SARS transmission, risk factors, and prevention in Hong Kong.We analyzed an·a·lyze tr.v. an·a·lyzed, an·a·lyz·ing, an·a·lyz·es 1. To examine methodically by separating into parts and studying their interrelations. 2. Chemistry To make a chemical analysis of. 3. information obtained from 1,192 patients with probable severe acute respiratory syndrome Severe Acute Respiratory Syndrome (SARS) Definition Severe acute respiratory syndrome (SARS) is the first emergent and highly transmissible viral disease to appear during the twenty-first century. (SARS) reported in Hong Kong Hong Kong (hŏng kŏng), Mandarin Xianggang, special administrative region of China, formerly a British crown colony (2005 est. pop. 6,899,000), land area 422 sq mi (1,092 sq km), adjacent to Guangdong prov. . Among them, 26.6% were hospital workers, 16.1% were members of the same household as SARS patients and had probable secondary infections, 14.3% were Amoy Gardens Amoy Gardens (Chinese: 淘大花園; Jyutping: tou4 daai6 faa1 jyun4; Pinyin: táo dà huā yuán) is a high-density middle-class housing estate in Hong Kong completed from 1980 - 1987. residents, 4.9% were inpatients, and 9.9% were contacts of SARS patients who were not family members. The remaining 347 case-patients (29.1%) had undefined sources of infection. Excluding those [less than or equal to] 16 years of age, 330 patients with cases from "undefined" sources were used in a 1:2 matched case-control study case-control study, n an investigation employing an epidemiologic approach in which previously existing incidents of a medical condition are used in lieu of gathering new information from a randomized population. . Multivariate analysis multivariate analysis, n a statistical approach used to evaluate multiple variables. multivariate analysis, n a set of techniques used when variation in several variables has to be studied simultaneously. of this case-control study showed that having visited mainland China, hospitals, or the Amoy Gardens were risk factors (odds ratio [OR] 1.95 to 7.63). In addition, frequent mask use in public venues, frequent hand washing  This article or section contains .The purpose of Wikipedia is to present facts, not to teach subject matter. , and disinfecting the living quarters were significant protective factors (OR 0.36 to 0.58). In Hong Kong, therefore, community-acquired Community-acquired Refers to an infectious disease that is passed among individuals who have close contact with one another. Mentioned in: Mycoplasma Infections infection did not make up most transmissions, and public health measures have contributed substantially to the control of the SARS epidemic epidemic, outbreak of disease that affects a much greater number of people than is usual for the locality or that spreads to regions where it is ordinarily not present. . ********** As of June June: see month. 11, 2003, a total of 1,755 probable SARS cases were reported in Hong Kong (1). Some of the sources of SARS transmission are unknown. For instance, the first major SARS outbreak occurred in the Prince of Wales Hospital
ability of an agent to infect. and modes of transmission of the virus in the community setting. Also, reports that public health measures, such as wearing masks, frequent hand washing, avoidance of crowded places, disinfection disinfection, n the process of destroying pathogenic organisms or rendering them inert. disinfection, full oral cavity, n a procedure used to reduce active periodontal disease, usually completed within a certain short time frame. of the living quarters had been practiced by most of the Hong Kong population during the SARS outbreak (>90%) (5). The efficacy of widespread use of masks was controversial (6), and evaluating the efficacy of such measures in controlling the epidemic is important. Our study had two objectives. First, we sought to delineate the distribution of different sources of transmission of the SARS cases in Hong Kong. The number of cases with known and undefined sources was determined. Patients with known sources included those who were hospital workers, those who lived in the Amoy Gardens Estate, those who were probable secondary cases within a household (i.e., those with another household member who had SARS with an earlier date of onset), those who were inpatients and were cross-infected by other inpatients, and those persons who had contact with another SARS patient (who was not one of their household members) before the onset of lever lever, simple machine consisting of a bar supported at some stationary point along its length and used to overcome resistance at a second point by application of force at a third point. The stationary point of a lever is known as its fulcrum. . For the remaining cases, the virus was contracted through undefined sources. The second objective was to identify the undefined source group. A number of hypotheses were tested to identify relevant risk and protective factors associated with contracting the disease. Risk factors were related to visiting places of potentially high risk and meeting at-risk at-risk adj. Being endangered, as from exposure to disease or from a lack of parental or familial guidance and proper health care: efforts to make the vaccine available to at-risk groups of children. people. Preventive preventive /pre·ven·tive/ (pre-vent´iv) prophylactic. pre·ven·tive or pre·ven·ta·tive adj. Preventing or slowing the course of an illness or disease; prophylactic. n. factors were related to public health measures for prevention. Methods The study population comprised all probable SARS patients whose cases were reported to the Department of Health on or before May 16, 2003 (n = 1,690). The SARS case definition criteria, used by l-long Kong Hospital Authority, is as follows: radiographic radiographic (rā´dēōgraf´ik), adj relating to the process of radiography, the finished product, or its use. evidence of infiltrates Infiltrates Cells or body fluids that have passed into a tissue or body cavity. Mentioned in: Eosinophilic Pneumonia consistent with pneumonia pneumonia (n  mōn`yə), acute infection of one or both lungs that can be caused by a bacterium, usually Streptococcus pneumoniae and current temperature >38[degrees]C or a
history of such at any time in the preceding 2 days, and at least two of
the following: history of chills in the past 2 days, new or increased
cough cough, sudden, forceful expiration of air from the lungs caused by an involuntary contraction of the muscles controlling the process of breathing. The cough is a response to some irritating condition such as inflammation or the presence of mucus (sputum) in the , breathing difficulty, general malaise malaise /mal·aise/ (mal-az´) a vague feeling of discomfort. mal·aise n. A vague feeling of bodily discomfort, as at the beginning of an illness. or myalgia myalgia /my·al·gia/ (mi-al´jah) muscular pain.myal´gic epidemic myalgia see under pleurodynia. my·al·gia n. , typical signs of consolidation, and known exposure. These criteria for cases are equivalent to those in the World Health Organization's case definition for probable SARS cases (7). Data Collection Telephone numbers, as well as some demographic and clinical background information, for all probable SARS case-patients in Hong Kong (identified on or before May 16, 2003 [n = 1,690]) were obtained from the Department of Health. A team of trained interviewers called all these numbers, briefed the person answering the phone about the nature of the study, and invited their household to join the study. Informed consent was obtained directly from the respondents In the context of marketing research, a representative sample drawn from a larger population of people from whom information is collected and used to develop or confirm marketing strategy. . The number of SARS patients in the household was ascertained as·cer·tain tr.v. as·cer·tained, as·cer·tain·ing, as·cer·tains 1. To discover with certainty, as through examination or experimentation. See Synonyms at discover. 2. , and the interviewer identified the index patient, the person who had the earliest date of onset of fever if the household had more than one SARS patient. The rest of the SARS patients, those with later onset of illness, were considered as having probable secondary or tertiary tertiary (tûr`shēârē), in the Roman Catholic Church, member of a third order. The third orders are chiefly supplements of the friars—Franciscans (the most numerous), Dominicans, and Carmelites. cases. When a household had had two or more SARS patients with the same fever onset date (11 households), both were treated as index patients rather than as having probable secondary cases. The information obtained was cross-checked with that obtained from the SARS registry The configuration database in all 32-bit versions of Windows that contains settings for the hardware and software in the PC it is installed in. The Registry is made up of the SYSTEM.DAT and USER.DAT files. Many settings previously stored in the WIN.INI and SYSTEM. . Ethics approval was obtained from the Ethics Committee ethics committee A multidisciplinary hospital body composed of a broad spectrum of personnel–eg, physicians, nurses, social workers, priests, and others, which addresses the moral and ethical issues within the hospital. See DNR, Institutional review board. of the Chinese University of Hong Kong The motto of the university is "博文約禮" in Chinese, meaning "to broaden one's intellectual horizon and keep within the bounds of propriety". . The study was conducted from April 4, 2003, through June 10, 2003. Of the 1,690 probable SARS case-patients reported in Hong Kong as of May 16, a total of 1,214 (72%) SARS case-patients from 996 households were covered by our study. Of the remaining 476 case-patients not covered not covered Health care adjective Referring to a procedure, test or other health service to which a policy holder or insurance beneficiary is not entitled under the terms of the policy or payment system–eg, Medicare. Cf Covered. by this study, 140 case-patients (8.2%) did not have a correct telephone number, 163 (9.6%) could not be contacted after at least five attempts, 163 (9.6%) declined to participate, and 10 (0.6%) were either not in Hong Kong or could not communicate in Chinese or English. Study Design The study is part of a project that also includes an investigation of the secondary attack rate of household members. For the first part of this study, the index case-patients were asked whether they were hospital workers, inpatients before contracting SARS, or residents of the Amoy Gardens. The other respondents