published_or_final_version / Nursing Studies / Master / Master of Nursing

published_or_final_version / Medicine / Master / Doctor of Medicine

published_or_final_version / Public Health / Master / Master of Public Health

The existence, probability and control measures of airborne infections have been widely discussed for centuries. Although public belief regarding airborne infection kept on altering throughout the entire history of medicine and is still controversial, many airborne transmission experiments and airborne infection outbreak analyses have been carried out. Different airborne transmission models have been built and various airborne control measures have been evaluated. One of the major knowledge gaps obstructing applications of some airborne control measures in clinical practices and public applications is that there is a lack of evidence in proving the effectiveness of such measures. Ventilation as an important airborne infection control method can be achieved by opening windows, or increasing the outdoor air supply rate in mechanical ventilation systems or indirectly by using filters and ultraviolet equipments. However the applications of ventilation in infection control were largely restricted to isolation rooms rather than regarded as a public control measure. In this study we focus on evaluating the effectiveness of ventilation as a community measure. Results, therefore, can provide evidence for using ventilation as a public health measure for controlling respiratory diseases transmitted by the airborne route or multi-routes. Two mathematical modeling approaches (deterministic model and social network model) are adopted to estimate different airborne diseases outbreaks with a focus on ventilation and a corresponding analysis of their relative effectiveness compared with other public health measures. A comprehensive understanding of detailed control strategies (including both engineering and public health control) will be achieved through gradually complicated and realistic models. It’s commonly believed that many respiratory infections are transmitted through multiple routes including airborne, droplet-borne and contact routes. Hence the effectiveness of airborne control measures was doubted when the airborne route was not dominant. Therefore, we developed a model to simulate partially airborne transmitted diseases outbreaks and evaluated the relative effectiveness of ventilation when the role of airborne transmission altered. Knowing the complex transmission mechanisms of respiratory transmission and the role of the airborne route in the transmission process is essential in determining the effectiveness of airborne control measures. Hence in this study we also tested the virus exposures dose to infectious patients at different distances when patients were carrying out different respiratory activities. A complex model considering transmission mechanisms of respiratory infections was also built to evaluate the influence of the transmission route in large scale outbreak simulations. The results showed that increasing ventilation rate especially in homes, offices and classrooms is an effective control method for controlling airborne and partially airborne transmitted infections. Combining isolation and increasing ventilation rate can reach similar or even better control effect compared with other general public health interventions such as vaccination. This finding suggested the important role of ventilation in airborne infectious disease prevention and intervention. The ventilation rate required by existing ventilation standards such as ASHRAE 62 might be too low for the purpose of controlling possible airborne outbreaks. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Background: Blood safety is important to blood transfusion. As men who have sex with men (MSM) are considered to have a higher risk of sexually transmitted infections (STIs) compared to the general population, blood donations from MSM may lead to a higher risk of transfusion-transmitted infections (TTIs). For this reason, many countries have established lifelong deferral policies for MSM blood donors since 1980s. Research have been conducted to evaluate the risks and benefits of relaxing MSM deferral policies from lifelong to a finite period, and countries such as the United Kingdom have implemented such relaxation in recent years. Nevertheless, there remains a lack of risk-benefit analyses on this topic in many countries, especially the developing ones. This review can help such countries to reconsider their MSM deferral policies. Objective: The objectives of this review are (i) to review the current deferral policies of blood donation from MSM implemented in major countries and (ii) to review the major determining factors in the risk-benefit analyses of these countries. Method: PubMed, Google Scholar, and China Journal Net were used for literature search. Only literatures with abstract and/or available full text in English or Chinese were included. The PICOS approach was used for study selection, and 37 articles were finally selected. Surveys, cohort studies, cross-sectional studies reviews, and national reports were included in this systematic review. Result: Countries with permanent/indefinite MSM deferral policy include the United States, Canada, France, Mexico, Germany, Norway, Sweden and China (including Hong Kong). Countries with a finite deferral period include New Zealand (5 years), the United Kingdom (12 months), Australia (12 months), Brazil (12 months), Argentina (12 months), Japan (6 months) and South Africa (6 months). Countries without specific deferral criteria for MSM include Spain, Italy, Poland and Russia. The recent relaxation of deferral policies was based on scientific evidence provided by risk-benefit analyses that evaluated the residual risk of TTIs associated with alternative deferral policies. Major determining factors of risk-benefit analyses include the following: 1. epidemiological characteristics that determine the proportion of MSM among HIV-infected patients; 2. screening technologies that have shortened the window period and improved the early detection of STIs; and 3. non-compliance after relaxation, which determines the increasing risk of TTIs. Conclusion: Majority of countries that have recently relaxed their deferral policies for MSM blood donor reduced the deferral period to 12 or 6 months. Most of the risk-benefit analyses found that relaxation of deferral policies for MSM blood donors would lead to a relatively small increase in the risk of TTIs. Policies aimed at lowering the non-compliance may be an effective way to reduce the residual risk of TTIs from MSM blood donors who are within the window period. / published_or_final_version / Public Health / Master / Master of Public Health

