Objectives: By summarizing and comparing the pattern of invasive pneumococcal disease (IPD) in the 4 areas (namely Hong Kong, other parts of China, United States and Thailand) at different stages of implementation of universal pneumococcal vaccination, a snapshot picture could be obtained to visualize how pneumococcal vaccination has impacted upon various important measures, including the burden of IPD, prevalent serotypes, antimicrobial resistance, risk factors of IPD, to guide us on the next step to optimize our ability to combat against IPD. Methods: To achieve the objective, a systematic search through PubMed, Medline, Cochrane Library, EmBase, CINAHL, and the China Journal Net (for Chinese journal articles to obtain a more comprehensive data for “other parts of mainland) has been performed. Articles were selected according to the inclusion and exclusion criteria, and in straight accordance to the literature search and article retrieval steps as described in the methodology. The quality of the articles was assessed by the STROBE (Strengthening the Reporting of Observational studies in Epidemiology) checklists. Results: In general, there was decline in IPD incidence after PCV vaccination, but the problem of serotype replacement and antimicrobial resistance was still an ongoing problem, which differs geographically. Conclusion: From the above data, we could see the significant impact on PCV on reduction of incidence in IPD as shown in United States, however, it was also very clear that unless development of non-serotype specific vaccine become available to us, we are still facing the problem of serotype replacement and that we need to have regular surveillance, as in the case of United States, to supply the data for timely replacement of new PCV combating the emerging serotypes, such that we would still be in the safe ground. In Hong Kong, the statutory reporting of IPD to Centre for Health and Protection (CHP) has been effective since 2/1/201443, after the start of universal immunization since October 2008, followed by PCV10 in 2009 and PCV13 in December 2011, we seems lacking behind on the surveillance. With the surveillance started by CHP, we hope to understand the Hong Kong situation better and with more published data for our local burden and serotype pattern of IPD. It is interesting to note that the antimicrobial pattern does vary geographically, even in US with universal immunization. This suggests that while PCV was helping us to reduce the penicillin resistant strain, another more important factor – the practice of use of antibiotics- is still operating to effect on the overall antibiotic resistance. The pattern that rural Thailand was having much much less penicillin resistance as compared to urban Bangkok, where antibiotic is more readily available, also supports this explanation. / published_or_final_version / Public Health / Master / Master of Public Health

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Epidemiology in the field of Epidemiology & Biostatistics January 2014 / Studies have shown an increased risk of mortality amongst adults with invasive pneumococcal disease (IPD) with certain serotypes but there are no data from South Africa. We aimed to determine the association between serotypes and in-hospital mortality among adults aged 15 years and older with IPD in South Africa. Methods IPD cases were identified through the GERMS-SA national laboratory-based surveillance programme. Patient data from 25 enhanced surveillance sites from 2003-2008 (pre-pneumococcal conjugate vaccine introduction) with available data on serotype and in-hospital outcome were used. We assessed the association between the 20 most common serotypes and mortality among patients ≥15 years of age using univariate and multivariable logistic regression models. Results From January 2003 through December 2008, there were 3953 cases of IPD amongst adults older than 15 years of age meeting the study inclusion criteria. Amongst the 20 commonest serotypes, the incidence of serotypes 4, 19A, 23F and 18C increased significantly, and serotypes 1, 25 and 5 decreased significantly from 2003 to 2008. Serotype 1 was the commonest serotype overall (16%, 651/3953), followed by serotype 19A (11%, 443/3953) and serotype 4 (7%, 289/3953). The case-fatality ratio (CFR) was 55% (641/1166) for meningitis and 23% (576/2484) for bacteremia (p<0.001). Serotype 19F had the highest CFR of 48% (100/207), followed by 39% (99/252) for serotype 23F and 38% (246/651) for serotype 1. On multivariable analysis, factors independently associated with mortality were disease caused by serotypes 1 (OR 1.93, 95% CI 1.05–3.53) and 19F (OR 2.89, 95% CI 1.38–6.06) compared to serotype 4; increasing age (25-44 years, OR 1.75, 95% CI 1.03–2.95; 45-64 years, OR 3.56, 95% CI 2.00–6.35; ≥65 years, OR 5.17, 95% CI 1.89–14.14; compared to 15-24 years); living in provinces with intermediate (OR 1.65, 95% CI 1.16–2.35) or high poverty rates (OR 1.72, 95% CI 1.02–2.92) compared to provinces with low poverty rates; having meningitis (OR 4.07, 95% CI 2.98–5.55) compared to bacteremia; prior antibiotic treatment in the last two months (OR 3.93, 95% CI 2.50–6.20); inappropriate antibiotic treatment (OR 2.37, 95% CI 1.74–3.22) and positive HIV status (OR 1.69, 95% CI 1.04–2.75). Conclusion Serotypes associated with increased mortality are included in the 10-and-13-valent pneumococcal conjugate vaccine and may be expected to become less common in adults as a result of indirect effects following routine immunization in infants. HIV-infected adults experience increased mortality and the more widespread availability of antiretroviral therapy is likely to substantially improve the quality of life of HIV-infected individuals in terms of physical and mental health and decrease the incidence of IPD and therefore mortality.

