929 resultados para Vaccination coverage
Resumo:
Recently, there has been much speculation about the impact of international media coverage of Australia's position on Indigenous people, migrants and asylum seekers on other nations' images of Australia. In this experiment we examined whether there was any basis for such concerns by considering the short-term impact of negative TV coverage of Australians on Canadian viewers. A questionnaire provided baseline data on Canadian students' perceptions of Australians and Australian race relations. Four months later, the students were assigned to one of three conditions that varied media contact with Australians. Students viewed one of two television programs (about right-wing political independent, Pauline Hanson, and her emotive criticisms of Aborigines and Asian immigrants or about an ethnically-mixed group of young Australians and their positive sense of cultural identity), or they viewed no program (no contact control). Results indicated that both positive and negative media coverage of Australians affected Canadians' views of Australia in the short-term. In particular, negative coverage (of Hanson) promoted less favourable views of Australians and Australian race relations over time and relative to the positive media and no media control conditions. The media's role in shaping international images is discussed.
Resumo:
The prevalence rate of hepatitis B virus (HBV) infection in Pacific Island countries is amongst the highest in the world. Hepatitis B immunisation has been incorporated into national programmes at various times, often with erratic supply and coverage, until a regionally co-ordinated programme, which commenced in 1995 ensured adequate supply. The effectiveness of these programmes was recently evaluated in four countries, Vanuatu and Fiji in Melanesia, Tonga in Polynesia and Kiribati in Micronesia. That evaluation established that the programmes had a substantial beneficial impact in preventing chronic hepatitis B infection [Vaccine 18 (2000) 3059]. Several studies of hepatitis B vaccination programmes in endemic countries have identified the potential significance of surface gene mutants as a cause for failure of immunisation. In the study outlined in this paper, we screened infected children and their mothers for the emergence and prevalence of these variants in specimens collected from the four country evaluation. Although the opportunity for the emergence of HBV vaccine escape mutants in these populations was high due to the presence of a considerable amount of the virus in the population and the selection pressure from vaccine use, there were no a determinant vaccine escape mutants found. This suggests that vaccine escape variants are not an important cause for failure to prevent HBV transmission in this setting. Other HBsAg variants were detected, but their functional significance remains to be determined. The failure to provide satisfactory protection during such immunisation programmes reflects the need for achieving and sustaining high vaccine coverage, improving the timeliness of doses as well as improving 'cold-chain' support, rather than the selection of vaccine-escape mutants of HBV. (C) 2004 Elsevier Ltd. All rights reserved.
Resumo:
A subset of human papillomaviruses (HPVs) promote anogenital malignancy, including cervical cancer, and prevention and treatment strategies that reflect the causal role of HPV are being developed. Vaccines based on HPV virus-like particles induce genotype-specific virus-neutralizing antibody and prevent infection with HPV1. Persistent papillomavirus infection is required for the development of papillomavirus-associated cancer and, therefore, therapeutic vaccines are being developed to eliminate established papillomavirus infection. Such vaccines test principles for the growing field of tumour-antigen-specific immunotherapy. This article reviews progress in the field and draws conclusions for the development of future prophylactic and therapeutic viral vaccines.
Resumo:
Using native chemical ligation, we synthesized a group A streptococcal. (GAS) vaccine that contained three different GAS M protein peptide epitopes in a chemically well-characterized construct in high purity. Two of the peptide epitopes represented variable amino terminal serotype determinants, and the third represented a carboxyl terminal conserved region determinant of the GAS M protein. We also synthesized a lipid core peptide (LCP) construct containing the same three peptides. Upon immunization of mice, the non-LCP construct only elicited antibody responses to all three epitopes with the use of adjuvant. The LCP construct, however, elicited excellent antibody responses to all three epitopes without the need for any additional adjuvant or carrier. We have synthesized the LCP synthetic vaccine system with good reproducibility.