were asked whether onset of fever occurred within 10 days of contact with a SARS patient. These four types of SARS cases were classified into the known sources group. The rest of the index case-patients were classified into the undefined source group. In the second part of the study, a 1:2 matched case-control study was conducted for the undefined source group to identify risk and preventive factors associated with SARS transmission in the community setting. Adults [greater than or equal to] 16 years of age were included in the case-control study (17 case-patients were removed from the analysis). Potential geographically related risk factors studied included whether the case-patient had visited (but not lived in) Amoy Gardens, Prince of Wales Hospital, other hospitals or clinics, or crowded places within 10 days before onset of lever. Other risk factors were related to contact with other groups of people during the same reference period, including medical personnel, hospital visitors, and persons with influenzalike symptoms (who were not SARS case-patients). A number of protective factors were related to relevant public health measures, including the frequency of using a face mask Face mask The simplest way of delivering a high level of oxygen to patients with ARDS or other low-oxygen conditions. Mentioned in: Adult Respiratory Distress Syndrome in public venues, the frequency of washing hands each day, and disinfection of living quarters thoroughly during the same period. The same questions were asked to the control group, which was recruited by a random telephone survey. Members of the control group were matched for age and sex with the case-patient. The reference period was the same as that of the matched case-patient. Random telephone numbers were selected from up-to-date local telephone directories. Interviews were conducted in the evening to avoid over-representing those who were not working during the daytime Daytime may refer to:
. At least three calls were made before an unanswered call was considered as a noncontact. Informed consent was obtained before the interviews were conducted. Almost all case-patients were interviewed within 14 to 28 days after their onset of fever, and the control group was interviewed accordingly. When a participant was unable to answer the questionnaire, a proxy, who was most familiar with the family situation, was interviewed. Data Analyses For the case-control study, odds ratios (OR) were first examined by using univariate univariate adjective Determined, produced, or caused by only one variable logistic regression In statistics, logistic regression is a regression model for binomially distributed response/dependent variables. It is useful for modeling the probability of an event occurring as a function of other factors. models. The significant univariate variables were then entered as input for the multivariate The use of multiple variables in a forecasting model. forward conditional logistic regression analysis; p values <0.05 were statistically significant. SPSS A statistical package from SPSS, Inc., Chicago (www.spss.com) that runs on PCs, most mainframes and minis and is used extensively in marketing research. It provides over 50 statistical processes, including regression analysis, correlation and analysis of variance. for Windows Release 11.0.1 (SPSS Inc., Chicago, IL) was used to analyze the data. Results Cases with Known Sources of Transmission Of the 1,214 probable SARS cases covered by this study, 22 questionnaires (1.8%) were incomplete and did not allow us to classify clas·si·fy tr.v. clas·si·fied, clas·si·fy·ing, clas·si·fies 1. To arrange or organize according to class or category. 2. To designate (a document, for example) as confidential, secret, or top secret. the respondents into groups according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. source of transmission. The rest (n = 1,192) were analyzed. A total of 192 (16.1%) had probable cases of secondary or tertiary household transmission (Table 1) (i.e., another household member had SARS but fever onset occurred earlier). All the names All the Names (Portuguese: Todos os nomes) is a novel by Portuguese author José Saramago. It was written in 1997 and published in English in 2000 in an award winning translation by Margaret Jull Costa. were verified ver·i·fy tr.v. ver·i·fied, ver·i·fy·ing, ver·i·fies 1. To prove the truth of by presentation of evidence or testimony; substantiate. 2. as being reported to the SARS registry. Another 317 of 1,192 (26.6%) cases were hospital workers; 170 (14.3%) lived in the Amoy Gardens; 58 (4.9%) were inpatients who had been hospitalized for diseases other than SARS and kept on wards with SARS patients. Most infected in·fect tr.v. in·fect·ed, in·fect·ing, in·fects 1. To contaminate with a pathogenic microorganism or agent. 