133 results on '"Tsang, Tim K."'
Search Results
102. Association Between the Respiratory Microbiome and Susceptibility to Influenza Virus Infection.
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Tsang, Tim K, Lee, Kyu Han, Foxman, Betsy, Balmaseda, Angel, Gresh, Lionel, Sanchez, Nery, Ojeda, Sergio, Lopez, Roger, Yang, Yang, Kuan, Guillermina, and Gordon, Aubree
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INFLUENZA transmission , *BACTERIOLOGY technique , *HUMAN microbiota , *INFLUENZA , *LONGITUDINAL method , *NOSE , *PHARYNX , *RISK assessment , *STREPTOCOCCUS , *HOME environment , *INFLUENZA A virus , *INFLUENZA B virus , *DESCRIPTIVE statistics , *GRAM-negative anaerobic bacteria , *MIXED infections , *DISEASE risk factors - Abstract
Background Previous studies suggest that the nose/throat microbiome may play an important role in shaping host immunity and modifying the risk of respiratory infection. Our aim is to quantify the association between the nose/throat microbiome and susceptibility to influenza virus infection. Methods In this household transmission study, index cases with confirmed influenza virus infection and their household contacts were followed for 9–12 days to identify secondary influenza infections. Respiratory swabs were collected at enrollment to identify and quantify bacterial species via high-performance sequencing. Data were analyzed by an individual hazard-based transmission model that was adjusted for age, vaccination, and household size. Results We recruited 115 index cases with influenza A(H3N2) or B infection and 436 household contacts. We estimated that a 10-fold increase in the abundance in Streptococcus spp. and Prevotella salivae was associated with 48% (95% credible interval [CrI], 9–69%) and 25% (95% CrI, 0.5–42%) lower susceptibility to influenza A(H3N2) infection, respectively. In contrast, for influenza B infection, a 10-fold increase in the abundance in Streptococcus vestibularis and Prevotella spp. was associated with 63% (95% CrI, 17–83%) lower and 83% (95% CrI, 15–210%) higher susceptibility, respectively. Conclusions Susceptibility to influenza infection is associated with the nose/throat microbiome at the time of exposure. The effects of oligotypes on susceptibility differ between influenza A(H3N2) and B viruses. Our results suggest that microbiome may be a useful predictor of susceptibility, with the implication that microbiome could be modulated to reduce influenza infection risk, should these associations be causal. [ABSTRACT FROM AUTHOR]
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- 2020
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103. Assessment of Human-to-Human Transmissibility of Avian Influenza A(H7N9) Virus Across 5 Waves by Analyzing Clusters of Case Patients in Mainland China, 2013–2017
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Wang, Xiling, primary, Wu, Peng, additional, Pei, Yao, additional, Tsang, Tim K, additional, Gu, Dantong, additional, Wang, Wei, additional, Zhang, Juanjuan, additional, Horby, Peter W, additional, Uyeki, Timothy M, additional, Cowling, Benjamin J, additional, and Yu, Hongjie, additional
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- 2018
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104. Evaluation of animal-to-human and human-to-human transmission of influenza A (H7N9) virus in China, 2013–15
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Virlogeux, Victor, primary, Feng, Luzhao, additional, Tsang, Tim K., additional, Jiang, Hui, additional, Fang, Vicky J., additional, Qin, Ying, additional, Wu, Peng, additional, Wang, Xiling, additional, Zheng, Jiandong, additional, Lau, Eric H. Y., additional, Peng, Zhibin, additional, Yang, Juan, additional, Cowling, Benjamin J., additional, and Yu, Hongjie, additional
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- 2018
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105. Risk for International Importations of Variant SARS-CoV-2 Originating in the United Kingdom.
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Zhanwei Du, Lin Wang, Bingyi Yang, Ali, Sheikh Taslim, Tsang, Tim K., Songwei Shan, Peng Wu, Lau, Eric H. Y., Cowling, Benjamin J., Meyers, Lauren Ancel, Du, Zhanwei, Wang, Lin, Yang, Bingyi, Shan, Songwei, and Wu, Peng
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SARS-CoV-2 - Abstract
A fast-spreading severe acute respiratory syndrome coronavirus 2 variant identified in the United Kingdom in December 2020 has raised international alarm. We analyzed data from 15 countries and estimated that the chance that this variant was imported into these countries by travelers from the United Kingdom by December 7 is >50%. [ABSTRACT FROM AUTHOR]
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- 2021
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106. Assessment of Human-to-Human Transmissibility of Avian Influenza A(H7N9) Virus Across 5 Waves by Analyzing Clusters of Case Patients in Mainland China, 2013–2017.
