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R B Aylward

Publications and source records attributed to R B Aylward.

At least 19 recordsLinked to original sources
PubMed2000

Disease eradication as a public health strategy: a case study of poliomyelitis eradication.

Disease eradication as a public health strategy was discussed at international meetings in 1997 and 1998. In this article, the ongoing poliomyelitis eradication initiative is examined using the criteria for evaluating candidate diseases for eradication proposed at these meetings, which covered costs and benefits, biological determinants of eradicability (technical feasibility) and societal and political considerations (operational feasibility). The benefits of poliomyelitis eradication are shown to include a substantial investment in health services delivery, the elimination of a major cause of disability, and far-reaching intangible effects, such as establishment of a "culture of prevention". The costs are found to be financial and finite, despite some disturbances to the delivery of other health services. The "technical" feasibility of poliomyelitis eradication is seen in the absence of a non-human reservoir and the presence of both an effective intervention and delivery strategy (oral poliovirus vaccine and national immunization days) and a sensitive and specific diagnostic tool (viral culture of specimens from acute flaccid paralysis cases). The certification of poliomyelitis eradication in the Americas in 1994 and interruption of endemic transmission in the Western Pacific since March 1997 confirm the operational feasibility of this goal. When the humanitarian, economic and consequent benefits of this initiative are measured against the costs, a strong argument is made for eradication as a valuable disease control strategy.

Developed Countries↗
PubMed2000

Eradication of poliomyelitis in countries affected by conflict.

The global initiative to eradicate poliomyelitis is focusing on a small number of countries in Africa (Angola, Democratic Republic of the Congo, Liberia, Sierra Leone, Somalia, Sudan) and Asia (Afghanistan, Tajikistan), where progress has been hindered by armed conflict. In these countries the disintegration of health systems and difficulties of access are major obstacles to the immunization and surveillance strategies necessary for polio eradication. In such circumstances, eradication requires special endeavours, such as the negotiation of ceasefires and truces and the winning of increased direct involvement by communities. Transmission of poliovirus was interrupted during conflicts in Cambodia, Colombia, El Salvador, Peru, the Philippines, and Sri Lanka. Efforts to achieve eradication in areas of conflict have led to extra health benefits: equity in access to immunization, brought about because every child has to be reached; the revitalization and strengthening of routine immunization services through additional externally provided resources; and the establishment of disease surveillance systems. The goal of polio eradication by the end of 2000 remains attainable if supplementary immunization and surveillance can be accelerated in countries affected by conflict.

Adolescent↗
PubMed1999

Poliomyelitis eradication.

Since the poliomyelitis eradication program began in 1988, the number of poliovirus infected continents and countries have decreased from five to two and from greater than 100 to 53, respectively. A nearly 90% reduction in the incidence of polio has been achieved with a corresponding decrease in virus genomic heterogeneity. Major challenges to eradication remain in south Asia and Africa in those areas with hot and humid climates, high population density, and high birth rates. Of particular concern are countries with ongoing social unrest and poor health infrastructure. With the approaching eradication of polio, post-eradication issues are now being addressed. The World Health Organization (WHO) draft plan for containment of wild polioviruses has been published for comment. Commissions and committees for certification of eradication have been established. Still under discussion is the question of the appropriate strategy for stopping oral polio vaccine (OPV) immunization. Studies are underway to determine whether vaccine-derived polioviruses will continue to circulate after OPV cessation and the potential disease consequences of that circulation.

Africa↗
PubMed1998

Certifying the elimination of poliomyelitis from Europe: advancing towards global eradication.

UNLABELLED: Indigenous wild polioviruses have been virtually eliminated from the 51 countries of the European Region of the World Health Organization (WHO), an achievement that is of critical importance to the global initiative to eradicate poliomyelitis by the year 2000. An international commission has been established to certify the elimination of poliomyelitis from this region. European countries have recently been requested to establish National Certification Committees to review and submit the necessary documentation and surveillance data. In some Western European countries where polio has not been reported for many years, the challenge will be to produce robust evidence demonstrating both the current absence of wild poliovirus and the means to promptly detect and respond to possible importations of wild poliovirus for the next several years, up to global eradication and the cessation of polio vaccination. KEY MESSAGES: 1. laboratory-based surveillance with collection of faecal specimens is necessary to demonstrate the absence of indigenous wild poliovirus 2. certification can only occur after all countries have demonstrated the absence of indigenous wild polioviruses for at least 3 years and have the means to detect and respond to importations of wild poliovirus for several years into the future 3. any single case of poliomyelitis in Europe now requires an immediate public health response which includes virological investigation and prompt notification to the World Health Organization.

