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Wong JY, Cheung JK, Lin Y, Bond HS, Lau EHY, Ip DKM, Cowling BJ, Wu P. Intrinsic and Effective Severity of Coronavirus Disease 2019 Cases Infected With the Ancestral Strain and Omicron BA.2 Variant in Hong Kong. J Infect Dis 2023; 228:1231-1239. [PMID: 37368235 DOI: 10.1093/infdis/jiad236] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/25/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023] Open
Abstract
BACKGROUND Understanding severity of infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants is crucial to inform public health measures. Here we used coronavirus disease 2019 (COVID-19) patient data from Hong Kong to characterize the severity profile of COVID-19. METHODS Time-varying and age-specific effective severity measured by case hospitalization risk and hospitalization fatality risk was estimated with all individual COVID-19 case data collected in Hong Kong from 23 January 2020 through 26 October 2022 over 6 epidemic waves. The intrinsic severity of Omicron BA.2 was compared with the estimate for the ancestral strain with the data from unvaccinated patients without previous infections. RESULTS With 32 222 COVID-19 hospitalizations and 9669 deaths confirmed over 6 epidemic waves, the time-varying hospitalization fatality risk dramatically increased from <10% before the largest fifth wave of Omicron BA.2 to 41% during the peak of the fifth wave when hospital resources were severely constrained. The age-specific fatality risk in unvaccinated hospitalized Omicron cases was comparable to the estimates for unvaccinated cases with the ancestral strain. During epidemics predominated by Omicron BA.2, fatality risk was highest among older unvaccinated patients. CONCLUSIONS Omicron has comparable intrinsic severity to the ancestral Wuhan strain, although the effective severity is substantially lower in Omicron cases due to vaccination.
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Affiliation(s)
- Jessica Y Wong
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Justin K Cheung
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Yun Lin
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Helen S Bond
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eric H Y Lau
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
| | - Dennis K M Ip
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Benjamin J Cowling
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
| | - Peng Wu
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
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Murphy C, Lim WW, Mills C, Wong JY, Chen D, Xie Y, Li M, Gould S, Xin H, Cheung JK, Bhatt S, Cowling BJ, Donnelly CA. Effectiveness of social distancing measures and lockdowns for reducing transmission of COVID-19 in non-healthcare, community-based settings. Philos Trans A Math Phys Eng Sci 2023; 381:20230132. [PMID: 37611629 PMCID: PMC10446910 DOI: 10.1098/rsta.2023.0132] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 05/23/2023] [Indexed: 08/25/2023]
Abstract
Social distancing measures (SDMs) are community-level interventions that aim to reduce person-to-person contacts in the community. SDMs were a major part of the responses first to contain, then to mitigate, the spread of SARS-CoV-2 in the community. Common SDMs included limiting the size of gatherings, closing schools and/or workplaces, implementing work-from-home arrangements, or more stringent restrictions such as lockdowns. This systematic review summarized the evidence for the effectiveness of nine SDMs. Almost all of the studies included were observational in nature, which meant that there were intrinsic risks of bias that could have been avoided were conditions randomly assigned to study participants. There were no instances where only one form of SDM had been in place in a particular setting during the study period, making it challenging to estimate the separate effect of each intervention. The more stringent SDMs such as stay-at-home orders, restrictions on mass gatherings and closures were estimated to be most effective at reducing SARS-CoV-2 transmission. Most studies included in this review suggested that combinations of SDMs successfully slowed or even stopped SARS-CoV-2 transmission in the community. However, individual effects and optimal combinations of interventions, as well as the optimal timing for particular measures, require further investigation. This article is part of the theme issue 'The effectiveness of non-pharmaceutical interventions on the COVID-19 pandemic: the evidence'.