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Wang, Xiling, Wu, Peng, Pei, Yao, Tsang, Tim K, Gu, Dantong, Wang, Wei, Zhang, Juanjuan, Horby, Peter W, Uyeki, Timothy M, Cowling, Benjamin J, and Yu, Hongjie
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INFLUENZA epidemiology ,CHI-squared test ,CONFIDENCE intervals ,RELATIVE medical risk ,DIAGNOSIS ,INFECTIOUS disease transmission ,DISEASE risk factors - Abstract
Background The 2016–17 epidemic of human infections with avian influenza A(H7N9) virus was alarming, due to the surge in reported cases across a wide geographic area and the emergence of highly-pathogenic A(H7N9) viruses. Our study aimed to assess whether the human-to-human transmission risk of A(H7N9) virus has changed across the 5 waves since 2013. Methods Data on human cases and clusters of A(H7N9) virus infection were collected from the World Health Organization, open access national and provincial reports, informal online sources, and published literature. We compared the epidemiological characteristics of sporadic and cluster cases, estimated the relative risk (RR) of infection in blood relatives and non–blood relatives, and estimated the bounds on the effective reproductive number (R
e ) across waves from 2013 through September 2017. Results We identified 40 human clusters of A(H7N9) virus infection, with a median cluster size of 2 (range 2–3). The overall RR of infection in blood relatives versus non–blood relatives was 1.65 (95% confidence interval [CI]: 0.88, 3.09), and was not significantly different across waves (χ2 = 2.66, P =.617). The upper limit of Re for A(H7N9) virus was 0.12 (95% CI: 0.10, 0.14) and was not significantly different across waves (χ2 = 1.52, P =.822). Conclusions The small cluster size and low Re suggest that human-to-human transmissibility of A(H7N9) virus has not changed over time and remains limited to date. Continuous assessment of A(H7N9) virus infections and human case clusters is of crucial importance for public health. [ABSTRACT FROM AUTHOR]- Published
- 2019
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107. Individual Correlates of Infectivity of Influenza A Virus Infections in Households
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Tsang, Tim K., primary, Fang, Vicky J., additional, Chan, Kwok-Hung, additional, Ip, Dennis K. M., additional, Leung, Gabriel M., additional, Peiris, J. S. Malik, additional, Cowling, Benjamin J., additional, and Cauchemez, Simon, additional
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- 2016
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108. Association between the Severity of Influenza A(H7N9) Virus Infections and Length of the Incubation Period
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Virlogeux, Victor, primary, Yang, Juan, additional, Fang, Vicky J., additional, Feng, Luzhao, additional, Tsang, Tim K., additional, Jiang, Hui, additional, Wu, Peng, additional, Zheng, Jiandong, additional, Lau, Eric H. Y., additional, Qin, Ying, additional, Peng, Zhibin, additional, Peiris, J. S. Malik, additional, Yu, Hongjie, additional, and Cowling, Benjamin J., additional
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- 2016
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109. Transmissibility of Norovirus in Urban Versus Rural Households in a Large Community Outbreak in China.
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Tim K. Tsang, Tian-Mu Chen, Longini Jr, Ira M., Halloran, M. Elizabeth, Ying Wu, Yang Yang, Tsang, Tim K, Chen, Tian-Mu, Longini, Ira M Jr, Wu, Ying, and Yang, Yang
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Background: Norovirus is a leading cause of outbreaks of acute infectious gastroenteritis worldwide, yet its transmissibility within households and associated risk factors remain unknown in developing countries.Methods: Household, demographic, and clinical data were collected from a semi-urban area in south China where an outbreak occurred in the winter of 2014. Using a Bayesian modeling framework, we assessed the transmissibility and potential risk modifiers in both urban and rural households.Results: In urban apartment buildings, the secondary attack rates were 84% (95% credible interval [CI] = 60%, 96%) among households of size two and 29% (95% CI = 9.6%, 53%) in larger households. In the rural village, secondary attack rate estimates were lower than the urban setting, 13% (0.51%, 54%) for households of size two and 7.3% (0.38%, 27%) for larger households. Males were 31% (95% CI = 3%, 50%) less susceptible to the disease than female. Water disinfection with chlorine was estimated to reduce environmental risk of infection by 60% (95% CI = 26%, 82%), and case isolation was estimated to reduce person-to-person transmission by 65% (95% CI = 15%, 93%). Nausea and vomiting were not associated with household transmission.Conclusions: Norovirus is highly contagious within households, in particular in small households in urban communities. Our results suggest that water disinfection and case isolation are associated with reduction of outbreaks in resource-limited communities. [ABSTRACT FROM AUTHOR]- Published
- 2018
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110. Epidemiological inferences using public information, influenza H7N9 epidemic in China
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Lau, Eric H.Y., primary, Zheng, Jiandong, additional, Tsang, Tim K., additional, Liao, Qiaohong, additional, Lewis, Bryan, additional, Brownstein, John S., additional, Sanders, Sharon, additional, Mekaru, Sumiko R., additional, Rivers, Caitlin, additional, Leung, Gabriel M., additional, Feng, Luzhao, additional, Cowling, Benjamin J., additional, and Yu, Hongjie, additional
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- 2015
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111. Accuracy of epidemiological inferences based on publicly available information: retrospective comparative analysis of line lists of human cases infected with influenza A(H7N9) in China
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Lau, Eric H. Y., Zheng, Jiandong, Tsang, Tim K., Liao, Qiaohong, Lewis, Bryan L., Brownstein, John S., Sanders, Sharon, Wong, Jessica Y., Mekaru, Sumiko R., Rivers, Caitlin, Wu, Peng, Jiang, Hui, Li, Yu, Yu, Jianxing, Zhang, Qian, Chang, Zhaorui, Liu, Fengfeng, Peng, Zhibin, Leung, Gabriel M., Feng, Luzhao, Cowling, Benjamin J., Yu, Hongjie, Lau, Eric H. Y., Zheng, Jiandong, Tsang, Tim K., Liao, Qiaohong, Lewis, Bryan L., Brownstein, John S., Sanders, Sharon, Wong, Jessica Y., Mekaru, Sumiko R., Rivers, Caitlin, Wu, Peng, Jiang, Hui, Li, Yu, Yu, Jianxing, Zhang, Qian, Chang, Zhaorui, Liu, Fengfeng, Peng, Zhibin, Leung, Gabriel M., Feng, Luzhao, Cowling, Benjamin J., and Yu, Hongjie
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Background Appropriate public health responses to infectious disease threats should be based on best-available evidence, which requires timely reliable data for appropriate analysis. During the early stages of epidemics, analysis of ‘line lists’ with detailed information on laboratory-confirmed cases can provide important insights into the epidemiology of a specific disease. The objective of the present study was to investigate the extent to which reliable epidemiologic inferences could be made from publicly-available epidemiologic data of human infection with influenza A(H7N9) virus. Methods We collated and compared six different line lists of laboratory-confirmed human cases of influenza A(H7N9) virus infection in the 2013 outbreak in China, including the official line list constructed by the Chinese Center for Disease Control and Prevention plus five other line lists by HealthMap, Virginia Tech, Bloomberg News, the University of Hong Kong and FluTrackers, based on publicly-available information. We characterized clinical severity and transmissibility of the outbreak, using line lists available at specific dates to estimate epidemiologic parameters, to replicate real-time inferences on the hospitalization fatality risk, and the impact of live poultry market closure. Results Demographic information was mostly complete (less than 10% missing for all variables) in different line lists, but there were more missing data on dates of hospitalization, discharge and health status (more than 10% missing for each variable). The estimated onset to hospitalization distributions were similar (median ranged from 4.6 to 5.6 days) for all line lists. Hospital fatality risk was consistently around 20% in the early phase of the epidemic for all line lists and approached the final estimate of 35% afterwards for the official line list only. Most of the line lists estimated >90% reduction in incidence rates after live poultry market closures in Shanghai, Nanjing and Hangzhou. Conclusio
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- 2014
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112. Preliminary Epidemiologic Assessment of Human Infections With Highly Pathogenic Avian Influenza A(H5N6) Virus, China.
