24 results on '"Chen, Mi"'
Search Results
2. Farnesoid X receptor via Notch1 directs asymmetric cell division of Sox9+ cells to prevent the development of liver cancer in a mouse model
- Author
-
Chen, Mi, Lu, Chenxia, Lu, Hanwen, Zhang, Junyi, Qin, Dan, Liu, Shenghui, Li, Xiaodong, and Zhang, Lisheng
- Published
- 2021
- Full Text
- View/download PDF
3. Dendrobium nobile Lindley and its bibenzyl component moscatilin are able to protect retinal cells from ischemia/hypoxia by dowregulating placental growth factor and upregulating Norrie disease protein
- Author
-
Chao, Wen-Haur, Lai, Ming-Yi, Pan, Hwai-Tzong, Shiu, Huei-Wen, Chen, Mi-Mi, and Chao, Hsiao-Ming
- Published
- 2018
- Full Text
- View/download PDF
4. Prevalence of measles antibodies among migrant workers in Singapore: a serological study to identify susceptible population subgroups.
- Author
-
Ang LW, Gao Q, Cui L, Farwin A, Toh MPHS, Boudville IC, Chen MI, Chow A, Lin RT, Lee VJM, and Leo YS
- Subjects
- Antibodies, Viral, Female, Humans, Male, Middle Aged, Prevalence, Seroepidemiologic Studies, Singapore epidemiology, Measles epidemiology, Transients and Migrants
- Abstract
Background: In 2019, two clusters of measles cases were reported in migrant worker dormitories in Singapore. We conducted a seroprevalence study to measure the level of susceptibility to measles among migrant workers in Singapore., Methods: Our study involved residual sera of migrant workers from seven Asian countries (Bangladesh, China, India, Indonesia, Malaysia, Myanmar and the Philippines) who had participated in a survey between 2016 and 2019. Immunoglobulin G (IgG) antibody levels were first measured using a commercial enzyme-linked immunosorbent assay (ELISA) test kit. Those with equivocal or negative IgG results were further evaluated using plaque reduction neutralization test (PRNT)., Results: A total of 2234 migrant workers aged 20-49 years were included in the study. The overall prevalence of measles IgG antibodies among migrant workers from the seven Asian countries was 90.5% (95% confidence interval 89.2-91.6%). The country-specific seroprevalence ranged from 80.3 to 94.0%. The seroprevalence was significantly higher among migrant workers born in 1965-1989 than those born in 1990-1999 (95.3% vs. 86.6%, p < 0.0005), whereas there was no significant difference by gender (90.8% in men vs. 89.9% in women, p = 0.508). 195 out of 213 samples with equivocal or negative ELISA results were tested positive using PRNT., Conclusion: The IgG seroprevalence in migrant workers was below the herd immunity threshold of 95% for measles. Sporadic outbreaks may occur in susceptible individuals due to high transmissibility of measles virus. Seroprevalence surveys can help identify susceptible subgroups for vaccination., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
5. Seroprevalence of IgG antibodies against diphtheria antitoxin among migrant workers in Singapore, 2016-2019.
- Author
-
Ang LW, Gao Q, Cui L, Farwin A, Toh MPHS, Boudville IC, Chen MI, Chow A, Lin RT, Lee VJM, and Leo YS
- Subjects
- Adult, Antibodies, Bacterial, Diphtheria Antitoxin, Diphtheria Toxoid, Humans, Immunoglobulin G, Seroepidemiologic Studies, Singapore epidemiology, Diphtheria epidemiology, Diphtheria prevention & control, Transients and Migrants
- Abstract
Background: Since the last local case of diphtheria in 1992, there had not been any case in Singapore until an autochthonous case was reported in 2017. This fatal diphtheria case of a migrant worker raised concerns about the potential re-emergence of locally transmitted toxigenic diphtheria in Singapore. We conducted a seroprevalence study to assess the immunity levels to diphtheria among migrant workers in Singapore., Methods: Residual sera from migrant workers who hailed from Bangladesh, China, India, Indonesia, Malaysia, Myanmar and the Philippines were tested for anti-diphtheria toxoid immunoglobulin G (IgG) antibodies. These migrant workers previously participated in a survey between 2016 and 2019 and had provided blood samples as part of the survey procedure., Results: A total of 2176 migrant workers were included in the study. Their overall mean age was 27.1 years (standard deviation 5.0), range was 20-43 years. The proportion having at least basic protection against diphtheria (antitoxin titres ≥ 0.01 IU/ml) ranged from 77.9% (95% confidence interval [CI] 72.8 - 82.3%) among migrant workers from Bangladesh to 96.7% (95% CI 92.5 - 98.6%) in those hailing from Malaysia. The proportion showing full protection (antitoxin titres ≥ 0.10 IU/ml) ranged from 10.1% (95% CI 6.5 - 15.4%) in Chinese workers to 23.0% (95% CI 17.1 - 30.3%) in Malaysian workers. There were no significant differences in the proportion with at least basic protection across birth cohorts, except for those from Bangladesh where the seroprevalence was significantly lower in younger migrant workers born after 1989., Conclusions: The proportions having at least basic protection against diphtheria in migrant workers from five out of seven Asian countries (India, Indonesia, Malaysia, Myanmar and the Philippines) were higher than 85%, the threshold for diphtheria herd immunity. Seroprevalence surveys should be conducted periodically to assess the level of immunity against diphtheria and other vaccine preventable diseases in migrant worker population, so that appropriate interventions such as booster vaccination can be implemented proactively to prevent sporadic outbreaks., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
6. Adequacy of public health communications on H7N9 and MERS in Singapore: insights from a community based cross-sectional study.