published_or_final_version / Public Health / Master / Master of Public Health

Background Pneumococcal disease, caused by Streptococcus pneumoniae (S. pneumoniae), leads to a great burden of morbidity and mortality globally, especially in developing countries. World Health Organization (WHO) estimated that 476,000 out of 8.8 million global annual deaths in children under 5 years old in 2008 were due to pneumococcal infection. Currently there are 2 second generation pneumococcal conjugate vaccines (PCVs) targeted at children, the 10-valent pneumococcal conjugate vaccine (PCV-10) and 13-valent pneumococcal conjugate vaccine (PCV-13) available in the market for the prevention of pneumococcal disease. Nowadays, about half of the countries already included PCVs into their National Immunization Programme (NIP) and around one-fourth are planning the introduction. The objective of this systematic review is to evaluate the cost-effectiveness of PCV-10 and PCV-13 so that the results could inform policy decisions of including PCVs into the NIP. Methods A systematic review was conducted by searching from 2 databases (PubMed and Medline) for the economic evaluation studies of the PCV-10 and PCV-13. Information of the design and characteristics of studies, burden of pneumococcal disease assumption, and baseline vaccine efficacy assumptions were extracted and results were presented in incremental cost-effectiveness ratio (ICER). Results Eleven studies were included, with 4 studies done in Europe, 3 in South America, 2 in Africa, 1 in Asia and 1 across North America and Europe. The results varied greatly among studies, with 5 of them reporting PCV-10 to be more cost-effective and/or cost-saving, while 4 of them reporting PCV-13 to be more cost-effective and/or cost-saving, and 2 of them concluded in a different way: PCV-10 was more cost-effective and cost-saving, however PCV-13 would lead to higher life-years gained (LYG) and/or disability-adjusted life years (DALYs) averted. Conclusion Due to the uncertainties in the clinical and epidemiological parameters, the unavailability of the data of local disease burden, and the analytical choices about endpoints which could significantly affect the input data, the results of the studies reviewed were contrasting from each other. Therefore, there was not enough evidence to show whether PCV-10 or PCV-13 was more cost-effective to be included into the NIP of children. Further research should be done on the sensitive variables of the cost-effectiveness ratio, as well as the local serotype distribution and disease burden should also be taken into account when planning the inclusion of PCVs into the NIP. / published_or_final_version / Public Health / Master / Master of Public Health

BACKGROUND: Despite the current recommendation by the Centre for Health Protection (CHP)of Hong Kong for adults aged 65 years or above to receive 23-valent pneumococcal polysaccharide vaccine (PPV23), pneumococcal disease(PD) has become the second leading causes of death in Hong Kong. A relatively new pneumococcal vaccine –13-valent pneumococcal conjugate vaccine (PCV13) was approved by the US Food and Drug Administration (FDA) in December 2011 and the European Medicines Agency (EMA) in July 2013 for the prevention of invasive disease caused by S. pneumoniae for older adults aged 50 years or above. It was shown to overcome some of the limitations of PPV23and potentially confer benefits to older adults in the prevention of PD. OBJECTIVES: To systematically review available literatures to examine whether PCV13 is superior to PPV23 or no vaccination in terms of the cost-effectiveness in the prevention of PD in older adults aged 50 years or above. METHODS: Two databases, PubMed and ISI Web of Science, were used to search for published journals. The year range of search in these databases was confined to10 years. RESULTS: A total of 318studies were identified initially and 10studies were included in this systematic review. Studies were conducted in the US, Colombia and European Union (EU) countries e.g. Italy, Germany, Netherlands and Spain. Different perspectives including societal, payer and health system were considered. The use of PCV13 was compared to either PPV23 or no vaccination in older adults aged 50 years or above. The coverage of PCV13 ranged from 42.4% to 70%, conferring an efficacy between 58% and 93.9%. The cost-effectiveness of PCV13 was expressed through the number of avoided cases/deaths for PD including invasive pneumococcal disease(IPD), inpatient and outpatient community-acquired pneumonia (CAP) as well as the incremental cost-effectiveness ratios (ICERs),either in cost per quality-adjusted life-year (QALY) gained or cost per life-year gained (LYG).Overall, PCV13 is shown to avoid more pneumococcal cases compared to PPV23 or no vaccination and is cost-effective in older adults aged 50 years of above. CONCLUSION: PCV13 is considered to be more cost-effective in older adults compared to PPV23 or no vaccination based on the current systematic review. Randomized controlled trials and cost-effectiveness evaluations are suggested to be conducted in Hong Kong and Asia-specific regions in order to obtain clinical and economic data of PCV13 in the Asian population. Policy-makers should also consider the effects of serotype replacement on the change in serotype distribution in local setting from time to time so that vaccines with appropriate serotype formulations could be researched. / published_or_final_version / Public Health / Master / Master of Public Health

Thesis (doctoral)--Lund University, 1995. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1995. / Added t.p. with thesis statement inserted.

No description available.

No description available.

No description available.