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Hui Jiang, Peng Wu, Uyeki, Timothy M., Jianfeng He, Zhihong Deng, Wen Xu, Qiang Lv, Jin Zhang, Yang Wu, Tsang, Tim K., Min Kang, Jiandong Zheng, Lili Wang, Bingyi Yang, Ying Qin, Luzhao Feng, Fang, Vicky J., Gao, George F., Leung, Gabriel M., and Hongjie Yu
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AVIAN influenza A virus ,AVIAN influenza ,AVIAN influenza treatment ,EPIDEMIOLOGY ,MEDICAL care ,PATIENTS - Abstract
Background. Since 2014, 17 human cases of infection with the newly emerged highly pathogenic avian influenza A(H5N6) virus have been identified in China to date. The epidemiologic characteristics of laboratory-confirmed A(H5N6) cases were compared to A(H5N1) and A(H7N9) cases in mainland China. Methods. Data on laboratory-confirmed H5N6, H5N1, and H7N9 cases identified in mainland China were analyzed to compare epidemiologic characteristics and clinical severity. Severity of confirmed H5N6, H5N1 and H7N9 cases was estimated based on the risk of severe outcomes in hospitalized cases. Results. H5N6 cases were older than H5N1 cases with a higher prevalence of underlying medical conditions but younger than H7N9 cases. Epidemiological time-to-event distributions were similar among cases infected with the 3 viruses. In comparison to a fatality risk of 70% (30/43) for hospitalized H5N1 cases and 41% (319/782) for hospitalized H7N9 cases, 12 (75%) out of the 16 hospitalized H5N6 cases were fatal, and 15 (94%) required mechanical ventilation. Conclusion. Similar epidemiologic characteristics and high severity were observed in cases of H5N6 and H5N1 virus infection, whereas severity of H7N9 virus infections appeared lower. Continued surveillance of human infections with avian influenza A viruses remains an essential component of pandemic influenza preparedness. [ABSTRACT FROM AUTHOR]
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- 2017
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113. A clinical prediction rule for diagnosing human infections with avian influenza A(H7N9) in a hospital emergency department setting
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Liao, Qiaohong, primary, Ip, Dennis K M, additional, Tsang, Tim K, additional, Cao, Bin, additional, Jiang, Hui, additional, Liu, Fengfeng, additional, Zheng, Jiandong, additional, Peng, Zhibin, additional, Wu, Peng, additional, Huai, Yang, additional, Lau, Eric H Y, additional, Feng, Luzhao, additional, Leung, Gabriel M, additional, Yu, Hongjie, additional, and Cowling, Benjamin J, additional
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- 2014
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114. Investigating the relationship between stroke and serum fatty acids in hypertensive population
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Li, Chao, primary, Peng, Hao, additional, Cai, Xiao-Qin, additional, Tsang, Tim K., additional, Shen, Heng-Shan, additional, Wu, Xin-Han, additional, Zhou, Yi-Bin, additional, and Cheung, Bernard MY, additional
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- 2014
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115. Accuracy of epidemiological inferences based on publicly available information: retrospective comparative analysis of line lists of human cases infected with influenza A(H7N9) in China
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Lau, Eric HY, primary, Zheng, Jiandong, additional, Tsang, Tim K, additional, Liao, Qiaohong, additional, Lewis, Bryan, additional, Brownstein, John S, additional, Sanders, Sharon, additional, Wong, Jessica Y, additional, Mekaru, Sumiko R, additional, Rivers, Caitlin, additional, Wu, Peng, additional, Jiang, Hui, additional, Li, Yu, additional, Yu, Jianxing, additional, Zhang, Qian, additional, Chang, Zhaorui, additional, Liu, Fengfeng, additional, Peng, Zhibin, additional, Leung, Gabriel M, additional, Feng, Luzhao, additional, Cowling, Benjamin J, additional, and Yu, Hongjie, additional
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- 2014
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116. Human infection with avian influenza A H7N9 virus: an assessment of clinical severity
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Yu, Hongjie, primary, Cowling, Benjamin J, additional, Feng, Luzhao, additional, Lau, Eric HY, additional, Liao, Qiaohong, additional, Tsang, Tim K, additional, Peng, Zhibin, additional, Wu, Peng, additional, Liu, Fengfeng, additional, Fang, Vicky J, additional, Zhang, Honglong, additional, Li, Ming, additional, Zeng, Lingjia, additional, Xu, Zhen, additional, Li, Zhongjie, additional, Luo, Huiming, additional, Li, Qun, additional, Feng, Zijian, additional, Cao, Bin, additional, Yang, Weizhong, additional, Wu, Joseph T, additional, Wang, Yu, additional, and Leung, Gabriel M, additional
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- 2013
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117. Comparative epidemiology of human infections with avian influenza A H7N9 and H5N1 viruses in China: a population-based study of laboratory-confirmed cases
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Cowling, Benjamin J, primary, Jin, Lianmei, additional, Lau, Eric HY, additional, Liao, Qiaohong, additional, Wu, Peng, additional, Jiang, Hui, additional, Tsang, Tim K, additional, Zheng, Jiandong, additional, Fang, Vicky J, additional, Chang, Zhaorui, additional, Ni, Michael Y, additional, Zhang, Qian, additional, Ip, Dennis KM, additional, Yu, Jianxing, additional, Li, Yu, additional, Wang, Liping, additional, Tu, Wenxiao, additional, Meng, Ling, additional, Wu, Joseph T, additional, Luo, Huiming, additional, Li, Qun, additional, Shu, Yuelong, additional, Li, Zhongjie, additional, Feng, Zijian, additional, Yang, Weizhong, additional, Wang, Yu, additional, Leung, Gabriel M, additional, and Yu, Hongjie, additional
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- 2013
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118. Human Infection with Influenza A(H7N9) Virus during 3 Major Epidemic Waves, China, 2013-2015.