- Author
-
Hou Y, Tan YR, Lim WY, Lee V, Tan LWL, Chen MI, and Yap P
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Radio, Singapore epidemiology, Socioeconomic Factors, Television, Young Adult, Coronavirus Infections epidemiology, Disease Outbreaks, Health Communication standards, Health Knowledge, Attitudes, Practice, Influenza A Virus, H7N9 Subtype, Influenza, Human epidemiology, Public Health
- Abstract
Background: Singapore remains vulnerable to worldwide epidemics due to high air traffic with other countries This study aims to measure the public's awareness of the Middle East Respiratory Syndrome (MERS) and Avian Influenza A (H7N9), identify population groups who are uninformed or misinformed about the diseases, understand their choice of outbreak information source, and assess the effectiveness of communication channels in Singapore., Methods: A cross-sectional study, comprising of face-to-face interviews, was conducted between June and December 2013 to assess the public's awareness and knowledge of MERS and H7N9, including their choice of information source. Respondents were randomly selected and recruited from 3 existing cohort studies. An opportunistic sampling approach was also used to recruit new participants or members in the same household through referrals from existing participants., Results: Out of 2969 participants, 53.2% and 79.4% were not aware of H7N9 and MERS respectively. Participants who were older and better educated were most likely to hear about the diseases. The mean total knowledge score was 9.2 (S.D ± 2.3) out of 20, and 5.9 (S.D ± 1.2) out of 10 for H7N9 and MERS respectively. Participants who were Chinese, more educated and older had better knowledge of the diseases. Television and radio were the primary sources of outbreak information regardless of socio-demographic factors., Conclusion: Heightening education of infectious outbreaks through appropriate media to the young and less educated could increase awareness.
- Published
- 2018
- Full Text
- View/download PDF
7. Using peer review to distribute group work marks equitably between medical students.
- Author
-
Cook AR, Hartman M, Luo N, Sng J, Fong NP, Lim WY, Chen MI, Wong ML, Rajaraman N, Lee JJ, and Koh GC
- Subjects
- Humans, Models, Theoretical, Motivation, Peer Review, Program Evaluation, Clinical Competence standards, Education, Medical, Undergraduate, Educational Measurement methods, Students, Medical
- Abstract
Background: Although peer assessment has been used for evaluating performance of medical students and practicing doctors, it has not been studied as a method to distribute a common group work mark equitably to medical students working in large groups where tutors cannot observe all students constantly., Methods: The authors developed and evaluated a mathematical formulation whereby a common group mark could be distributed among group members using peer assessment of individual contributions to group work, maintaining inter-group variation in group work scores. This was motivated by community health projects undertaken by large groups of year four medical students at the National University of Singapore, and the new and old formulations are presented via application to 263 students in seven groups of 36 to 40 during the academic year 2012/2013., Results: This novel formulation produced a less clustered mark distribution that rewarded students who contributed more to their team. Although collusion among some members to form a voting alliance and 'personal vendettas' were potential problems, the former was not detected and the latter had little impact on the overall grade a student received when working in a large group. The majority of students thought the new formulation was fairer., Conclusions: The new formulation is easy to implement and arguably awards grades more equitably in modules where group work is a major component.
- Published
- 2017
- Full Text
- View/download PDF
8. Mapping infectious disease hospital surge threats to lessons learnt in Singapore: a systems analysis and development of a framework to inform how to DECIDE on planning and response strategies.
- Author
-
Singh SR, Coker R, Vrijhoef HJ, Leo YS, Chow A, Lim PL, Tan Q, Chen MI, and Hildon ZJ
- Subjects
- Clinical Decision-Making methods, Crowding, Disaster Planning methods, Emergency Service, Hospital statistics & numerical data, Humans, Medical Staff, Hospital statistics & numerical data, Personnel Staffing and Scheduling statistics & numerical data, Public Health, Singapore, Systems Analysis, Disease Outbreaks prevention & control, Hospitalization statistics & numerical data, Infection Control methods
- Abstract
Background: Hospital usage and service demand during an Infectious Disease (ID) outbreak can tax the health system in different ways. Herein we conceptualize hospital surge elements, and lessons learnt from such events, to help build appropriately matched responses to future ID surge threats., Methods: We used the Interpretive Descriptive qualitative approach. Interviews (n = 35) were conducted with governance and public health specialists; hospital based staff; and General Practitioners. Key policy literature in tandem with the interview data were used to iteratively generate a Hospital ID Surge framework. We anchored our narrative account within this framework, which is used to structure our analysis., Results: A spectrum of surge threats from combinations of capacity (for crowding) and capability (for treatment complexity) demands were identified. Starting with the Pyramid scenario, or an influx of high screening rates flooding Emergency Departments, alongside fewer and manageable admissions; the Reverse-Pyramid occurs when few cases are screened and admitted but those that are, are complex; during a 'Black' scenario, the system is overburdened by both crowding and complexity. The Singapore hospital system is highly adapted to crowding, functioning remarkably well at constant near-full capacity in Peacetime and resilient to Endemic surges. We catalogue 26 strategies from lessons learnt relating to staffing, space, supplies and systems, crystalizing institutional memory. The DECIDE model advocates linking these strategies to types of surge threats and offers a step-by-step guide for coordinating outbreak planning and response., Conclusions: Lack of a shared definition and decision making of surge threats had rendered the procedures somewhat duplicative. This burden was paradoxically exacerbated by a health system that highly prizes planning and forward thinking, but worked largely in silo until an ID crisis hit. Many such lessons can be put into play to further strengthen our current hospital governance and adapted to more diverse settings.
- Published
- 2017
- Full Text
- View/download PDF
9. The immune response to 6-monthly versus annual standard dose inactivated trivalent influenza vaccination in older people: study protocol for a randomised clinical trial.
