、年龄高于60岁的密切接触者,为感染高危风险人群,需要重点防控。     

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％。     

Transmission routes of influenza A(H1N1)pdm09: analyses of inflight outbreaks

Knowledge about the infection transmission routes is significant for developing effective intervention strategies. We searched the PubMed databases and identified 10 studies with 14 possible inflight influenza A(H1N1)pdm09 outbreaks. Considering the different mechanisms of the large-droplet and airborne routes, a meta-analysis of the outbreak data was carried out to study the difference in attack rates for passengers within and beyond two rows of the index case(s). We also explored the relationship between the attack rates and the flight duration and/or total infectivity of the index case(s). The risk ratios for passengers seated within and beyond the two rows of the index cases were 1.7 (95% confidence interval (CI) 0.98–2.84) for syndromic secondary cases and 4.3 (95% CI 1.25–14.54) for laboratory-confirmed secondary cases. Furthermore, with an increase of the product of the flight duration and the total infectivity of the index cases, the overall attack rate increased linearly. The study indicates that influenza A(H1N1)pdm09 may mainly be transmitted via the airborne route during air travel. A standardised approach for the reporting of such inflight outbreak investigations would help to provide more convincing evidence for such inflight transmission events.Key words: Airborne route, inflight outbreaks, influenza, meta-analysis     

An outbreak of Salmonella hadar associated with food consumption at a building site canteen

A biphasic outbreak of gastroenteritis caused by Salmonella hadar affected canteen employees and workers at a construction site in central Italy in September 1994. There were 448 symptomatic cases, from 61 of whom group C Salmonella was isolated. Six cases were canteen employees. Twenty-two other individuals were asymptomatic excreters. There were 10 secondary cases. Working as a food handler at the canteen constituted an increased risk of infection, independently of ingestion of the food (odds ratio: 62.1; 95% confidence interval (CI): 9.5– 406.6). Having eaten at the canteen on the 19th and 20th September was identified as risk factor for subjects symptomatic within 72 hours (relative risk (RR): 17.0, 95% CI: 2.3–124.3), and cooled meat salad was identified as the vehicle of infection (RR: 36.6, 95% CI: 14.3–93.8). The use of portable toilets was another possible route of transmission of infection for all cases (RR: 1.3, 95% CI: 1.0–1.6). The index case was a cook who had symptoms five days before the peak of the outbreak. From 27 individuals both symptomatic and asymptomatic excreters group B, group D and not-typed Salmonellas were isolated. This study underlines the problem of improper food handling in salmonellosis outbreaks and emphasizes the role of several vehicles in the transmission of salmonellosis in a community.     

一起院内传染性非典型肺炎感染的传播链分析

目的：调查一起严重急性呼吸综合征(SARS)院内感染的传播过程，分析造成院内感染的原因和流行病学特点，为预防和控制院内SARS感染提供可借鉴的资料。方法：采用统一的流行病学调查表，通过座谈了解，查看病案和感染现场调查相结合进行追踪和个案调查。绘制传播链说明本次院内感染的传播过程，描述发病时间分布、接触史和接触方式。结果：传染源为1名输入性病例，与该案例传播相关接触者54人，发病5人，总罹患率为9．26％。其中指征病例传播了1例和这名二代病例又传播了4例续发病例，其传播过程可以用清晰的传播链加以描述；此5例病例均与前代病例的症状期有密切接触史，发病潜伏期长，潜伏期平均10d以上；后对在症状期所有接触者进行隔离，无发病。结论：本案例中所有续发病例都有与症状期病例明确的近距离密切接触史，但密切接触者并非全部发病；病原体传播与环境条件有关；急诊科护士是SARS感染高危人群；院内SARS感染可防可制。