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Peng Wu, Zhibin Peng, Fang, Vicky J., Luzhao Feng, Tsang, Tim K., Hui Jiang, Lau, Eric H. Y., Juan Yang, Jiandong Zheng, Ying Qin, Zhongjie Li, Leung, Gabriel M., Hongjie Yu, Cowling, Benjamin J., Wu, Peng, Peng, Zhibin, Feng, Luzhao, Jiang, Hui, Yang, Juan, and Zheng, Jiandong
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AVIAN influenza epidemiology ,H7N9 Influenza ,EPIDEMIOLOGY ,ARTIFICIAL respiration ,AVIAN influenza treatment ,PUBLIC health ,INFECTIOUS disease transmission ,INFLUENZA transmission ,INFLUENZA epidemiology ,ANIMAL experimentation ,COMPARATIVE studies ,EPIDEMICS ,HISTORY ,HOSPITAL care ,INFLUENZA ,RESEARCH methodology ,MEDICAL cooperation ,MORTALITY ,PUBLIC health surveillance ,RESEARCH ,RESEARCH funding ,EVALUATION research ,INFLUENZA A virus ,GENOTYPES - Abstract
Since March 2013, a novel influenza A(H7N9) virus has caused 3 epidemic waves of human infection in mainland China. We analyzed data from patients with laboratory-confirmed influenza A(H7N9) virus infection to estimate the risks for severe outcomes after hospitalization across the 3 waves. We found that hospitalized patients with confirmed infections in waves 2 and 3 were younger and more likely to be residing in small cities and rural areas than were patients in wave 1; they also had a higher risk for death, after adjustment for age and underlying medical conditions. Risk for death among hospitalized patients during waves 2 and 3 was lower in Jiangxi and Fujian Provinces than in eastern and southern provinces. The variation in risk for death among hospitalized case-patients in different areas across 3 epidemic waves might be associated with differences in case ascertainment, changes in clinical management, or virus genetic diversity. [ABSTRACT FROM AUTHOR]
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- 2016
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119. Comparative Epidemiology of Influenza B Yamagata- and Victoria-Lineage Viruses in Households.
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Cuiling Xu, Kwok-Hung Chan, Tsang, Tim K., Fang, Vicky J., Fung, Rita O. P., Ip, Dennis K. M., Cauchemez, Simon, Leung, Gabriel M., Peiris, J. S. Malik, and Cowling, Benjamin J.
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INFLUENZA epidemiology ,POLYMERASE chain reaction ,RESEARCH funding ,STATISTICAL power analysis ,INFLUENZA B virus ,DATA analysis software ,STATISTICAL models ,KAPLAN-Meier estimator - Abstract
Influenza B viruses split into 2 distinct lineages in the early 1980s, commonly named the Victoria and Yamagata lineages. There are few data on the comparative epidemiology of Victoria- and Yamagata-lineage viruses. In 2007-2011,we enrolled 75 and 34 households containing index patients with acute respiratory illness who tested positive for Yamagata- and Victoria-lineage viruses, respectively, from outpatient clinics in Hong Kong, China. These index patients and their household contacts were followed up for 7-10 days. We examined overall risk of polymerase chain reaction--confirmed infection among household contacts and the risk of secondary infection within households using an individual-based hazard model that accounted for tertiary transmission and infections occurring outside the household. We found that for Victoria-lineage viruses, the risk of within-household infection among household contacts aged ≤15 years was significantly higher (risk ratio = 12.9, 95% credibility interval: 4.2, 43.6) than that for older household contacts, while for Yamagata-lineage viruses, the risk of within-household infection for household contacts did not differ by age. Influenza B Yamagata- and Victoria-lineage viruses have similar characteristics in terms of viral shedding and clinical illness. The mechanisms underlying these epidemiologic differences deserve further investigation. [ABSTRACT FROM AUTHOR]
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- 2015
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120. Differences in the Epidemiology of Human Cases of Avian Influenza A(H7N9) and A(H5N1) Viruses Infection.