Resumo:
We have investigated the lipid polylysine core peptide (LCP) system as a self-adjuvanting group A streptococcal (GAS) vaccine delivery approach. LCP constructs were synthesised incorporating peptides from the M protein conserved carboxy terminal C-repeat region, the amino terminal type-specific region and from both of these regions. Immunisation with the constructs without adjuvant led to the induction of peptide-specific serum IgG antibody responses, heterologous opsonic antibodies, and complete protection from GAS infection. These data indicate that protective immunity to GAS infection can be evoked using the self-adjuvanting LCP system, and point to the potential application of this system in human mucosal GAS vaccine development. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
We have previously constructed an acapsular Pasteurella multocida X-73 (serogroup A) mutant strain which was attenuated in virulence for chickens (Chung JY, Wilkie IW, Boyce JD, Townsend KM, Frost AJ, Ghodussi M, Adler B. Role of capsule in the pathogenesis of fowl cholera caused by Pasteurella multocida serogroup A. Infect. Immun. 2001;69:2487-2492). In this study, we have assessed the ability of this acapsular strain (PBA930) to induce protection against wild-type challenge in mice and the natural host chickens. Intramuscular administration of PBA930 to mice stimulated significant protection against X-73 and the heterologous strain P-1059 (A:3), but not against challenge with P-1662 (A:4). No protection was observed when PBA930 was introduced by the intraperitoneal or subcutaneous routes in mice. Significantly, the acapsular strain PBA930 was able to induce protection against challenge with wild type X-73 in chickens. (c) 2004 Elsevier Ltd. All rights reserved.
Resumo:
Human metapneumovirus (hMPV) has emerged as an important human respiratory pathogen causing upper and lower respiratory tract infections in young children and older adults. In addition, hMPV infection is associated with asthma exacerbation in young children. Recent epidemiological evidence indicates that hMPV may cocircullate with human respiratory syncytial virus (hRSV) and mediate clinical disease similar to that seen with hRSV. Therefore, a vaccine for hMPV is highly desirable. In the present study, we used predictive bioinformatics, peptide immunization, and functional T-cell assays to define hMPV cytotoxic T-lymphocyte (CTL) epitopes recognized by mouse T cells restricted through several major histocompatibility complex class I alleles, including HILA-A*0201. We demonstrate that peptide immunization with hMPV CTL epitopes reduces viral load and immunopathollogy in the lungs of hMPV-challenged mice and enhances the expression of Th1-type cytokines (gamma interferon and interleukin-12 [IL-12]) in lungs and regional lymph nodes. In addition, we show that levels of Th2-type cytolkines (IL-10 and IL-4) are significantly lower in hMPV CTL epitope-vaccinated mice challenged with hMPV. These results demonstrate for the first time the efficacy of an hMPV CTL epitope vaccine in the control of hMPV infection in a murine model.
Resumo:
A challenge in epidermal DNA vaccination is the efficient and targeted delivery of polynucleotides to immunologically sensitive Langerhans cells. This paper investigates this particular challenge for physical delivery approaches. The skin immunology and material properties are examined in the context of the physical cell targeting requirements of the viable epidermis. Selected current physical cell targeting technologies engineered to meet these needs are examined: needle and syringe; diffusion patches; liquid jet injectors; microneedle arrays/patches; and biolistic particle injection. The operating methods and relative performance of these approaches are discussed, with a comment on potential future developments and technologies. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
Benchmarking of the performance of states, provinces, or districts in a decentralised health system is important for fostering of accountability, monitoring of progress, identification of determinants of success and failure, and creation of a culture of evidence. The Mexican Ministry of Health has, since 2001, used a benchmarking approach based on the World Health Organization (WHO) concept of effective coverage of an intervention, which is defined as the proportion of potential health gain that could be delivered by the health system to that which is actually delivered. Using data collection systems, including state representative examination surveys, vital registration, and hospital discharge registries, we have monitored the delivery of 14 interventions for 2005-06. Overall effective coverage ranges from 54.0% in Chiapas, a poor state, to 65.1% in the Federal District. Effective coverage for maternal and child health interventions is substantially higher than that for interventions that target other health problems. Effective coverage for the lowest wealth quintile is 52% compared with 61% for the highest quintile. Effective coverage is closely related to public-health spending per head across states; this relation is stronger for interventions that are not related to maternal and child health than those for maternal and child health. Considerable variation also exists in effective coverage at similar amounts of spending. We discuss the implications of these issues for the further development of the Mexican health-information system. Benchmarking of performance by measuring effective coverage encourages decision-makers to focus on quality service provision, not only service availability. The effective coverage calculation is an important device for health-system stewardship. In adopting this approach, other countries should select interventions to be measured on the basis of the criteria of affordability, effect on population health, effect on health inequalities, and capacity to measure the effects of the intervention. The national institutions undertaking this benchmarking must have the mandate, skills, resources, and independence to succeed.