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Affiliation(s)
- Caitriona Murphy
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Wey Wen Lim
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Cathal Mills
- Department of Statistics, University of Oxford, Oxford, UK
| | - Jessica Y. Wong
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Dongxuan Chen
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
- Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, New Territories, Hong Kong, People's Republic of China
| | - Yanmy Xie
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Mingwei Li
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
- Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, New Territories, Hong Kong, People's Republic of China
| | - Susan Gould
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Tropical and Infectious Disease Unit, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Hualei Xin
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Justin K. Cheung
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Samir Bhatt
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Kobenhavn, Denmark
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
| | - Benjamin J. Cowling
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
- Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, New Territories, Hong Kong, People's Republic of China
| | - Christl A. Donnelly
- Department of Statistics, University of Oxford, Oxford, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
- Pandemic Sciences Institute, University of Oxford, Oxford, UK
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Xin H, Wu P, Wong JY, Cheung JK, Lau EH, Leung GM, Cowling BJ, Nealon J. Hospitalizations and mortality during the first year of the COVID-19 pandemic in Hong Kong, China: An observational study. The Lancet Regional Health - Western Pacific 2023; 30:100645. [DOI: 10.1016/j.lanwpc.2022.100645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 11/24/2022]
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Mefsin YM, Chen D, Bond HS, Lin Y, Cheung JK, Wong JY, Ali ST, Lau EHY, Wu P, Leung GM, Cowling BJ. Epidemiology of Infections with SARS-CoV-2 Omicron BA.2 Variant, Hong Kong, January-March 2022. Emerg Infect Dis 2022; 28:1856-1858. [PMID: 35914518 PMCID: PMC9423929 DOI: 10.3201/eid2809.220613] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Our analysis of data collected from multiple epidemics in Hong Kong indicated a shorter serial interval and generation time of infections with the SARS-CoV-2 Omicron variant. The age-specific case-fatality risk for Omicron BA.2.2 case-patients without complete primary vaccination was comparable to that of persons infected with ancestral strains in earlier waves.
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McMenamin ME, Nealon J, Lin Y, Wong JY, Cheung JK, Lau EHY, Wu P, Leung GM, Cowling BJ. Vaccine effectiveness of one, two, and three doses of BNT162b2 and CoronaVac against COVID-19 in Hong Kong: a population-based observational study. Lancet Infect Dis 2022; 22:1435-1443. [PMID: 35850128 PMCID: PMC9286709 DOI: 10.1016/s1473-3099(22)00345-0] [Citation(s) in RCA: 169] [Impact Index Per Article: 84.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/05/2022] [Accepted: 05/18/2022] [Indexed: 12/14/2022]
Abstract
Background Hong Kong maintained low circulation of SARS-CoV-2 until a major community epidemic of the omicron (B.1.1.529) sublineage BA.2 began in January, 2022. Both mRNA (BNT162b2 [Fosun Pharma-BioNTech]) and inactivated CoronaVac (Sinovac, Beijing, China) vaccines are widely available; however, vaccination coverage has been low, particularly in older adults aged 70 years or older. We aimed to assess vaccine effectiveness in this predominantly infection-naive population. Methods In this observational study, we used individual-level case data on mild or moderate, severe or fatal, and fatal disease in patients hospitalised with COVID-19 along with census information and coverage data of BNT162b2 and CoronaVac. We used a negative binomial model, adjusting for age, sex, and calendar day to estimate vaccine effectiveness of one, two, and three doses of both BNT162b2 and CoronaVac vaccines, and relative effectiveness by number of doses and vaccine type. Findings Between Dec 31, 2020, and March 16, 2022, 13·2 million vaccine doses were administered in Hong Kong's 7·4-million population. We analysed data from confirmed cases with mild or moderate (n=5566), severe or fatal (n=8875), and fatal (n=6866) COVID-19. Two doses of either vaccine protected against severe disease and death within 28 days of a positive test, with higher effectiveness among adults aged 60 years or older with BNT162b2 (vaccine effectiveness 89·3% [95% CI 86·6–91·6]) compared with CoronaVac (69·9% [64·4–74·6]). Three doses of either vaccine offered very high levels of protection against severe or fatal outcomes (97·9% [97·3–98·4]). Interpretation Third doses of either BNT162b2 or CoronaVac provide substantial additional protection against severe COVID-19 and should be prioritised, particularly in older adults older than 60 years and others in high-risk populations who received CoronaVac primary schedules. Longer follow-up is needed to assess duration of protection across different vaccine platforms and schedules. Funding COVID-19 Vaccines Evaluation Program, Chinese Center for Disease Control and Prevention.