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Ying Qin, Horby, Peter W., Tsang, Tim K., Enfu Chen, Lidong Gao, Jianming Ou, Tran Hien Nguyen, Tran Nhu Duong, Gasimov, Viktor, Luzhao Feng, Peng Wu, Hui Jiang, Xiang Ren, Zhibin Peng, Sa Li, Ming Li, Jiandong Zheng, Shelan Liu, Shixiong Hu, and Rongtao Hong
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AVIAN influenza A virus ,H7N9 Influenza ,H5N1 Influenza ,EPIDEMIOLOGY ,BLOOD diseases ,INFECTION - Abstract
Background. The pandemic potential of avian influenza viruses A(H5N1) and A(H7N9) remains an unresolved but critically important question. Methods. We compared the characteristics of sporadic and clustered cases of human H5N1 and H7N9 infection, estimated the relative risk of infection in blood-related contacts, and the reproduction number (R). Results. We assembled and analyzed data on 720 H5N1 cases and 460 H7N9 cases up to 2 November 2014. The severity and average age of sporadic/index cases of H7N9 was greater than secondary cases (71% requiring intensive care unit admission vs 33%, P = .007; median age 59 years vs 31, P < .001). We observed no significant differences in the age and severity between sporadic/index and secondary H5N1 cases. The upper limit of the 95% confidence interval (CI) for R was 0.12 for H5N1 and 0.27 for H7N9. A higher proportion of H5N1 infections occurred in clusters (20%) compared to H7N9 (8%). The relative risk of infection in blood-related contacts of cases compared to unrelated contacts was 8.96 for H5N1 (95% CI, 1.30, 61.86) and 0.80 for H7N9 (95% CI, .32, 1.97). Conclusions. The results are consistent with an ascertainment bias towards severe and older cases for sporadic H7N9 but not for H5N1. The lack of evidence for ascertainment bias in sporadic H5N1 cases, the more pronounced clustering of cases, and the higher risk of infection in blood-related contacts, support the hypothesis that susceptibility to H5N1 may be limited and familial. This analysis suggests the potential pandemic risk may be greater for H7N9 than H5N1. [ABSTRACT FROM AUTHOR]
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- 2015
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121. Poultry Market Closures and Human Infection with Influenza A(H7N9) Virus, China, 2013-14.
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Peng Wu, Hui Jiang, Wu, Joseph T., Enfu Chen, Jianfeng He, Hang Zhou, Lan Wei, Juan Yang, Bingyi Yang, Ying Qin, Fang, Vicky J., Ming Li, Tsang, Tim K., Jiandong Zheng, Lau, Eric H. Y., Yu Cao, Chengliang Chai, Haojie Zhong, Zhongjie Li, and Leung, Gabriel M.
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POULTRY industry ,INFLUENZA A virus, H7N9 subtype ,INFLUENZA A virus ,INFLUENZA prevention ,ANIMAL industry - Abstract
Closure of live poultry markets was implemented in areas affected by the influenza virus A(H7N9) outbreak in China during winter, 2013-14. Our analysis showed that closing live poultry markets in the most affected cities of Guangdong and Zhejiang provinces was highly effective in reducing the risk for H7N9 infection in humans. [ABSTRACT FROM AUTHOR]
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- 2014
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122. Comparison of control and transmission of COVID-19 across epidemic waves in Hong Kong: an observational study
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Yang, Bingyi, Lin, Yun, Xiong, Weijia, Liu, Chang, Gao, Huizhi, Ho, Faith, Zhou, Jiayi, Zhang, Ru, Wong, Jessica Y., Cheung, Justin K., Lau, Eric H.Y., Tsang, Tim K., Xiao, Jingyi, Wong, Irene O.L., Martín-Sánchez, Mario, Leung, Gabriel M., Cowling, Benjamin J., and Wu, Peng
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Hong Kong contained COVID-19 for two years but experienced a large epidemic of Omicron BA.2 in early 2022 and endemic transmission of Omicron subvariants thereafter. We reflected on pandemic preparedness and responses by assessing COVID-19 transmission and associated disease burden in the context of implementation of various public health and social measures (PHSMs).
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- 2023
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123. A clinical prediction rule for diagnosing human infections with avian influenza A(H7N9) in a hospital emergency department setting.
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Qiaohong Liao, Ip, Dennis K. M., Tsang, Tim K., Bin Cao, Hui Jiang, Fengfeng Liu, Jiandong Zheng, Zhibin Peng, Peng Wu, Yang Huai, Lau, Eric H. Y., Luzhao Feng, Leung, Gabriel M., Hongjie Yu, and Cowling, Benjamin J.
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INFECTION ,AVIAN influenza diagnosis ,HOSPITAL emergency services ,CLINICAL prediction rules ,DECISION making in clinical medicine ,MEDICAL triage ,MEDICAL care ,H7N9 Influenza ,DIAGNOSIS - Abstract
Background Human infections with avian influenza A(H7N9) virus are associated with severe illness and high mortality. To better inform triage decisions of hospitalization and management, we developed a clinical prediction rule for diagnosing patients with A(H7N9) and determined its predictive performance. Methods Clinical details on presentation of adult patients hospitalized with either A(H7N9)(n = 121) in China from March to May 2013 or other causes of acute respiratory infections (n = 2,603) in Jingzhou City, China from January 2010 through September 2012 were analyzed. A clinical prediction rule was developed using a two-step coefficient-based multivariable logistic regression scoring method and evaluated with internal validation by bootstrapping. Results In step 1, predictors for A(H7N9) included male sex, poultry exposure history, and fever, haemoptysis, or shortness of breath on history and physical examination. In step 2, haziness or pneumonic consolidation on chest radiographs and leukopenia were also associated with a higher probability of A(H7N9). The observed risk of A(H7N9) was 0.3% for those assigned to the low-risk group and 2.5%, 4.3%, and 44.0% for tertiles 1 through 3, respectively, in the high-risk group. This prediction rule achieved good model performance, with an optimism-corrected sensitivity of 0.93, a specificity of 0.80, and an area under the receiver-operating characteristic curve of 0.96. Conclusions A simple decision rule based on data readily obtainable in the setting of patients' first clinical presentations from the first wave of the A/H7N9 epidemic in China has been developed. This prediction rule has achieved good model performance in predicting their risk of A(H7N9) infection and should be useful in guiding important clinical and public health decisions in a timely and objective manner. Data to be gathered with its use in the current evolving second wave of the A/H7N9 epidemic in China will help to inform its performance in the field and contribute to its further refinement. [ABSTRACT FROM AUTHOR]
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- 2014
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124. Inferring time-varying generation time, serial interval, and incubation period distributions for COVID-19
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Dongxuan Chen, Yiu-Chung Lau, Xiao-Ke Xu, Lin Wang, Zhanwei Du, Tim K. Tsang, Peng Wu, Eric H. Y. Lau, Jacco Wallinga, Benjamin J. Cowling, Sheikh Taslim Ali, Lau, Yiu-Chung [0000-0001-6618-9094], Wang, Lin [0000-0002-5371-2138], Du, Zhanwei [0000-0002-2020-767X], Tsang, Tim K [0000-0001-5037-6776], Wu, Peng [0000-0003-1157-9401], Lau, Eric HY [0000-0002-6688-9637], Cowling, Benjamin J [0000-0002-6297-7154], Ali, Sheikh Taslim [0000-0002-8631-9076], and Apollo - University of Cambridge Repository