2. To communicate a pathogen or disease to. 3. To invade and produce infection in. inpatients were long-term Long-term Three or more years. In the context of accounting, more than 1 year. long-term 1. Of or relating to a gain or loss in the value of a security that has been held over a specific length of time. Compare short-term. chronic patients and bad been hospitalized for >2 weeks before having SARS symptoms. These patients were likely to have been cross-infected. A total of 727 case-patients belonged in one of the four categories (61% of 1,192 cases). Another 118 (9.9%) had come into contact with a SARS patient within a 10-day period before onset of fever. For 347 (29.1%) participants, the source was undefined; these participants were included in the case-control analysis. After excluding 17 case-patients [less than or equal to] 16 years of age, 330 participants were included in the case-control study. Univariate Case-Control Analysis Of the 330 patients with an undefined source of infection, 48% were men and 52% were women. The mean age of the patient group was 47.1 years for both the male and female case-patients (standard deviation In statistics, the average amount a number varies from the average number in a series of numbers. (statistics) standard deviation - (SD) A measure of the range of values in a set of numbers. [SD] 18.8 and 19.9, respectively, p > 0.05, t test). The percentage of participants in the undefined source group in the three periods of the epidemic (before March 25, 2003, from March 26 through April 10, and after April 10) were 24.2%, 36.1%, and 43.5%, respectively. Members of the patient group were more likely than the control group to have visited mainland China (12.7% vs. 6.5%, p < 0.005). One patient had visited Taiwan, another patient had visited Singapore, two controls had visited Taiwan, and none of the controls had visited Singapore (Singapore and Taiwan were listed as affected areas during the study period). Similarly, patients were also more likely than controls to have visited the Amoy Gardens (15% vs. 2%, OR = 9.10, p < 0.005) (keeping in mind that those who lived in the Amoy Gardens had already been removed from the analysis); patients were more likely than the controls to have visited the Prince of Wales Hospital (3.6% vs. 0.5%, OR = 8.27, p < 0.005) or other hospitals or clinics (40.7% vs. i7.0%, OR = 3.36, p < 0.005) (Table 2). A total of 212 cases of the undefined source group had visited at least one of the above-mentioned categories of places. Frequency of visiting crowded places was, however, not significant in the univariate analysis (21.91% vs. 20.8%, OR = 1.07, p > 0.05). Members of the case-patient and control groups were not statistically different in the percentage of having come into contact with someone with influenzalike symptoms (those having made contacts with SARS patients were already removed, 9.0% vs. 6.4%, OR = 1.42, p > 0.05). The two groups were also not different in the likelihood of having social contact with someone who had visited a hospital (8.2% vs. 5.2%, OR = 1.66, p > 0.05) or having social contact with medical personnel (7.6% vs. 8.6%, OR = 0.87, p > 0.05). Also patients were not more likely to have a known SARS patient living in the same housing estate, after Amoy Gardens patients had already been removed from the analysis (such data were made available to the public by the government after April 12, 2003) (8). Furthermore, matching for the reference period, members of the case group were less likely than members of the control group to have frequently worn a face mask in public venues (27.9% vs. 58.7%, OR 0.36, p < 0.005), to have been washed their hands >10 times a day (18.4% vs. 33.7% OR = 0.44, p < 0.005), and to have disinfected Disinfected Decreased the number of microorganisms on or in an object. Mentioned in: Isolation their living quarters thoroughly (46.6% vs. 74.5%, OR = 0.30, p < 0.005). Multivariate Analysis When all the variables that were significant in the univariate analysis were used as input for the multivariate stepwise stepwise incremental; additional information is added at each step. stepwise multiple regression used when a large number of possible explanatory variables are available and there is difficulty interpreting the partial regression conditional logistic regression analysis, the results show that among the 330 patients with undefined sources, the following were significant risk factors: having visited mainland China (OR = 1.95, p = 0.020, Table 2), having visited the Amoy Gardens (OR = 7.63, p < 0.001), having visited the Prince of Wales Hospital (OR - 7.07, p = 0.009), and having visited other hospitals or clinics (OR = 3.70, p < 0.001) during the reference period. On the other hand, using a mask frequently in public places (OR = 0.27, p < 0.001), washing one's hands >10 times a day (OR = 0.58, p = 0.008), and disinfecting the living quarters thoroughly (OR = 0.41, p < 0.001) during the reference period were significant protective factors (Table 2). Undefined Cases After removing those case-patients who may have contracted SARS after visiting the Amoy Gardens, the Prince of Wales Hospital, other hospitals, or an affected country, including mainland China, Singapore, and Taiwan (212 cases of the 330 cases), 118 cases remained undefined. They were likely to be community-acquired cases of unknown sources of transmission. When univariate and multivariate conditional logistic regression analyses were repeated for the 118 cases with undefined sources (after 212 patients who had visited some particular places that were associated with risk for transmission were removed from the analysis) and their controls (n = 236), similar results were obtained. The three public health variables--frequently