- Author
-
Young B, Sadarangani S, Yew HS, Yung CF, Leo YS, Chen MI, and Wilder-Smith A
- Subjects
- Age Factors, Aged, Antibodies, Viral blood, Clinical Protocols, Female, Hemagglutination Inhibition Tests, Humans, Immunity, Cellular drug effects, Influenza Vaccines adverse effects, Influenza Vaccines immunology, Influenza, Human diagnosis, Influenza, Human immunology, Influenza, Human virology, Male, Research Design, Singapore, Time Factors, Treatment Outcome, Immunization Schedule, Immunogenicity, Vaccine, Influenza Vaccines administration & dosage, Influenza, Human prevention & control, Vaccination
- Abstract
Background: The seasonal influenza vaccine is less effective in older people and a single dose is unlikely to provide the year-round protection necessary for tropical climates which have year-round influenza virus activity. This study aims to assess the effect of a trivalent inactivated influenza vaccine (IIV3) booster at 180 days on haemagglutination-inhibition (HI) antibody titres for each of the influenza strains present in the administered vaccine in older people aged 65 years or above in Singapore., Methods/design: This is a single-centre, randomised, observer-blind, active-comparator controlled, parallel-group, phase IV trial in 200 adults aged 65 years or older. Study participants will be assigned to one of two groups in a 1:1 ratio and followed for 1 year, with five scheduled visits. The control group will receive IIV3 at day 1, and an active comparator (Tetanus-diphtheria-pertussis vaccine) at day 180. Participants in the experimental group will receive IIV3 containing the same strains at day 1 and day 180. Endpoints are immunological, and include measures of HI titres, microneutralisation titres (MN) and cell-mediated immunity from first vaccination up to day 360., Discussion: If superiority of 6-monthly influenza vaccination is demonstrated, this study could form the basis for a larger clinical trial with influenza infection as the primary endpoint., Trial Registration: ClinicalTrials.gov, ID: NCT02655874 . Registered on 12 January 2016.
- Published
- 2017
- Full Text
- View/download PDF
10. Knowledge, attitudes and practices towards antibiotic use in upper respiratory tract infections among patients seeking primary health care in Singapore.
- Author
-
Pan DS, Huang JH, Lee MH, Yu Y, Chen MI, Goh EH, Jiang L, Chong JW, Leo YS, Lee TH, Wong CS, Loh VW, Poh AZ, Tham TY, Wong WM, and Lim FS
- Subjects
- Adult, Aged, Cross-Sectional Studies, Educational Status, Female, Fever virology, Humans, Malaysia ethnology, Male, Middle Aged, Patient Acceptance of Health Care ethnology, Pharyngitis virology, Residence Characteristics, Respiratory Tract Infections complications, Respiratory Tract Infections virology, Singapore, Surveys and Questionnaires, Young Adult, Anti-Bacterial Agents therapeutic use, Health Knowledge, Attitudes, Practice ethnology, Primary Health Care, Respiratory Tract Infections drug therapy
- Abstract
Background: Patients' expectations can influence antibiotic prescription by primary healthcare physicians. We assessed knowledge, attitude and practices towards antibiotic use for upper respiratory tract infections (URTIs), and whether knowledge is associated with increased expectations for antibiotics among patients visiting primary healthcare services in Singapore., Methods: Data was collected through a cross-sectional interviewer-assisted survey of patients aged ≥21 years waiting to see primary healthcare practitioners for one or more symptoms suggestive of URTI (cough, sore throat, runny nose or blocked nose) for 7 days or less, covering the demographics, presenting symptoms, knowledge, attitudes, beliefs and practices of URTI and associated antibiotic use. Univariate and multivariate logistic regression was used to assess independent factors associated with patients' expectations for antibiotics., Results: Nine hundred fourteen out of 987 eligible patients consulting 35 doctors were recruited from 24 private sector primary care clinics in Singapore. A third (307/907) expected antibiotics, of which a substantial proportion would ask the doctor for antibiotics (121/304, 40 %) and/or see another doctor (31/304, 10 %) if antibiotics were not prescribed. The majority agreed "antibiotics are effective against viruses" (715/914, 78 %) and that "antibiotics cure URTI faster" (594/912, 65 %). Inappropriate antibiotic practices include "keeping antibiotics stock at home" (125/913, 12 %), "taking leftover antibiotics" (114/913, 14 %) and giving antibiotics to family members (62/913, 7 %). On multivariate regression, the following factors were independently associated with wanting antibiotics (odds ratio; 95 % confidence interval): Malay ethnicity (1.67; 1.00-2.79), living in private housing (1.69; 1.13-2.51), presence of sore throat (1.50; 1.07-2.10) or fever (1.46; 1.01-2.12), perception that illness is serious (1.70; 1.27-2.27), belief that antibiotics cure URTI faster (5.35; 3.76-7.62) and not knowing URTI resolves on its own (2.18; 1.08-2.06), while post-secondary education (0.67; 0.48-0.94) was inversely associated. Those with lower educational levels were significantly more likely to have multiple misconceptions about antibiotics., Conclusion: Majority of patients seeking primary health care in Singapore are misinformed about the role of antibiotics in URTI. Agreeing with the statement that antibiotics cure URTI faster was most strongly associated with wanting antibiotics. Those with higher educational levels were less likely to want antibiotics, while those with lower educational levels more likely to have incorrect knowledge.
- Published
- 2016
- Full Text
- View/download PDF
11. Risk factors for febrile respiratory illness and mono-viral infections in a semi-closed military environment: a case-control study.
- Author
-
Pang J, Jin J, Loh JP, Tan BH, Koh WH, Ng SH, Ho ZJ, Gao Q, Cook AR, Hsu LY, Lee VJ, and Chen MI
- Subjects
- Adenoviridae isolation & purification, Adolescent, Adult, Case-Control Studies, Enterovirus isolation & purification, Environment, Female, Humans, Influenza A virus isolation & purification, Influenza B virus isolation & purification, Influenza, Human epidemiology, Influenza, Human transmission, Influenza, Human virology, Logistic Models, Male, Middle Aged, Rhinovirus isolation & purification, Risk Factors, Singapore epidemiology, Surveys and Questionnaires, Virus Diseases transmission, Virus Diseases virology, Young Adult, Military Personnel, Virus Diseases epidemiology
- Abstract
Background: Febrile respiratory illness (FRI) results in substantial burden in semi-closed environments. Tackling risk factors may reduce transmission and infection. However, risk factors involved in one setting may not be generalizable in all settings due to differences in climate, residential environment, population genetic and cultural backgrounds. This study aims to identify risk factors of FRI and mono-viral infections in a tropical military environment., Methods: From year 2009 to 2012, military personnel with temperature ≥37.5 °C, cough and/or sore throat, and personnel with no fever or no respiratory symptoms were recruited as cases and controls, respectively. Subjects provided nasal wash specimens and answered a standardized questionnaire. Resplex assays were used to determine the viral etiologies. Descriptive, univariate and multivariate analyses of the variables were performed using appropriate descriptive tests and logistic regression modelling, respectively, with R program., Results: A total of 7,743 FRI cases and 1,247 non-FRI study controls were recruited. Increasing age [adjusted odds ratio (AOR) = 1.03; 95 % confidence interval (CI) = 1.01-1.05], recruit camp (AOR = 4.67; 95 % CI = 3.99-5.46) and smoker (AOR = 1.31; 95 % CI = 1.13-1.52) were independent risk factors of FRI. Malay ethnicity was positively associated with influenza A(H1N1)pdm09 (AOR = 1.50; 95 % CI = 1.04-2.15) and coxsackie/echovirus (AOR = 1.67; 95 % CI = 1.19-2.36) mono-infection. Significant contact risk factors were stay-out personnel with ill household member (AOR = 4.96; 95 % CI = 3.39-7.24), and stay-in personnel with ill bunkmate and household member (AOR = 3.55; 95 % CI = 2.57-4.91). Staying in camp with none ill in bunk and at home was a protective factor against FRI (AOR = 0.80; 95 % CI = 0.64-0.99). These contact risk factors were similarly observed for the five most common viruses detected, namely adenovirus, rhinoviruses, influenza A and B, and coxsackie/echovirus., Conclusion: Increasing age, smoker, recruit-camp, stay-out personnel with ill household members and stay-in personnel with ill bunkmates were independent risk factors of FRI in a semi-closed military environment. Early identification and isolation of ill personnel from their bunk may be effective to prevent and reduce transmission and disease burden.