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Affiliation(s)
- Martina E McMenamin
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Joshua Nealon
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
| | - Yun Lin
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Jessica Y Wong
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Justin K Cheung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eric H Y Lau
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China; Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Peng Wu
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China; Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Gabriel M Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China; Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China; Laboratory of Data Discovery for Health, Hong Kong Science and Technology Park, Hong Kong Special Administrative Region, China.
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Xiao J, Cheung JK, Wu P, Ni MY, Cowling BJ, Liao Q. Temporal changes in factors associated with COVID-19 vaccine hesitancy and uptake among adults in Hong Kong: Serial cross-sectional surveys. The Lancet Regional Health - Western Pacific 2022; 23:100441. [PMID: 35359914 PMCID: PMC8961079 DOI: 10.1016/j.lanwpc.2022.100441] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Lin Y, Yang B, Cobey S, Lau EHY, Adam DC, Wong JY, Bond HS, Cheung JK, Ho F, Gao H, Ali ST, Leung NHL, Tsang TK, Wu P, Leung GM, Cowling BJ. Incorporating temporal distribution of population-level viral load enables real-time estimation of COVID-19 transmission. Nat Commun 2022; 13:1155. [PMID: 35241662 PMCID: PMC8894407 DOI: 10.1038/s41467-022-28812-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/14/2022] [Indexed: 12/20/2022] Open
Abstract
Many locations around the world have used real-time estimates of the time-varying effective reproductive number (\documentclass[12pt]{minimal}
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\begin{document}$${R}_{t}$$\end{document}Rt) of COVID-19 to provide evidence of transmission intensity to inform control strategies. Estimates of \documentclass[12pt]{minimal}
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\begin{document}$${R}_{t}$$\end{document}Rt are typically based on statistical models applied to case counts and typically suffer lags of more than a week because of the latent period and reporting delays. Noting that viral loads tend to decline over time since illness onset, analysis of the distribution of viral loads among confirmed cases can provide insights into epidemic trajectory. Here, we analyzed viral load data on confirmed cases during two local epidemics in Hong Kong, identifying a strong correlation between temporal changes in the distribution of viral loads (measured by RT-qPCR cycle threshold values) and estimates of \documentclass[12pt]{minimal}
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\begin{document}$${R}_{t}$$\end{document}Rt based on case counts. We demonstrate that cycle threshold values could be used to improve real-time \documentclass[12pt]{minimal}
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\begin{document}$${R}_{t}$$\end{document}Rt estimation, enabling more timely tracking of epidemic dynamics. The time-varying effective reproductive number (Rt) is useful for monitoring transmission of infections such as COVID-19, but reporting delays impact case count-based estimation methods. Here, the authors demonstrate and validate a method for estimation of Rt based on viral load data from Hong Kong that does not require accurate daily counts.
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Affiliation(s)
- Yun Lin
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Bingyi Yang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sarah Cobey
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| | - Eric H Y Lau
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China
| | - Dillon C Adam
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Jessica Y Wong
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Helen S Bond
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Justin K Cheung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Faith Ho
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Huizhi Gao
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sheikh Taslim Ali
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China
| | - Nancy H L Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Tim K Tsang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China
| | - Peng Wu
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China
| | - Gabriel M Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. .,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong, China.