wearing a mask in public places (adjusted OR = 0.36, p < 0.001), washing hands >10 times a day (adjusted OR = 0.44, p = 0.008), and disinfecting the living quarters thoroughly (adjusted OR = 0.36, p < 0.001) remained significant protective factors. Again, similar to the results of the previous analysis applied to the 330 cases, the other five variables (visiting crowded places, having contact with someone with influenzalike symptoms, having social contact with hospital visitors, having social contact with medical workers, and living with in the same housing estate as other SARS case-patients) were not significant risk factors. Discussion Of the 1,192 participants in this study, approximately 16.1% had probable secondary or tertiary transmission occurring within the household, 26.6% were hospital workers with nosocomial infections Nosocomial infections Infections that were not present before the patient came to a hospital, but were acquired by a patient while in the hospital. Mentioned in: Enterobacterial Infections, Staphylococcal Infections , 14.3% were Amoy Gardens patients, and 4.9% were cross-infected inpatients. In 9.9%, SARS might have been contracted when the participant came in contact with a SARS patient who was a nonhousehold member, which may have occurred in a hospital or community setting. SARS may have developed in 18.7% after they visited Amoy Gardens, hospitals or clinics, or affected countries. This computation Computation is a general term for any type of information processing that can be represented mathematically. This includes phenomena ranging from simple calculations to human thinking. leaves 9.9% as community-acquired cases of an unknown source. The percentage of patients related to Amoy Gardens (someone who lived there or visited there) is 18.8% (224/1,192). The percentage of patients with a hospital connection (hospital workers, inpatients, and visitors) is 44% (525/1,192). The proportion of unknown community-acquired SARS infection among all SARS cases in this study was considerably lower than the proportion of nosocomial infection Nosocomial infection An infection that can be acquired in a hospital. ABPA is a nosocomial infection. Mentioned in: Allergic Bronchopulmonary Aspergillosis, Hospital-Acquired Infections, Pseudomonas Infections , which suggests that preventing hospital outbreaks is essential. Of the 330 undefined transmissions, 44.2% of the transmissions occurred through hospital visitors. Another study on household transmission also indicated that hospital visits were a significant risk factor for predicting household secondary infection (9). Therefore, the severity of future outbreaks, if any, would depend on the ability of the hospital system to control hospital cross-infection cross-infection, n the transmission of a communicable disease from one person to another because of a poor barrier protection. and infection of visitors. Visits to mainland China were associated with SARS transmission, even after adjusting for other variables. Cross-border transmission played a role in the epidemic; although the absolute percentage is not high among the 1,192 case-patients (3.6% or 43/1,192), it is substantially larger among the undefined source group (12.4%). With a case-control design, we could not establish whether this 14.4% was associated with an inflated risk. Cross-border communication and prevention, such as those set in place (temperature screening and health declaration), need to be enforced strictly and consistently. Almost 70% of the 43 participants who visited mainland China had fever onset on or before April 1 (i.e., the early phase of the epidemic) (5). None of them had onset after May 3, which is understandable as visiting mainland China was perceived as a high risk by the general public in the late phase of the epidemic (5). The variables related to social contacts (with medical personnel or hospital visitors, with persons with influenzalike symptoms, and with persons living in a housing estate with a reported SARS patient) were not significant. These findings should be interpreted with caution. On one hand, these case-patients should not be stigmatized. On the other, the results may have been confounded because all SARS cases contracted this way were excluded from the analysis. However, confirming that these variables could not account for transmission of the undefined source cases can be useful. Evidence does not indicate that frequent visits to crowded places were associated with a higher likelihood of community-acquired infection. This finding may remove panic that arose during the epidemic, and daily life need not change as much as it had. Hong Kong is a densely populated pop·u·late tr.v. pop·u·lat·ed, pop·u·lat·ing, pop·u·lates 1. To supply with inhabitants, as by colonization; people. 