- Published
- 2015
- Full Text
- View/download PDF
12. Rate of decline of antibody titers to pandemic influenza A (H1N1-2009) by hemagglutination inhibition and virus microneutralization assays in a cohort of seroconverting adults in Singapore.
- Author
-
Hsu JP, Zhao X, Chen MI, Cook AR, Lee V, Lim WY, Tan L, Barr IG, Jiang L, Tan CL, Phoon MC, Cui L, Lin R, Leo YS, and Chow VT
- Subjects
- Adult, Aged, Cohort Studies, Female, Hemagglutination Inhibition Tests, Humans, Influenza A Virus, H1N1 Subtype isolation & purification, Influenza, Human epidemiology, Influenza, Human virology, Male, Middle Aged, Neutralization Tests, Singapore epidemiology, Vaccination methods, Young Adult, Antibodies, Viral immunology, Influenza A Virus, H1N1 Subtype immunology, Influenza, Human immunology
- Abstract
Background: The rate of decline of antibody titers to influenza following infection can affect results of serological surveys, and may explain re-infection and recurrent epidemics by the same strain., Methods: We followed up a cohort who seroconverted on hemagglutination inhibition (HI) antibody titers (≥ 4-fold increase) to pandemic influenza A(H1N1)pdm09 during a seroincidence study in 2009. Along with the pre-epidemic sample, and the sample from 2009 with the highest HI titer between August and October 2009 (A), two additional blood samples obtained in April 2010 and September 2010 (B and C) were assayed for antibodies to A(H1N1)pdm09 by both HI and virus microneutralization (MN) assays. We analyzed pair-wise mean-fold change in titers and the proportion with HI titers ≥ 40 and MN ≥ 160 (which correlated with a HI titer of 40 in our assays) at the 3 time-points following seroconversion., Results: A total of 67 participants contributed 3 samples each. From the highest HI titer in 2009 to the last sample in 2010, 2 participants showed increase in titers (by HI and MN), while 63 (94%) and 49 (73%) had reduction in HI and MN titers, respectively. Titers by both assays decreased significantly; while 70.8% and 72.3% of subjects had titers of ≥ 40 and 160 by HI and MN in 2009, these percentages decreased to 13.9% and 36.9% by September 2010. In 6 participants aged 55 years and older, the decrease was significantly greater than in those aged below 55, so that none of the elderly had HI titers ≥ 40 nor MN titers ≥ 160 by the final sample. Due to this decline in titers, only 23 (35%) of the 65 participants who seroconverted on HI in sample A were found to seroconvert between the pre-epidemic sample and sample C, compared to 53 (90%) of the 59 who seroconverted on MN on Sample A., Conclusions: We observed marked reduction in titers 1 year after seroconversion by HI, and to a lesser extent by MN. Our findings have implications for re-infections, recurrent epidemics, vaccination strategies, and for cohort studies measuring infection rates by seroconversion.
- Published
- 2014
- Full Text
- View/download PDF
13. Health-seeking behaviour of male foreign migrant workers living in a dormitory in Singapore.
- Author
-
Lee W, Neo A, Tan S, Cook AR, Wong ML, Tan J, Sayampanathan A, Lim D, Tang SY, Goh WL, Chen MI, and Ho C
- Subjects
- Adult, Bangladesh ethnology, Cross-Sectional Studies, Housing, Humans, India ethnology, Male, Myanmar ethnology, Singapore, Surveys and Questionnaires, Patient Acceptance of Health Care, Transients and Migrants
- Abstract
Background: Foreign workers' migrant status may hinder their utilisation of health services. This study describes the health-seeking behaviour and beliefs of a group of male migrant workers in Singapore and the barriers limiting their access to primary healthcare., Methods: A cross-sectional study of 525 male migrant workers, ≥ 21 years old and of Indian, Bangladeshi or Myanmar nationality, was conducted at a dormitory via self-administered questionnaires covering demographics, prevalence of medical conditions and health-seeking behaviours through hypothetical scenarios and personal experience., Results: 71% (95%CI: 67 to 75%) of participants did not have or were not aware if they had healthcare insurance. 53% (95%CI: 48 to 57%) reported ever having had an illness episode while in Singapore, of whom 87% (95%CI: 82 to 91%) saw a doctor. The number of rest days was significantly associated with higher probability of having consulted a doctor for their last illness episode (p = 0.026), and higher basic monthly salary was associated with seeing a doctor within 3 days of illness (p = 0.002). Of those who saw a doctor, 84% (95%CI: 79 to 89%) responded that they did so because they felt medical care would help them to work better. While 55% (95%CI: 36 to 73%) said they did not see a doctor because the illness was not serious, those with lower salaries were significantly more likely to cite inadequate finances (55% of those earning < S$500/month). In hypothetical injury or illness scenarios, most responded that they would see the doctor, but a sizeable proportion (15% 95%CI: 12 to 18%) said they would continue to work even in a work-related injury scenario that caused severe pain and functional impairment. Those with lower salaries were significantly more likely to believe they would have to pay for their own healthcare or be uncertain about who would pay., Conclusions: The majority of foreign workers in this study sought healthcare when they fell ill. However, knowledge about health-related insurance was poor and a sizeable minority, in particular those earning < S$500 per month, may face significant issues in accessing care.