Influenza epidemics have always been a constant public health threat to human populations. Recent societal developments and demographics changes have put us at increased risk of a widespread and potentially deadly influenza epidemic. Antiviral prophylaxis may provide an important epidemic intervention measure especially against influenza epidemic caused by novel influenza viruses where there will be no effective epidemic-specific vaccines available at the initial phase of the epidemic. Antiviral prophylaxis is listed as a fundamental component of the Hong Kong Preparedness Plan for Influenza Pandemics, however the rationale of such plan is not supported by public presentation of scientific evidence and no details of the actual antiviral prophylaxis plan are provided. With a majority of its stockpile set to expire in the very near future, we would like to know if antiviral prophylaxis is an effective intervention strategy against influenza epidemic and should antiviral stockpiling be continued. We identified relevant studies and reviewed the effectiveness of antiviral prophylaxis in preventing influenza infections at the individual, household and population level. We found that prophylactic treatment with Oseltamivir or Zanamivir are both effective in preventing influenza infections at the individual and household level. Both antivirals are well tolerated and neither is associated with major adverse events. Antiviral prophylaxis is effective in mitigating the public health impact of an influenza epidemic such as number of clinical influenza infections, hospitalization and deaths. However, antiviral prophylaxis alone may not be sufficient to contain or avert an influenza epidemic or delay the epidemic progress long enough for public health resources such as epidemic-specific vaccines to be acquired. In addition, the emergence of antiviral resistance and various logistics constraints will hamper the effectiveness of antiviral prophylaxis in containing influenza epidemics. We suggest the use of antiviral prophylaxis as the key intervention to mitigate influenza epidemics, however, with special considerations taken into hedging antiviral resistance and fulfilling the logistics requirements in order to make antiviral prophylaxis effective. In addition, we recommend public health authorities to take a multi-factorial approach in tackling highly transmissible influenza epidemics by incorporating other non-pharmaceutical interventions such as quarantine, school closures and boarder restrictions into the their antiviral prophylaxis-based containment plan. / published_or_final_version / Public Health / Master / Master of Public Health

Throughout history influenzas have consistently qualified as one of the top killers amongst common infectious diseases and it continues today to afflict millions in spite of our vast efforts to curb its effects. The World Health Organization (WHO) notes annual deaths of between 250,000 to 500,000 due to influenza. Alternative medicines have been traditionally used to treat this illness in the past, and have begun to experience an increase in popularity these days as a complementary supplement to improve treatment of influenza’s symptoms. The use of such natural extracts as Echinacea, ascorbic acid, and “Kan Jang” aim to mitigate symptoms and increase the efficiency of the healing process. Their use, however, has been scrutinized and somewhat controversial when looking at their effectiveness. Having such wide-spread use of these treatments, it is important to understand just how beneficial these alternative routes are when treating infectious diseases like influenza. The objective of this literature review is to assess the use of these traditional medicines in the treatment of influenza and influenza-like-illnesses (ILI). In order to do this, randomized controlled trials were studied to establish any benefits these medicines might provide in the treatment of symptoms and the prevention of influenza. Treatment groups with the three different alternative medicines were respectively compared to control groups without any treatment through singular symptoms and duration of these symptoms, as well as prevention of multiple infections. / published_or_final_version / Public Health / Master / Master of Public Health

Infection control is an often neglected clinical subject in Hong Kong until the outbreak of severe acute respiratory syndrome (SARS) in 2003. A total of eight healthcare workers, including four medical doctors, succumbed as a result of nosocomial acquisition of SARS-coronavirus (SARS-CoV) at the time. Since then, the importance of infection control practice was much better appreciated by the frontline healthcare workers, as it can be a matter of life-or-death. My thesis summarized our research on the proactive infection control measures to prevent nosocomial transmission of respiratory and gastrointestinal viruses, to control emerging and endemic antibiotic-resistant bacteria, and on the management of unprecedented infection outbreaks in the hospital. Promotion of hand hygiene is the cornerstone of proactive infection control measures. By adopting the concept and practice of directly-observed hand hygiene, we demonstrated successful control of outbreaks and prevention for both respiratory and gastroenteritis viruses. Introduction of electronic devices for continuous monitoring of hand hygiene compliance in high risk clinical areas provides an opportunity for immediate feedback and timely education to frontline staffs. The global dissemination of multiple drug resistant organisms (MDROs) such as methicillin-resistant Staphylococcus aureus (MRSA), community-associated MRSA (CA-MRSA), vancomycin-resistant enterococcus (VRE), hypervirulent clone of Clostridium difficile, extended-spectrum beta-lactamase (ESBL) producing organisms, and the recently described carbapenem-resistant enterobacteriaceae (CRE), pose a great challenge to the infection control professionals. In Hong Kong, MRSA has been endemic for more than two decades. Although we proved that the appropriate use of single room isolation and hand hygiene can significantly reduce the incidence of nosocomial MRSA in the adult intensive care unit, the isolation facilities remain limited in the general medical and surgical units. Innovations are much in need to manage this old and persistent problem. Therefore, we demonstrated that use of antibiotics, in particular beta-lactams and fluoroquinolones, could increase the risk of environmental contamination by increasing microbial density of MRSA in the anterior nares by 2-3 log10 in as little as 1 week. We also found that some MRSA strains such as spa types t1081 and t037 were more transmissible. Based on these findings, we prioritized our isolation facilities for those patients who are heavily colonized or infected with highly transmissible spa-type t1081, especially when they are receiving antibiotic therapy. Along with our enhancement of hand hygiene practices and antibiotic stewardship program, the incidence of MRSA bacteremia per 1000-patient-days was the lowest among the seven hospital clusters in Hong Kong. We believe that our experience in the control of the MRSA can be extended to contain the spread of CA-MRSA and other MDROs. Besides the prevailing infectious diseases with high endemicity, we have to be vigilant against other potential outbreaks due to uncommon micro-organisms such as the polymicrobial outbreak in patients undergoing intermittent peritoneal dialysis caused by hospital renovation, the unprecedented outbreak of intestinal mucormycosis caused by Rhizopus microsporous among the patients with hematological malignancy, and the nosocomial outbreak of legionellosis in our locality. Extensive outbreak investigations were performed, which demonstrated that environmental factors were also important in causing nosocomial outbreaks. / published_or_final_version / Microbiology / Master / Doctor of Medicine