2. city, and it had a large number of SARS cases. The number of community-acquired cases in less populated cities should be much lower than that of Hong Kong. This finding should be interpreted with care as >90% of the general public wore face masks in public places, and >85% avoided visits to public places during the epidemic in Hong Kong (5). Although visiting the Amoy Gardens was a risk factor, Amoy Gardens might be the only place where such a large-scale SARS outbreak was attributable to contamination of the environment. We now have some empirical evidence to suggest that wearing a face-mask frequently in public places, frequent handwashing handwashing, n a fundamental part of standard precaution procedures and disease control for dental personnel; helps reduce or prevent infection and transmittal of microbes among people and objects; for regular dental procedures, liquid soap and water is , and disinfecting one's living quarter were effective public health measures to reduce the risk for transmission (adjusted OR 0.58 to 0.36). The effectiveness of mask use was controversial (6). In another study, the prevalence of these three public health preventive public health measures increased significantly from March 21, 2003, to April 1,2003, (i.e., wearing masks 11.5%-84.3%; frequent hand washing 61.5%-95.1%; home disinfection 36.4%-80%) (5). These practices played an essential role in limiting the spread of the virus in the community in Hong Kong. That disinfecting the living quarter is a strong protective factor has a particular relevance. The reason behind the significance is not completely clear. During the epidemic, the Hong Kong government released frequent announcements of public interest to promote home disinfection using 1:99 bleach bleach Solid or liquid chemical compound used to whiten or remove the natural colour of fibres, yarns, paper, and textile fabrics. Sunlight was the chief bleaching agent up to the discovery of chlorine in 1774 by Karl Wilhelm Scheele (b. 1742—d. water solutions. Most respondents who disinfected their living quarters were probably following the government's suggestion. Keeping in mind that probable secondary cases had already been removed from the analysis, such protective effect is not referring to the effects that disinfecting the quarter reduced the chance of secondary infection. Environmental contamination (suspected to be related to the sewage system sewage system Collection of pipes and mains, treatment works, and discharge lines (sewers) for the wastewater of a community. Early civilizations often built drainage systems in urban areas to handle storm runoff. ) was reported in the Amoy Gardens, and similar environmental contamination probably did not occur in other places. Such contamination-related infections might be on a small scale and not been noticed. In such circumstances CIRCUMSTANCES, evidence. The particulars which accompany a fact. 2. The facts proved are either possible or impossible, ordinary and probable, or extraordinary and improbable, recent or ancient; they may have happened near us, or afar off; they are public or , home disinfection might reduce the risk for transmission. The finding suggests that, in addition to the droplet droplet very small drop of fluid. droplet nuclei the finite particles of matter which are transmitted from animal to animal. theory, the fomites fomites see fomes. theory could not be dismissed. Our study has a few limitations as well as strengths. First, approximately 72% of all SARS case-patients were included in the study (excluding patients whose contact numbers were incorrect or not available; approximately 78% of those with a valid contact telephone number were included, and the refusal rate was about 10%). The sample size was reasonably large. Second, data were collected retrospectively ret·ro·spec·tive adj. 1. Looking back on, contemplating, or directed to the past. 2. Looking or directed backward. 3. Applying to or influencing the past; retroactive. 4. . Most of the data were, however, collected from the participants within 1 month after onset of fever. Since contracting the disease is a major life event for the patient and family, they should be able to recall whether such factual and benchmark behaviors had been practiced. The study also has strength of matching for age, sex, and reference time of the behaviors in question, so that both the case and control in a pair were referring to relevant behaviors that occurred within the same 10-day period before the date of onset of fever of the patient. Third, stone questions, such as those about disinfection of households or visiting crowed places were nonspecific nonspecific /non·spe·cif·ic/ (non?spi-sif´ik) 1. not due to any single known cause. 2. not directed against a particular agent, but rather having a general effect. nonspecific 1. (the questions asked were "Whether your living quarter had been disinfected thoroughly" and "Whether you had visited crowded places"). Different participants might have defined the terms differently. Further, a number of patients were unable to answer the questions, and a household member who was "most familiar with the household situation" was invited to serve as a proxy. The responses obtained from these informants were compared to those obtained from the patients themselves, and no statistical significance was obtained (p 0.199 to 0.854) to all variables, except for the variable about visiting the Amoy Gardens (p < 0.05). One particular strength of the study in its evaluation of the three public health measures is that transmissions due to various known sources of infection had been removed as much as possible. In conclusion, the study shows that public health measures may have contributed substantially to the control of SARS epidemic in Hong Kong.