- Published
- 2014
- Full Text
- View/download PDF
14. Respiratory viral pathogens among Singapore military servicemen 2009-2012: epidemiology and clinical characteristics.
- Author
-
Tan XQ, Zhao X, Lee VJ, Loh JP, Tan BH, Koh WH, Ng SH, Chen MI, and Cook AR
- Subjects
- Adult, Female, Humans, Influenza Vaccines, Influenza, Human diagnosis, Influenza, Human epidemiology, Influenza, Human prevention & control, Influenza, Human virology, Logistic Models, Male, Prevalence, Sensitivity and Specificity, Sentinel Surveillance, Singapore epidemiology, Virus Diseases diagnosis, Virus Diseases virology, Military Personnel, Virus Diseases epidemiology
- Abstract
Background: Few studies have comprehensively described tropical respiratory disease surveillance in military populations. There is also a lack of studies comparing clinical characteristics of the non-influenza pathogens with influenza and amongst themselves., Methods: From May 2009 through October 2012, 7733 consenting cases of febrile respiratory illness (FRI) (temperature [greater than or equal to]37.5 degrees C with cough or sorethroat) and controls in the Singapore military had clinical data and nasal washes collected prospectively. Nasal washes underwent multiplex PCR, and the analysis was limited to viral mono-infections., Results: 49% of cases tested positive for at least one virus, of whom 10% had multiple infections. 53% of the FRI cases fulfilled the definition of influenza-like illness (ILI), of whom 52% were positive for at least one virus. The most frequent etiologies for mono-infections among FRI cases were Influenza A(H1N1)pdm09 (13%), Influenza B (13%) and coxsackevirus (9%). The sensitivity, specificity, positive predictive value and negative predictive value of ILI for influenza among FRI cases were 72%, 48%, 40% and 69% respectively. On logistic regression, there were marked differences in the prevalence of different symptoms and signs between viruses with fever more prevalent amongst influenza and adenovirus infections than other viruses., Conclusion: There are multiple viral etiologies for FRI and ILI with differing clinical symptoms in the Singapore military. Influenza and coxsackevirus were the most common etiology for FRI, while influenza and adenoviruses displayed the most febrile symptoms. Further studies should explore these differences and possible interventions.
- Published
- 2014
- Full Text
- View/download PDF
15. Trends in parameterization, economics and host behaviour in influenza pandemic modelling: a review and reporting protocol.
- Author
-
Carrasco LR, Jit M, Chen MI, Lee VJ, Milne GJ, and Cook AR
- Abstract
Background: The volume of influenza pandemic modelling studies has increased dramatically in the last decade. Many models incorporate now sophisticated parameterization and validation techniques, economic analyses and the behaviour of individuals., Methods: We reviewed trends in these aspects in models for influenza pandemic preparedness that aimed to generate policy insights for epidemic management and were published from 2000 to September 2011, i.e. before and after the 2009 pandemic., Results: We find that many influenza pandemics models rely on parameters from previous modelling studies, models are rarely validated using observed data and are seldom applied to low-income countries. Mechanisms for international data sharing would be necessary to facilitate a wider adoption of model validation. The variety of modelling decisions makes it difficult to compare and evaluate models systematically., Conclusions: We propose a model Characteristics, Construction, Parameterization and Validation aspects protocol (CCPV protocol) to contribute to the systematisation of the reporting of models with an emphasis on the incorporation of economic aspects and host behaviour. Model reporting, as already exists in many other fields of modelling, would increase confidence in model results, and transparency in their assessment and comparison.
- Published
- 2013
- Full Text
- View/download PDF
16. Teacher led school-based surveillance can allow accurate tracking of emerging infectious diseases - evidence from serial cross-sectional surveys of febrile respiratory illness during the H1N1 2009 influenza pandemic in Singapore.
- Author
-
Soh SE, Cook AR, Chen MI, Lee VJ, Cutter JL, Chow VT, Tee NW, Lin RT, Lim WY, Barr IG, Lin C, Phoon MC, Ang LW, Sethi SK, Chong CY, Goh LG, Goh DL, Tambyah PA, Thoon KC, Leo YS, and Saw SM
- Subjects
- Cross-Sectional Studies, Fever of Unknown Origin epidemiology, Humans, Incidence, Influenza A Virus, H1N1 Subtype isolation & purification, Influenza, Human epidemiology, Influenza, Human virology, Schools, Singapore epidemiology, Communicable Diseases, Emerging epidemiology, Epidemiologic Methods, Faculty
- Abstract
Background: Schools are important foci of influenza transmission and potential targets for surveillance and interventions. We compared several school-based influenza monitoring systems with clinic-based influenza-like illness (ILI) surveillance, and assessed the variation in illness rates between and within schools., Methods: During the initial wave of pandemic H1N1 (pdmH1N1) infections from June to Sept 2009 in Singapore, we collected data on nation-wide laboratory confirmed cases (Sch-LCC) and daily temperature monitoring (Sch-DTM), and teacher-led febrile respiratory illness reporting in 6 sentinel schools (Sch-FRI). Comparisons were made against age-stratified clinic-based influenza-like illness (ILI) data from 23 primary care clinics (GP-ILI) and proportions of ILI testing positive for pdmH1N1 (Lab-ILI) by computing the fraction of cumulative incidence occurring by epidemiological week 30 (when GP-ILI incidence peaked); and cumulative incidence rates between school-based indicators and sero-epidemiological pdmH1N1 incidence (estimated from changes in prevalence of A/California/7/2009 H1N1 hemagglutination inhibition titers ≥ 40 between pre-epidemic and post-epidemic sera). Variation in Sch-FRI rates in the 6 schools was also investigated through a Bayesian hierarchical model., Results: By week 30, for primary and secondary school children respectively, 63% and 79% of incidence for Sch-LCC had occurred, compared with 50% and 52% for GP-ILI data, and 48% and 53% for Sch-FRI. There were 1,187 notified cases and 7,588 episodes in the Sch-LCC and Sch-DTM systems; given school enrollment of 485,723 children, this represented 0.24 cases and 1.6 episodes per 100 children respectively. Mean Sch-FRI rate was 28.8 per 100 children (95% CI: 27.7 to 29.9) in the 6 schools. We estimate from serology that 41.8% (95% CI: 30.2% to 55.9%) of primary and 43.2% (95% CI: 28.2% to 60.8%) of secondary school-aged children were infected. Sch-FRI rates were similar across the 6 schools (23 to 34 episodes per 100 children), but there was widespread variation by classrooms; in the hierarchical model, omitting age and school effects was inconsequential but neglecting classroom level effects led to highly significant reductions in goodness of fit., Conclusions: Epidemic curves from Sch-FRI were comparable to GP-ILI data, and Sch-FRI detected substantially more infections than Sch-LCC and Sch-DTM. Variability in classroom attack rates suggests localized class-room transmission.