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China ,Multidisciplinary ,Time Factors ,SARS-CoV-2 ,article ,General Physics and Astronomy ,COVID-19 ,General Chemistry ,631/114/2415 ,692/700/478/174 ,General Biochemistry, Genetics and Molecular Biology ,Infectious Disease Incubation Period ,Humans ,692/699/255 ,129 ,631/326/596/4130 - Abstract
BackgroundThe generation time distribution, reflecting the time between successive infections in transmission chains, is one of the fundamental epidemiological parameters for describing COVID-19 transmission dynamics. However, because exact infection times are rarely known, it is often approximated by the serial interval distribution, reflecting the time between illness onsets of infector and infectee. This approximation holds under the assumption that infectors and infectees share the same incubation period distribution, which may not always be true.MethodsWe analyzed data on observed incubation period and serial interval distributions in China, during January and February 2020, under different sampling approaches, and developed an inferential framework to estimate the generation time distribution that accounts for variation over time due to changes in epidemiology, sampling biases and public health and social measures.ResultsWe analyzed data on a total of 2989 confirmed cases for COVID-19 during January 1 to February 29, 2020 in Mainland China. During the study period, the empirical forward serial interval decreased from a mean of 8.90 days to 2.68 days. The estimated mean backward incubation period of infectors increased from 3.77 days to 9.61 days, and the mean forward incubation period of infectees also increased from 5.39 days to 7.21 days. The estimated mean forward generation time decreased from 7.27 days (95% confidence interval: 6.42, 8.07) to 4.21 days (95% confidence interval: 3.70, 4.74) days by January 29. We used simulations to examine the sensitivity of our modelling approach to a number of assumptions and alternative dynamics.ConclusionsThe proposed method can provide more reliable estimation of the temporal variation in the generation time distribution, enabling proper assessment of transmission dynamics.
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- 2022
125. Human infection with avian influenza A H7N9 virus: an assessment of clinical severity.
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Hongjie Yu, Cowling, Benjamin J., Luzhao Feng, Lau, Eric H. Y., Qiaohong Liao, Tsang, Tim K., Zhibin Peng, Peng Wu, Fengfeng Liu, Fang, Vicky J., Honglong Zhang, Ming Li, Lingjia Zeng, Zhen Xu, Zhongjie Li, Huiming Luo, Qun Li, Zijian Feng, Bin Cao, and Weizhong Yang
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H7N9 Influenza , *H5N1 Influenza , *INFLUENZA viruses , *EPIDEMIOLOGY , *ARTIFICIAL respiration , *INTENSIVE care units - Abstract
Background Characterisation of the severity profile of human infections with influenza viruses of animal origin is a part of pandemic risk assessment, and an important part of the assessment of disease epidemiology. Our objective was to assess the clinical severity of human infections with avian influenza A H7N9 virus, which emerged in China in early 2013. Methods We obtained information about laboratory-confirmed cases of avian influenza A H7N9 virus infection reported as of May 28, 2013, from an integrated database built by the Chinese Center for Disease Control and Prevention. We estimated the risk of fatality, mechanical ventilation, and admission to the intensive care unit for patients who required hospital admission for medical reasons. We also used information about laboratory-confirmed cases detected through sentinel influenza-like illness surveillance to estimate the symptomatic case fatality risk. Findings Of 123 patients with laboratory-confirmed avian influenza A H7N9 virus infection who were admitted to hospital, 37 (30%) had died and 69 (56%) had recovered by May 28, 2013. After we accounted for incomplete data for 17 patients who were still in hospital, we estimated the fatality risk for all ages to be 36% (95% CI 26-45) on admission to hospital. Risks of mechanical ventilation or fatality (69%, 95% CI 60-77) and of admission to an intensive care unit, mechanical ventilation, or fatality (83%, 76-90) were high. With assumptions about coverage of the sentinel surveillance network and health-care-seeking behaviour for patients with influenza-like illness associated with influenza A H7N9 virus infection, and pro-rata extrapolation, we estimated that the symptomatic case fatality risk could be between 160 (63-460) and 2800 0000-9400) per 100 000 symptomatic cases. Interpretation Human infections with avian influenza A H7N9 virus seem to be less serious than has been previously reported. Many mild cases might already have occurred. Continued vigilance and sustained intensive control efforts are needed to minimise the risk of human infection. Funding Chinese Ministry of Science and Technology; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; US National Institute of Allergy and Infectious Disease; and the US National Institutes of Health. [ABSTRACT FROM AUTHOR]
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- 2013
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126. Interplay between viral shedding, age, and symptoms on individual infectiousness of influenza cases in households.
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Zhang C, Fang VJ, Chan KH, Leung GM, Ip DKM, Peiris JSM, Cowling BJ, and Tsang TK
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Background: Understanding factors affecting the infectiousness of influenza cases is crucial for disease prevention and control. Viral shedding is expected to correlate with infectiousness of cases, but it is strongly associated with age and the presence of symptoms., Methods: To elucidate this complex interplay, we analyze with an individual-based household transmission model a detailed household transmission study of influenza with 442 households and 1710 individuals from 2008 to 2017 in Hong Kong, to characterize the household transmission dynamics and identify factors affecting transmissions., Results: We estimate that age, fever symptoms and viral load were all associated with higher infectiousness. However, by model comparison, the best model includes age and fever as factors affecting individual infectiousness, and estimates that pre-school and school-age children were 317% (95% credible interval (CrI): 103%, 1042%) and 161% (95% CrI: 33%, 601%) more infectious than adults respectively, and patients having fever had 146% (95% CrI: 37%, 420%) higher infectiousness. Adding heterogeneity on individual infectiousness of cases does not improve the model fit, suggesting these factors could explain the difference in individual infectiousness., Conclusions: Our study clarifies the contribution of age, symptoms and viral shedding to individual infectiousness of influenza cases in households., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
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- 2024
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127. Prior infections and effectiveness of SARS-CoV-2 vaccine in test-negative studies: A systematic review and meta-analysis.