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Neves-Pereira M, Cheung JK, Pasdar A, Zhang F, Breen G, Yates P, Sinclair M, Crombie C, Walker N, St Clair DM. BDNF gene is a risk factor for schizophrenia in a Scottish population. Mol Psychiatry 2005; 10:208-12. [PMID: 15630410 DOI: 10.1038/sj.mp.4001575] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Schizophrenia is a severe psychiatric disease with a strong genetic component. Brain-derived neurotrophic factor (BDNF) has been implicated in the pathogenesis of schizophrenia and bipolar (BP) disorders. The present study has examined two polymorphisms in linkage disequilibrium in the BDNF gene, which have been variously reported as associated with schizophrenia and BP. In our study, 321 probands with a primary diagnosis of schizophrenia or schizoaffective disorder, and 263 with a diagnosis of bipolar affective disorder, were examined together with 350 controls drawn from the same geographical region of Scotland. The val66met single-nucleotide polymorphism (SNP) showed significant (P = 0.005) association for valine (allele G) with schizophrenia but not bipolar disorder. Haplotype analysis of val/met SNP and a dinucleotide repeat polymorphism in the putative promoter region revealed highly significant (P < 1 x 10(-8)) under-representation of the methionine or met-1 haplotype in the schizophrenic but not the BP population. We conclude that, although the val66met polymorphism has been reported to alter gene function, the risk may depend upon the haplotypic background on which the val/met variant is carried.
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Affiliation(s)
- M Neves-Pereira
- Department of Mental Health, University of Aberdeen, Institute of Medical Science, Aberdeen, Scotland AB25 2ZD, UK
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Cheung JK, Rood JI. The VirR response regulator from Clostridium perfringens binds independently to two imperfect direct repeats located upstream of the pfoA promoter. J Bacteriol 2000; 182:57-66. [PMID: 10613863 PMCID: PMC94240 DOI: 10.1128/jb.182.1.57-66.2000] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regulation of toxin production in the gram-positive anaerobe Clostridium perfringens occurs at the level of transcription and involves a two-component signal transduction system. The sensor histidine kinase is encoded by the virS gene, while its cognate response regulator is encoded by the virR gene. We have constructed a VirR expression plasmid in Escherichia coli and purified the resultant His-tagged VirR protein. Gel mobility shift assays demonstrated that VirR binds to the region upstream of the pfoA gene, which encodes perfringolysin O, but not to regions located upstream of the VirR-regulated plc, colA, and pfoR genes, which encode alpha-toxin, collagenase, and a putative pfoA regulator, respectively. The VirR binding site was shown by DNase I footprinting to be a 52-bp core sequence situated immediately upstream of the pfoA promoter. When this region was deleted, VirR was no longer able to bind to the pfoA promoter. The binding site was further localized to two imperfect direct repeats (CCCAGTTNTNCAC) by site-directed mutagenesis. Binding and protection analysis of these mutants indicated that VirR had the ability to bind independently to the two repeated sequences. Based on these observations it is postulated that the VirR positively regulates the synthesis of perfringolysin O by binding directly to a region located immediately upstream of the pfoA promoter and activating transcription.
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Affiliation(s)
- J K Cheung
- Bacterial Pathogenesis Research Group, Department of Microbiology, Monash University, Clayton 3800, Australia
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Masur SK, Conors RJ, Cheung JK, Antohi S. Matrix adhesion characteristics of corneal myofibroblasts. Invest Ophthalmol Vis Sci 1999; 40:904-10. [PMID: 10102287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
PURPOSE To investigate the adhesion characteristics of corneal myofibroblasts in a cell culture model. METHODS Immunocytochemistry, immunoprecipitation, western blot analysis, and attachment assays were used to evaluate matrix adhesion characteristics of myofibroblasts. RESULTS Myofibroblasts, defined by their expression of the smooth muscle isoform of alpha-actin, were evaluated and compared with fibroblasts. Myofibroblasts had larger vinculin-containing focal adhesions and expressed more of the classic fibronectin receptor (FNR) alpha5beta1 per cell. However, myofibroblasts had less surface expression of the higher molecular weight alpha4 subunit of another FNR, alpha4beta1, than did fibroblasts. Myofibroblasts adhered more avidly in an integrin-dependent manner to fibronectin than did fibroblasts. The attachment to fibronectin was actin-dependent for both phenotypes, but the myofibroblasts' adhesion was more resistant to disruption by cytochalasin than were fibroblasts'. In addition to the previously described expression of a 135-kDa classic cadherin, myofibroblasts also expressed a 115-kDa mesenchymal cadherin, cadherin-11. CONCLUSIONS Differentiation of corneal fibroblasts into myofibroblasts is associated with characteristics that would indicate that the latter have a special role in wound closure. The increase in focal and cell adhesion molecules that accompanies smooth muscle-specific actin expression provides the basis for the myofibroblasts' enhanced cell-fibronectin and cell-cell adhesion.