- Published
- 2012
- Full Text
- View/download PDF
17. Seroconversion and asymptomatic infections during oseltamivir prophylaxis against Influenza A H1N1 2009.
- Author
-
Lee VJ, Yap J, Tay JK, Barr I, Gao Q, Ho HJ, Tan BH, Kelly PM, Tambyah PA, Kelso A, and Chen MI
- Subjects
- Adult, Cohort Studies, Disease Outbreaks, Hemagglutination Inhibition Tests, Humans, Male, Military Personnel, Nasopharynx virology, RNA, Viral isolation & purification, Reverse Transcriptase Polymerase Chain Reaction, Singapore epidemiology, Surveys and Questionnaires, Young Adult, Antibodies, Viral blood, Antiviral Agents administration & dosage, Chemoprevention methods, Influenza A Virus, H1N1 Subtype immunology, Influenza, Human diagnosis, Influenza, Human prevention & control, Oseltamivir administration & dosage
- Abstract
Background: Anti-viral prophylaxis is used to prevent the transmission of influenza. We studied serological confirmation of 2009 Influenza A (H1N1) infections during oseltamivir prophylaxis and after cessation of prophylaxis., Methods: Between 22 Jun and 16 Jul 09, we performed a cohort study in 3 outbreaks in the Singapore military where post-exposure oseltamivir ring chemoprophylaxis (75 mg daily for 10 days) was administered. The entire cohort was screened by RT-PCR (with HA gene primers) using nasopharyngeal swabs three times a week. Three blood samples were taken for haemagglutination inhibition testing--at the start of outbreak, 2 weeks after completion of 10 day oseltamivir prophylaxis, and 3 weeks after the pandemic's peak in Singapore. Questionnaires were also administered to collect clinical symptoms., Results: 237 personnel were included for analysis. The overall infection rate of 2009 Influenza A (H1N1) during the three outbreaks was 11.4% (27/237). This included 11 index cases and 16 personnel (7.1%) who developed four-fold or higher rise in antibody titres during oseltamivir prophylaxis. Of these 16 personnel, 8 (3.5%) were symptomatic while the remaining 8 personnel (3.5%) were asymptomatic and tested negative on PCR. Post-cessation of prophylaxis, an additional 23 (12.1%) seroconverted. There was no significant difference in mean fold-rise in GMT between those who seroconverted during and post-prophylaxis (11.3 vs 11.7, p = 0.888). No allergic, neuropsychiatric or other severe side-effects were noted., Conclusions: Post-exposure oseltamivir prophylaxis reduced the rate of infection during outbreaks, and did not substantially increase subsequent infection rates upon cessation. Asymptomatic infections occur during prophylaxis, which may confer protection against future infection. Post-exposure prophylaxis is effective as a measure in mitigating pandemic influenza outbreaks.
- Published
- 2010
- Full Text
- View/download PDF
18. Reproductive health for refugees by refugees in Guinea II: sexually transmitted infections.
- Author
-
Chen MI, von Roenne A, Souare Y, von Roenne F, Ekirapa A, Howard N, and Borchert M
- Abstract
Background: Providing reproductive and sexual health services is an important and challenging aspect of caring for displaced populations, and preventive and curative sexual health services may play a role in reducing HIV transmission in complex emergencies. From 1995, the non-governmental "Reproductive Health Group" (RHG) worked amongst refugees displaced by conflicts in Sierra Leone and Liberia (1989-2004). RHG recruited refugee nurses and midwives to provide reproductive and sexual health services for refugees in the Forest Region of Guinea, and trained refugee women as lay health workers. A cross-sectional survey was conducted in 1999 to assess sexual health needs, knowledge and practices among refugees, and the potential impact of RHG's work., Methods: Trained interviewers administered a questionnaire on self-reported STI symptoms, and sexual health knowledge, attitudes and practices to 445 men and 444 women selected through multistage stratified cluster sampling. Chi-squared tests were used where appropriate. Multivariable logistic regression with robust standard errors (to adjust for the cluster sampling design) was used to assess if factors such as source of information about sexually transmitted infections (STIs) was associated with better knowledge., Results: 30% of women and 24% of men reported at least one episode of genital discharge and/or genital ulceration within the past 12 months. Only 25% correctly named all key symptoms of STIs in both sexes. Inappropriate beliefs (e.g. that swallowing tablets before sex, avoiding public toilets, and/or washing their genitals after sex protected against STIs) were prevalent. Respondents citing RHG facilitators as their information source were more likely to respond correctly about STIs; RHG facilitators were more frequently cited than non-healthcare information sources in men who correctly named the key STI symptoms (odds ratio (OR) = 5.2, 95% confidence interval (CI) 1.9-13.9), and in men and women who correctly identified effective STI protection methods (OR = 2.9, 95% CI 1.5-5.8 and OR = 4.6, 95% CI 1.6-13.2 respectively)., Conclusion: Our study revealed a high prevalence of STI symptoms, and gaps in sexual health knowledge in this displaced population. Learning about STIs from RHG health facilitators was associated with better knowledge. RHG's model could be considered in other complex emergency settings.