Table 1. Distribution of 1,214 severe acute respiratory
syndrome cases covered by the study (a)
n % (b)
Known sources 727 61.0
Probable secondary/tertiary 192 (d) 16.1
household infection
Hospital care workers 317 (d) 26.6
Amoy Gardens residents 170 (d) 14.3
Inpatients 58 (d) 4.9
Unknown sources
Contacted SARS patient(s) within 118 9.9
14 days before onset of fever (c)
Undefined sources 347 29.1
Visited Amoy Gardens 54 (d) 4.5
Visited PWH (e) 12 (d) 1.0
Visited other hospitals or clinics 142 (d) 11.9
Visited an affected country 45 (d) 3.8
None of the above 124 10.4
(a) Incomplete information for 22 cases;
complete information for 1,192 cases.
(b) Calculated based on complete data.
(c) These patients did not belong to the categories
listed under known sources.
(d) These categories are not mutually excluded, i.e., a
respondent may be exposed to more than one category.
(e) PWH, Prince of Wales Hospital.
Table 2. Preventive measures and risk factors reported
by cases and controls
Case Control
Factors (b) (c)
% visited mainland China 12.7 6.5
(reference=no)
% visited PWH (reference=no) 3.6 0.5
% visited other hospitals/clinics 40.7 17.0
(reference=no)
% visited Amoy Gardens (reference=no) 15.5 2.0
% visited crowded places frequently 21.9 20.8
(reference=occasionally/seldom/no)
% contacted someone with fever or 9.0 6.4
influenza (reference=no)
% social contact with someone who 8.2 5.2
visited a patient in a hospital
(reference=no)
% social contact with medical 7.6 8.6
personnel (reference=no)
% had a SARS case in the housing 6.6 8.5
estate (reference=no)
% disinfected the living quarters 46.6 74.5
thoroughly (reference=no)
Wore a mask in public places 27.9 58.7
frequently (reference=occasionally
/seldom/no)
Washed hands 11 or more times per day 18.4 33.7
(reference=1-10 times/day)
Matched univariate
Factors OR (95%, CI)
% visited mainland China 2.09 (1.33 to 3.27) (e)
(reference=no)
% visited PWH (reference=no) 8.27 (2.32 to 29.49) (e)
% visited other hospitals/clinics 3.36 (2.49 to 4.54)
(reference=no)
% visited Amoy Gardens (reference=no) 9.10 (4.87 to 17.00) (e)
% visited crowded places frequently 1.07 (11.76 to 1.50) NS
(reference=occasionally/seldom/no)
% contacted someone with fever or 1.42 (0.87 to 2.32) NS
influenza (reference=no)
% social contact with someone who 1.66 (0.96 to 2.85) NS
visited a patient in a hospital
(reference=no)
% social contact with medical 0.87 (0.52 to 1.44) NS
personnel (reference=no)
% had a SARS case in the housing 0.76 (0.44 to 1.31) NS
estate (reference=no)
% disinfected the living quarters 0.30 (0.23 to 0.39) (e)
thoroughly (reference=no)
Wore a mask in public places 0.27 (0.20 to 0.37) (e)
frequently (reference=occasionally
/seldom/no)
Washed hands 11 or more times per day 0.44 (0.31 to 0.63) (e)
(reference=1-10 times/day)
Matched multivariate p value
Factors OR (95% CI) (d)
% visited mainland China 1.95 (1.11 to 3.42) 0.020
(reference=no)
% visited PWH (reference=no) 7.07 (1.62 to 30.75) 0.009
% visited other hospitals/clinics 3.70 (2.54 to 5.39) <0.001
(reference=no)
% visited Amoy Gardens (reference=no) 7.63 (3.77 to 15.43) <0.001
% visited crowded places frequently -- --
(reference=occasionally/seldom/no)
% contacted someone with fever or -- --
influenza (reference=no)
% social contact with someone who -- --
visited a patient in a hospital
(reference=no)
% social contact with medical -- --
personnel (reference=no)
% had a SARS case in the housing -- --
estate (reference=no)
% disinfected the living quarters 0.41 (0.29 to 0.58) <0.001
thoroughly (reference=no)
Wore a mask in public places 0.36 (0.25 to 0.52) <0.001
frequently (reference=occasionally
/seldom/no)
Washed hands 11 or more times per day 0.58 (0.38 to 0.87) 0.008
(reference=1-10 times/day)
(a) N.S., not significant; OR, odds ratio; CI, confidence
interval; PWH, Prince of Wales Hospital; --, not used by
the multivariate analyses. The reference time period was
the 10 days before the date of the patient's onset of fever.