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Tsang TK, Sullivan SG, Huang X, Wang C, Wang Y, Nealon J, Yang B, Ainslie KEC, and Cowling BJ
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Prior infection with SARS-CoV-2 can provide protection against infection and severe COVID-19. We aimed to determine the impact of pre-existing immunity on the vaccine effectiveness (VE) estimates. We systematically reviewed and meta-analysed 66 test-negative design (TND) studies that examined VE against infection or severe disease (hospitalization, ICU admission, or death) for primary vaccination series. Pooled VE among studies that included people with prior COVID-19 infection was lower against infection (pooled VE: 77%; 95% confidence interval (CI): 72%, 81%) and severe disease (pooled VE: 86%; 95% CI: 83%, 89%), compared with studies that excluded people with prior COVID-19 infection (pooled VE against infection: 87%; 95% CI: 85%, 89%; pooled VE against severe disease: 93%; 95% CI: 91%, 95%). There was a negative correlation between VE estimates against infection and severe disease, and the cumulative incidence of cases before the start of the study or incidence rates during the study period. We found clear empirical evidence that higher levels of pre-existing immunity were associated with lower VE estimates. Prior infections should be treated as both a confounder and effect modificatory when the policies target the whole population or stratified by infection history, respectively., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2024
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128. Evaluating the impact of extended dosing intervals on mRNA COVID-19 vaccine effectiveness in adolescents.
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Tsang TK, Sullivan SG, Meng Y, Lai FTT, Fan M, Huang X, Lin Y, Peng L, Zhang C, Yang B, Ainslie KEC, and Cowling BJ
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Extending the dosing interval of a primary series of mRNA COVID-19 vaccination has been employed to reduce myocarditis risk in adolescents, but previous evaluation of impact on vaccine effectiveness (VE) is limited to risk after second dose. Here, we quantified the impact of the dosing interval based on case notifications and vaccination uptake in Hong Kong from January to April 2022. We estimated that the hazard ratio (HR) and odds ratio (OR) of infections after the second dose for extended (28 days or more) versus regular (21-27 days) dosing intervals ranged from 0.86 to 0.99 from calendar-time proportional hazards models, and from 0.85 to 0.87 from matching approaches, respectively. Adolescents in the extended dosing groups (including those who did not receive a second dose in the study period) had a higher hazard of infection than those with a regular dosing interval during the intra-dose period (HR: 1.66; 95% CI: 1.07, 2.59; p = 0.02) after the first dose. Implementing an extended dosing interval should consider multiple factors including the degree of myocarditis risk, the degree of protection afforded by each dose, and the extra protection achievable using an extended dosing interval., Competing Interests: Potential conflicts of interest. BJC reports honoraria from AstraZeneca, Fosun Pharma, GSK, Haleon, Moderna, Novavax, Pfizer, Roche and Sanofi Pasteur. SGS reports honoraria from CSL Seqirus, Evo Health, Moderna, Novavax and Pfizer. All other authors report no other potential conflicts of interest.
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- 2024
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129. Decreased risk of non-influenza respiratory infection after influenza B virus infection in children.
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Tsang TK, Du RQR, Fang VJ, Lau EHY, Chan KH, Chu DKW, Ip DKM, Peiris JSM, Leung GM, Cauchemez S, and Cowling BJ
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- Child, Humans, Influenza B virus, Influenza, Human epidemiology, Orthomyxoviridae Infections, Orthomyxoviridae, Herpesviridae Infections, Influenza Vaccines, Respiratory Tract Infections epidemiology
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Previous studies suggest that influenza virus infection may provide temporary non-specific immunity and hence lower the risk of non-influenza respiratory virus infection. In a randomized controlled trial of influenza vaccination, 1 330 children were followed-up in 2009-2011. Respiratory swabs were collected when they reported acute respiratory illness and tested against influenza and other respiratory viruses. We used Poisson regression to compare the incidence of non-influenza respiratory virus infection before and after influenza virus infection. Based on 52 children with influenza B virus infection, the incidence rate ratio (IRR) of non-influenza respiratory virus infection after influenza virus infection was 0.47 (95% confidence interval: 0.27-0.82) compared with before infection. Simulation suggested that this IRR was 0.87 if the temporary protection did not exist. We identified a decreased risk of non-influenza respiratory virus infection after influenza B virus infection in children. Further investigation is needed to determine if this decreased risk could be attributed to temporary non-specific immunity acquired from influenza virus infection.
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- 2024
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130. Comparison of control and transmission of COVID-19 across epidemic waves in Hong Kong: an observational study.