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Affiliation(s)
- S K Masur
- Department of Ophthalmology, Mount Sinai School of Medicine of the City University of New York, NY 10029-6574, USA
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Billington SJ, Huggins AS, Johanesen PA, Crellin PK, Cheung JK, Katz ME, Wright CL, Haring V, Rood JI. Complete nucleotide sequence of the 27-kilobase virulence related locus (vrl) of Dichelobacter nodosus: evidence for extrachromosomal origin. Infect Immun 1999; 67:1277-86. [PMID: 10024571 PMCID: PMC96457 DOI: 10.1128/iai.67.3.1277-1286.1999] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The vrl locus is preferentially associated with virulent isolates of the ovine footrot pathogen, Dichelobacter nodosus. The complete nucleotide sequence of this 27.1-kb region has now been determined. The data reveal that the locus has a G+C content much higher than the rest of the D. nodosus chromosome and contains 22 open reading frames (ORFs) encoding products including a putative adenine-specific methylase, two potential DEAH ATP-dependent helicases, and two products with sequence similarity to a bacteriophage resistance system. These ORFs are all in the same orientation, and most are either overlapping or separated by only a few nucleotides, suggesting that they comprise an operon and are translationally coupled. Expression vector studies have led to the identification of proteins that correspond to many of these ORFs. These data, in combination with evidence of insertion of vrl into the 3' end of an ssrA gene, are consistent with the hypothesis that the vrl locus was derived from the insertion of a bacteriophage or plasmid into the D. nodosus genome.
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Affiliation(s)
- S J Billington
- Department of Microbiology, Monash University, Clayton, Victoria 3168, Australia
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Masur SK, Cheung JK, Antohi S. Identification of integrins in cultured corneal fibroblasts and in isolated keratocytes. Invest Ophthalmol Vis Sci 1993; 34:2690-8. [PMID: 8344791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE The integrins are a family of transmembrane glycoproteins that function in attachment of cells to one another and to the extracellular matrix. When cell--cell and cell--matrix interactions are altered, the population of integrins may change. In particular, removing cells from their normal environment may be used as a model of wounding. The current study reports the identification of the integrins expressed at the cell surface of noncultured keratocytes and of cultured corneal fibroblasts, which are derived from keratocytes grown in primary culture. METHODS For integrin identification, the surface proteins of keratocytes and cultured corneal fibroblasts were labeled with biotin, and the integrins were immunoprecipitated using anti-integrin antibodies. Attachment assays determined (1) the extracellular matrix preference of the cultured corneal fibroblasts and (2) the effects of function-perturbing antibodies against the fibronectin receptor (alpha 5 beta 1) or against other beta 1-containing integrins. RESULTS The integrins of noncultured keratocytes were present as heterodimeric alpha, beta surface proteins that were immunoprecipitated by anti-beta 1, anti-alpha v, anti-alpha 6, anti-alpha 3, anti-alpha 1, and anti-beta 3. Furthermore, when the keratocytes were placed in culture, the integrin pattern changed. The classic fibronectin receptor, alpha 5 beta 1, is then expressed along with additional integrins that bind to fibronectin. Using attachment assays, we determined that the cultured corneal fibroblasts prefer fibronectin to collagen, vitronectin, or laminin as extracellular matrix substrate. In addition, function-perturbing antibodies against the fibronectin receptor (alpha 5 beta 1) or against beta 1 inhibit attachment of cultured corneal fibroblasts to fibronectin. CONCLUSIONS Receptors for fibronectin and other extracellular matrix molecules are expressed at the cell surface in cultured corneal fibroblasts, and are in position to play a significant functional role as seen in attachment to extracellular matrix.
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Affiliation(s)
- S K Masur
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York 10029-6574
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