- Published
- 2008
- Full Text
- View/download PDF
19. Reproductive health services for refugees by refugees in Guinea I: family planning.
- Author
-
Howard N, Kollie S, Souare Y, von Roenne A, Blankhart D, Newey C, Chen MI, and Borchert M
- Abstract
Background: Comprehensive studies of family planning (FP) in refugee camps are relatively uncommon. This paper examines gender and age differences in family planning knowledge, attitudes, and practices among Sierra Leonean and Liberian refugees living in Guinea., Methods: In 1999, a cross-sectional survey was conducted of 889 reproductive-age men and women refugees from 48 camps served by the refugee-organised Reproductive Health Group (RHG). Sampling was multi-stage with data collected for socio-demographics, family planning, sexual health, and antenatal care. Statistics were calculated for selected indicators., Results: Women knew more about FP, although men's education reduced this difference. RHG facilitators were the primary source of reproductive health information for all respondents. However, more men then women obtained information from non-health sources, such as friends and media. Approval of FP was high, significantly higher in women than in men (90% vs. 70%). However, more than 40% reported not having discussed FP with their partner. Perceived service quality was an important determinant in choosing where to get contraceptives. Contraceptive use in the camps served by RHG was much higher than typical for either refugees' country of origin or the host country (17% vs. 3.9 and 4.1% respectively), but the risk of unwanted pregnancy remained considerable (69%)., Conclusion: This refugee self-help model appeared largely effective and could be considered for reproductive health needs in similar settings. Having any formal education appeared a major determinant of FP knowledge for men, while this was less noticeable for women. Thus, FP communication strategies for refugees should consider gender-specific messages and channels.
- Published
- 2008
- Full Text
- View/download PDF
20. Early prediction of median survival among a large AIDS surveillance cohort.
- Author
-
Enanoria WT, Hubbard AE, van der Laan MJ, Chen M, Ruiz J, and Colford JM Jr
- Subjects
- Acquired Immunodeficiency Syndrome diagnosis, California epidemiology, Cohort Studies, Forecasting methods, Humans, Kaplan-Meier Estimate, Probability, Public Health Informatics, Registries, Risk Assessment, Risk Factors, Time Factors, Acquired Immunodeficiency Syndrome mortality, Population Surveillance methods, Survival Analysis
- Abstract
Background: For individuals with AIDS, data exist relatively soon after diagnosis to allow estimation of "early" survival quantiles (e.g., the 0.10, 0.15, 0.20 and 0.30 quantiles, etc.). Many years of additional observation must elapse before median survival, a summary measure of survival, can be estimated accurately. In this study, a new approach to predict AIDS median survival is presented and its accuracy tested using AIDS surveillance data., Methods: The data consisted of 96,373 individuals who were reported to the HIV/AIDS Reporting System of the California Department of Health Services Office of AIDS as of December 31, 1996. We defined cohorts based on quarter year of diagnosis (e.g., the "931" cohort consists of individuals diagnosed with AIDS in the first quarter of 1993). We used early quantiles (estimated using the Inverse Probability of Censoring Weighted estimator) of the survival distribution to estimate median survival by assuming a linear relationship between the earlier quantiles and median survival. From this model, median survival was predicted for cohorts for which a median could not be estimated empirically from the available data. This prediction was compared with the actual medians observed when using updated survival data reported at least five years later., Results: Using the 0.15 quantile as the predictor and the data available as of December 31, 1996, we were able to predict the median survival of four cohorts (933, 934, 941, and 942) to be 34, 34, 31, and 29 months. Without this approach, there were insufficient data with which to make any estimate of median survival. The actual median survival of these four cohorts (using data as of December 31, 2001) was found to be 32, 40, 46, and 80 months, suggesting that the accuracy for this approach requires a minimum of three years to elapse from diagnosis to the time an accurate prediction can be made., Conclusion: The results of this study suggest that early and accurate prediction of median survival time after AIDS diagnosis may be possible using early quantiles of the survival distribution. The methodology did not seem to work well during a period of significant change in survival as observed with highly active antiretroviral treatment, but results suggest that it may work well in a time of more gradual improvement in survival.
- Published
- 2007
- Full Text
- View/download PDF
21. Clinical and epidemiological predictors of transmission in Severe Acute Respiratory Syndrome (SARS).
- Author
-
Chen MI, Chow AL, Earnest A, Leong HN, and Leo YS
- Subjects
- Adult, Case-Control Studies, Female, Humans, L-Lactate Dehydrogenase blood, Logistic Models, Male, Middle Aged, Patient Isolation, Risk Factors, Severe Acute Respiratory Syndrome diagnosis, Singapore epidemiology, Severe Acute Respiratory Syndrome epidemiology, Severe Acute Respiratory Syndrome transmission
- Abstract
Background: Only a minority of probable SARS cases caused transmission. We assess if any epidemiological or clinical factors in SARS index patients were associated with increased probability of transmission., Methods: We used epidemiological and clinical data on probable SARS patients admitted to Tan Tock Seng Hospital. Using a case-control approach, index patients who had probable SARS who subsequently transmitted the disease to at least one other patient were analysed as "cases" against patients with no transmission as "controls", using multivariate logistic regression analysis., Results: 98 index patients were available for analysis (22 with transmission, 76 with no transmission). Covariates positively associated with transmission in univariate analysis at p < 0.05 included delay to isolation (Day 7 of illness or later), admission to a non-isolation facility, pre-existing chronic respiratory disease and immunosuppressive disease, need for oxygen, shortness of breath, vomiting, and higher lactate dehydrogenase levels and higher neutrophil counts. In the multivariate analysis, only three factors were significant: delay to isolation, admission to a non-isolation facility and higher lactate dehydrogenase levels of >650 IU/L (OR 6.4, 23.8 and 4.7 respectively)., Conclusion: Clinical and epidemiological factors can help us to explain why transmission was observed in some instances but not in others.
- Published
- 2006
- Full Text
- View/download PDF
22. Exploring if day and time of admission is associated with average length of stay among inpatients from a tertiary hospital in Singapore: an analytic study based on routine admission data.