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Yang B, Lin Y, Xiong W, Liu C, Gao H, Ho F, Zhou J, Zhang R, Wong JY, Cheung JK, Lau EHY, Tsang TK, Xiao J, Wong IOL, Martín-Sánchez M, Leung GM, Cowling BJ, and Wu P
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Background: Hong Kong contained COVID-19 for two years but experienced a large epidemic of Omicron BA.2 in early 2022 and endemic transmission of Omicron subvariants thereafter. We reflected on pandemic preparedness and responses by assessing COVID-19 transmission and associated disease burden in the context of implementation of various public health and social measures (PHSMs)., Methods: We examined the use and impact of pandemic controls in Hong Kong by analysing data on more than 1.7 million confirmed COVID-19 cases and characterizing the temporal changes non-pharmaceutical and pharmaceutical interventions implemented from January 2020 through to 30 December 2022. We estimated the daily effective reproductive number ( R
t ) to track changes in transmissibility and effectiveness of community-based measures against infection over time. We examined the temporal changes of pharmaceutical interventions, mortality rate and case-fatality risks (CFRs), particularly among older adults., Findings: Hong Kong experienced four local epidemic waves predominated by the ancestral strain in 2020 and early 2021 and prevented multiple SARS-CoV-2 variants from spreading in the community before 2022. Strict travel-related, case-based, and community-based measures were increasingly tightened in Hong Kong over the first two years of the pandemic. However, even very stringent measures were unable to contain the spread of Omicron BA.2 in Hong Kong. Despite high overall vaccination uptake (>70% with at least two doses), high mortality was observed during the Omicron BA.2 wave due to lower vaccine coverage (42%) among adults ≥65 years of age. Increases in antiviral usage and vaccination uptake over time through 2022 was associated with decreased case fatality risks., Interpretation: Integrated strict measures were able to reduce importation risks and interrupt local transmission to contain COVID-19 transmission and disease burden while awaiting vaccine development and rollout. Increasing coverage of pharmaceutical interventions among high-risk groups reduced infection-related mortality and mitigated the adverse health impact of the pandemic., Funding: Health and Medical Research Fund., Competing Interests: BJC consults for AstraZeneca, Fosun Pharma, GSK, Haleon, Moderna, Novavax, Pfizer, Roche, and Sanofi Pasteur. The authors report no other potential conflicts of interest., (© 2023 The Author(s).)- Published
- 2023
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131. Characterizing Human Collective Behaviors During COVID-19 - Hong Kong SAR, China, 2020.
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Du Z, Zhang X, Wang L, Yao S, Bai Y, Tan Q, Xu X, Pei S, Xiao J, Tsang TK, Liao Q, Lau EHY, Wu P, Gao C, and Cowling BJ
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What Is Already Known About This Topic?: People are likely to engage in collective behaviors online during extreme events, such as the coronavirus disease 2019 (COVID-19) crisis, to express awareness, take action, and work through concerns., What Is Added by This Report?: This study offers a framework for evaluating interactions among individuals' emotions, perceptions, and online behaviors in Hong Kong Special Administrative Region (SAR) during the first two waves of COVID-19 (February to June 2020). Its results indicate a strong correlation between online behaviors, such as Google searches, and the real-time reproduction numbers. To validate the model's output of risk perception, this investigation conducted 10 rounds of cross-sectional telephone surveys on 8,593 local adult residents from February 1 through June 20 in 2020 to quantify risk perception levels over time., What Are the Implications for Public Health Practice?: Compared to the survey results, the estimates of the risk perception of individuals using our network-based mechanistic model capture 80% of the trend of people's risk perception (individuals who are worried about being infected) during the studied period. We may need to reinvigorate the public by involving people as part of the solution that reduced the risk to their lives., Competing Interests: BJC consults for AstraZeneca, Fosun Pharma, GlaxoSmithKline, Moderna, Pfizer, Roche and Sanofi Pasteur. BJC is supported by the AIR@innoHK program of the Innovation and Technology Commission of the Hong Kong SAR Government. No other conflicts of interest reported., (Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2023.)
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- 2023
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132. The differential importation risks of COVID-19 from inbound travellers and the feasibility of targeted travel controls: A case study in Hong Kong.
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Yang B, Tsang TK, Wong JY, He Y, Gao H, Ho F, Lau EHY, Wu P, Sullivan SG, and Cowling BJ
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Background: Many countries/regions implemented strict border measures (e.g., 14-day quarantines) as a blanket policy to prevent COVID-19 importations, while proposed "travel bubbles" as an alternative to reduce the impact of border controls. We aim to examine the differential importation risks with departure origins and post-arrival controls., Methods: We developed a Bayesian framework to model disease progress of COVID-19 and the effectiveness of travel measures and inferred the origin-specific disease prevalence among inbound travellers, using data on passengers arriving in Hong Kong and laboratory-confirmed imported cases. We estimated the origin-specific risks of releasing infectious travellers under different control strategies and traveller volumes. We also estimated the risk of having released infectious travellers when a resurgence occurs in departure locations with no imported cases during a certain period., Findings: Under the then strict controls of 14-day quarantine and testing on day 12, the Philippines imposed the greatest importation risk among the studied countries/regions (95.8% of releasing at least one infectious traveller, 95% credible interval (CrI), 94.8-96.6%). This was higher than that from low prevalence countries/regions (e.g., 23.4%, 95% CrI, 21.6-25.3% for Taiwan) if controls relaxed (i.e., 7-day quarantine and test on day 5). Increased traveller volumes and resurgence in departure locations with low prevalence under relaxed controls did not impose a greater importation risk than high prevalence locations under stricter controls., Interpretation: Moderate relaxation of control measures for travellers arriving from low prevalence locations did not impose higher risks of community outbreaks than strict controls on travellers from high prevalence locations., Funding: Health and Medical Research Fund, Hong Kong., Competing Interests: BJC consults for Roche, GSK, Moderna, AstraZeneca and Sanofi Pasteur and is supported by the AIR@innoHK program of the Innovation and Technology Commission of the Hong Kong SAR Government. SGS reports unpaid consulting for Sanofi Pasteur. The authors report no other potential conflicts of interest., (© 2021 The Author(s). Published by Elsevier Ltd.)
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- 2021
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133. International risk of the new variant COVID-19 importations originating in the United Kingdom.
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Du Z, Wang L, Yang B, Ali ST, Tsang TK, Shan S, Wu P, Lau EHY, Cowling BJ, and Meyers LA
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A fast-spreading SARS-CoV-2 variant identified in the United Kingdom in December 2020 has raised international alarm. We estimate that, in all 15 countries analyzed, there is at least a 50% chance the variant was imported by travelers from the United Kingdom by December 7th.
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- 2021
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