Child maltreatment—a serious public health problem—is a global phenomenon. Parenting programs are considered effective approaches to preventing child maltreatment; however, comprehensive understanding is still lacking of the effectiveness of such programs in all areas of outcomes and the way parenting programs work. This thesis consists of two parts: a quantitative synthesis of high-level evidence about program effects and a qualitative integration of program process. The thesis employs two research methods: meta-analytic review and systematic review. I searched 11 electronic databases to identify studies published between 2000 and 2012. Forty-two studies meeting the eligibility criteria were included in the systematic review, and 21 of these were included in the meta-analysis. The total random effect size was 0.338. The research found that parenting programs successfully reduced substantiated child maltreatment reports. The programs also reduced risk factors and enhanced protective factors associated with child maltreatment. However, program effects began to decrease in the first year after program completion. Parenting programs function by remediating parental cognition, thus changing parenting behaviors and enhancing parent-child relationships. The successful program components include teaching child-rearing knowledge, improving parenting skills and changing parents’ inappropriate attitudes towards children. Parenting programs are demonstrated to be effective public health approaches to avoiding child maltreatment. Parenting programs could produce positive effects in both low- and middle-income countries, as well as high-income countries. The study recommends a longer-term intervention beginning prenatally or at an early age of the children and involving more male caregivers. The evidence-based service of parenting programs could be widely adopted in future practices. The research also indicates that parenting programs could be applicable within the Chinese context, where such programs have not been widely used to date. / published_or_final_version / Social Work and Social Administration / Master / Master of Philosophy

Background: End Stage Renal Disease (ESRD) is one of the commonest diseases in Hong Kong. Patient with ESRD needs to start dialysis for life maintenance. Peritoneal dialysis (PD) is the predominant dialysis modality for home dialysis patients. More than 80% of dialysis patients in Hong Kong receive PD. However, it also brings out some PD-related infectious complication such as tenckhoff exit-site infection, tenckhoff tunnel infection and PD peritonitis. These complications markedly contribute to treatment failure in PD patients. Especially PD peritonitis, it remains a leading complication of PD. Also it is a main cause of patients switch to haemodialysis (HD)and discontinue PD. Nevertheless, if the primary prevention of PD education do better, research evidences have shown that peritonitis infection rate of PD patients can be effectively reduced. It can be achieve by the utilization of effective education strategies and advanced training skills to enhance patients’ knowledge and skills of peritoneal dialysis. Purpose: This written proposal aims to identify the best evidence of PD education and to develop a guideline for this health education programme. The goal of the programme is to reduce the rate of PD-related infection for patients who started PD treatment at home after first CAPD training and education. Method: A total of 12 studies which focused on PD education and strategies for reducing PD-related infections were searched from electronic databases. Data extraction and critical appraisal were performed on these 12 studies. After the integrative review, the implementation potential was assessed. The results shown that the transferability of finding is high and it is feasible to conduct the proposed innovation. Then, the evidence-based guideline for PD education programme were developed and based on the high and medium level of evidence with grades of recommendation stated. Before implementing the proposed innovation, a communication plan was developed and targeted the various stakeholders (the administrators, nurses, patients and their relatives). The proposer would initiate the change and the programme leading group would guide and sustain the proposed innovation. The next process was planning a pilot study to examine the feasibility of the proposed innovation before implementation. Finally, different outcomes of the programme has been identified and evaluated in the evaluation plan. The methods for data analysis were formulated. Conclusion: The proposed peritoneal dialysis education programme with best evidences support is worthy to be adopted in the clinical setting for the beneficial of PD patients to reduce their PD-related infectious complications. / published_or_final_version / Nursing Studies / Master / Master of Nursing