- Author
-
Earnest A, Chen MI, and Seow E
- Subjects
- Adult, After-Hours Care, Aged, Chronology as Topic, Cohort Studies, Female, Holidays, Hospital Information Systems, Hospitals, Urban organization & administration, Humans, Male, Middle Aged, Multivariate Analysis, Singapore, Time Factors, Admitting Department, Hospital organization & administration, Episode of Care, Hospitals, Urban statistics & numerical data, Length of Stay statistics & numerical data, Patient Admission
- Abstract
Background: It has been postulated that patients admitted on weekends or after office hours may experience delays in clinical management and consequently have longer length of stay (LOS). We investigated if day and time of admission is associated with LOS in Tan Tock Seng Hospital (TTSH), a 1,400 bed acute care tertiary hospital serving the central and northern regions of Singapore., Methods: This was a historical cohort study based on all admissions from TTSH from 1st September 2003 to 31st August 2004. Data was extracted from routinely available computerized hospital information systems for analysis by episode of care. LOS for each episode of care was log-transformed before analysis, and a multivariate linear regression model was used to study if sex, age group, type of admission, admission source, day of week admitted, admission on a public holiday or eve of public holiday, admission on a weekend and admission time were associated with an increased LOS., Results: In the multivariate analysis, sex, age group, type of admission, source of admission, admission on the eve of public holiday and weekends and time of day admitted were independently and significantly associated with LOS. Patients admitted on Friday, Saturday or Sunday stayed on average 0.3 days longer than those admitted on weekdays, after adjusting for potential confounders; those admitted on the eve of public holidays, and those admitted in the afternoons and after office hours also had a longer LOS (differences of 0.71, 1.14 and 0.65 days respectively)., Conclusion: Cases admitted over a weekend, eve of holiday, in the afternoons, and after office hours, do have an increased LOS. Further research is needed to identify processes contributing to the above phenomenon.
- Published
- 2006
- Full Text
- View/download PDF
23. Predictors of failed attendances in a multi-specialty outpatient centre using electronic databases.
- Author
-
Lee VJ, Earnest A, Chen MI, and Krishnan B
- Subjects
- Adult, Aged, Databases as Topic, Female, Forecasting, Health Services Accessibility statistics & numerical data, Humans, Logistic Models, Male, Middle Aged, Odds Ratio, Probability, Singapore, Treatment Refusal ethnology, Appointments and Schedules, Outpatient Clinics, Hospital statistics & numerical data, Patient Dropouts statistics & numerical data, Treatment Refusal statistics & numerical data
- Abstract
Background: Failure to keep outpatient medical appointments results in inefficiencies and costs. The objective of this study is to show the factors in an existing electronic database that affect failed appointments and to develop a predictive probability model to increase the effectiveness of interventions., Methods: A retrospective study was conducted on outpatient clinic attendances at Tan Tock Seng Hospital, Singapore from 2000 to 2004. 22864 patients were randomly sampled for analysis. The outcome measure was failed outpatient appointments according to each patient's latest appointment., Results: Failures comprised of 21% of all appointments and 39% when using the patients' latest appointment. Using odds ratios from the mutliple logistic regression analysis, age group (0.75 to 0.84 for groups above 40 years compared to below 20 years), race (1.48 for Malays, 1.61 for Indians compared to Chinese), days from scheduling to appointment (2.38 for more than 21 days compared to less than 7 days), previous failed appointments (1.79 for more than 60% failures and 4.38 for no previous appointments, compared with less than 20% failures), provision of cell phone number (0.10 for providing numbers compared to otherwise) and distance from hospital (1.14 for more than 14 km compared to less than 6 km) were significantly associated with failed appointments. The predicted probability model's diagnostic accuracy to predict failures is more than 80%., Conclusion: A few key variables have shown to adequately account for and predict failed appointments using existing electronic databases. These can be used to develop integrative technological solutions in the outpatient clinic.
- Published
- 2005
- Full Text
- View/download PDF
24. Using autoregressive integrated moving average (ARIMA) models to predict and monitor the number of beds occupied during a SARS outbreak in a tertiary hospital in Singapore.
- Author
-
Earnest A, Chen MI, Ng D, and Sin LY
- Subjects
- Female, Forecasting, Humans, Infant, Infant, Newborn, Male, Middle Aged, Retrospective Studies, Singapore epidemiology, Bed Occupancy statistics & numerical data, Disease Outbreaks, Hospitals, Urban statistics & numerical data, Patient Admission statistics & numerical data, Patient Isolation statistics & numerical data, Proportional Hazards Models, Severe Acute Respiratory Syndrome epidemiology
- Abstract
Background: The main objective of this study is to apply autoregressive integrated moving average (ARIMA) models to make real-time predictions on the number of beds occupied in Tan Tock Seng Hospital, during the recent SARS outbreak., Methods: This is a retrospective study design. Hospital admission and occupancy data for isolation beds was collected from Tan Tock Seng hospital for the period 14th March 2003 to 31st May 2003. The main outcome measure was daily number of isolation beds occupied by SARS patients. Among the covariates considered were daily number of people screened, daily number of people admitted (including observation, suspect and probable cases) and days from the most recent significant event discovery. We utilized the following strategy for the analysis. Firstly, we split the outbreak data into two. Data from 14th March to 21st April 2003 was used for model development. We used structural ARIMA models in an attempt to model the number of beds occupied. Estimation is via the maximum likelihood method using the Kalman filter. For the ARIMA model parameters, we considered the simplest parsimonious lowest order model., Results: We found that the ARIMA (1,0,3) model was able to describe and predict the number of beds occupied during the SARS outbreak well. The mean absolute percentage error (MAPE) for the training set and validation set were 5.7% and 8.6% respectively, which we found was reasonable for use in the hospital setting. Furthermore, the model also provided three-day forecasts of the number of beds required. Total number of admissions and probable cases admitted on the previous day were also found to be independent prognostic factors of bed occupancy., Conclusion: ARIMA models provide useful tools for administrators and clinicians in planning for real-time bed capacity during an outbreak of an infectious disease such as SARS. The model could well be used in planning for bed-capacity during outbreaks of other infectious diseases as well.
- Published
- 2005
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.