(b) n = 330.
(c) n = 660.
(d) p values for multivariate OR.
(e) p < 0.005.
This study was solely funded by the Chinese University of Hong Kong. References (1.) World Health Organization. Cumulative number of reported probable cases of SARS. [cited 2003 July 11]; Available from: http://www.who.int/csr/sars/country/2003_07_09/en/ (2.) Lee N, Hui D, Wu A, Chan P, Cameron P, Joynt GM, et al. A major outbreak of severe acute respiratory syndrome in Hong Kong. N Engl J Med 2003;348:1986-44. (3.) Health, Welfare and Food Bureau The Health, Welfare and Food Bureau (Traditional Chinese: 衞生福利及食物局) of Hong Kong oversees the policies on health, welfare, environmental hygiene and food issues. . Health, Welfare and Food Bureau SARS Bulletin (18 April 2003). [cited 2003 July 11] ; Available from: http://www.info.gov.hk/dh/diseases/ap/eng/bulletin0418.htm (4.) Government Information Centre of Hong Kong. Situation report on severe acute respiratory syndrome. [cited 2003 July 11]; Available from: http://www.info.gov.hk/dh/new/bulletin/bullet.htm (5.) Lau JT, Yang yang (yang) [Chinese] in Chinese philosophy, the active, positive, masculine principle that is complementary to yin; see yin, under principle. X, Tsui H, Kim JH. Monitoring community responses to the SARS epidemic in Hong Kong: from day 10 to day 62. J Epidemiol Community Health 2003;57:864-70. (6.) Hong Kong Department of Health. Wearing mask. [cited 2003 July 14]; Available from: http://www.info.gov.hk/dh/diseases/ap/eng/facemask.htm (7.) Hong Kong Hospital Authority. Diagnosis and reporting. [cited 2003 July 11]; Available from: http://www.ha.org.hk/sars/ps/information/diagnosis_n_report.htm (8.) Hong Kong Department of Health. List of buildings with SARS cases released. [cited 2003 July 15]; Available from: http://www.info.gov.hk/dh/new/2003/03-04-12e2.htm (9.) Lau JTF JTF Joint Task Force JTF Just the Facts JTF Jewish Task Force JTF Jitter Transfer Function JTF Joint Tactical Force JTF Joint Tactical Fusion JTF Janasaviya Trust Fund (Sri Lanka) JTF Joint Test Facility , Lau M, Kim JH, Wong E, Tsui H-Y, Tsang T, et al. Probable secondary infections in households of SARS patients in Hong Kong. Emerg Infect infect /in·fect/ (in-fekt´) 1. to invade and produce infection in. 2. to transmit a pathogen or disease to. in·fect v. 1. Dis [serial online] 2004 Feb [Feb 11, 2004]. Available from: http://www.cdc.gov/ncidod/EID/vol10no2/03-0626.htm Dr. Lau is the director of the Center for Epidemiology epidemiology, field of medicine concerned with the study of epidemics, outbreaks of disease that affect large numbers of people. Epidemiologists, using sophisticated statistical analyses, field investigations, and complex laboratory techniques, investigate the cause and Biostatistics biostatistics /bio·sta·tis·tics/ (-stah-tis´tiks) biometry. bi·o·sta·tis·tics n. The science of statistics applied to the analysis of biological or medical data. of the School of Public Health of the Chinese University of Hong Kong. His research interests include community research on behavioral behavioral pertaining to behavior. behavioral disorders see vice. behavioral seizure see psychomotor seizure. aspects of infectious disease Infectious disease A pathological condition spread among biological species. Infectious diseases, although varied in their effects, are always associated with viruses, bacteria, fungi, protozoa, multicellular parasites and aberrant proteins known as prions. , such as HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States. prevention studies. Address for correspondence: Joseph T.F. Lau, Centre for Epidemiology and Biostatistics, 5/F, School of Public Health. Prince of Wales Hospital, Shatin, N.J., Hong Kong; fax: 852-2645-3098; email: jlau@cuhk.edu.hk Joseph T.F. Lau, * Hiyi Tsui, * Mason Lau, * and Xilin Yang * * Chinese University of Hong Kong, Hong Kong, China |
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