Certification↗
PubMed1998

Outbreak of paralytic poliomyelitis in Albania, 1996: high attack rate among adults and apparent interruption of transmission following nationwide mass vaccination.

After >10 years without detection of any cases of wild virus-associated poliomyelitis, a large outbreak of poliomyelitis occurred in Albania in 1996. A total of 138 paralytic cases occurred, of which 16 (12%) were fatal. The outbreak was due to wild poliovirus type 1, isolated from 69 cases. An attack rate of 10 per 100,000 population was observed among adults aged 19-25 years who were born during a time of declining wild poliovirus circulation and had been vaccinated with two doses of monovalent oral poliovirus vaccines (OPVs) that may have been exposed to ambient temperatures for prolonged periods. Control of the epidemic was achieved by two rounds of mass vaccination with trivalent oral poliovirus vaccine targeted to persons aged 0-50 years. This outbreak underscores the ongoing threat of importation of wild poliovirus into European countries, the importance of delivering potent vaccine through an adequate cold chain, and the effectiveness of national OPV mass vaccination campaigns for outbreak control.

Adolescent↗
PubMed1998

Perspectives from the global poliomyelitis eradication initiative.

Ten years after the year 2000 target was set by the World Health Assembly, the global poliomyelitis eradication effort has made significant progress towards that goal. The success of the initiative is built on political commitment within the endemic countries. A partnership of international organizations and donor countries works to support the work of the countries. Interagency coordinating committees are used to ensure that all country needs are met and to avoid duplication of donor effort. Private sector support has greatly expanded the resources available at both the national and international level. At the programmatic level, rapid implementation of surveillance is the key to success, but the difficulty of building effective surveillance programmes is often underestimated. Mass immunization campaigns must be carefully planned with resources mobilized well in advance. Programme strategies should be simple, clear and concise. While improvements in strategy and technology should be continuously sought, changes should be introduced only after careful consideration. Careful consideration should be given in the planning phases of a disease control initiative on how the initiative can be used to support other health initiatives.

Global Health↗
PubMed1997

The impact of immunization control activities on measles outbreaks in middle and low income countries.

BACKGROUND: The World Health Organization recommended strategy for responding to measles outbreaks in developing countries does not promote the use of immunization campaigns due to their high cost, disruptive nature and limited impact. Given the substantial morbidity and mortality associated with such outbreaks, a literature review was conducted as a basis for re-evaluating this policy. METHODS: Reports of supplementary immunization activities that were performed to control measles outbreaks in middle or low income countries were identified. The impact of the immunization activities on the course of each outbreak was evaluated by examining the data provided. RESULTS: Of 66 reports detailing a measles outbreak in a middle or low income country, 17 described supplementary immunization activities which included seven 'non-selective' immunization campaigns, three 'selective' campaigns and one use of an early 2-dose schedule. Eight of the reports commented on the impact of the response, five of which reported a reduction in outbreak morbidity. Only one of the reports, from an isolated island outbreak, provided sufficient data to support a possible reduction in outbreak-associated morbidity. CONCLUSIONS: There are limited data on the impact of measles outbreak immunization activities from developing countries. The available data do not support a change in the WHO recommended strategy for conducting a limited, if any, immunization response to such outbreaks. Immunization strategies which aim to prevent outbreaks may be more effective than campaigns to interrupt transmission of an outbreak which has already begun.

Child↗
PubMed1997

Development and coordination of the Polio Laboratory Network in the Western Pacific Region of the World Health Organization.

A multitiered network of polio laboratories, consisting of specialized reference laboratories, regional reference laboratories, national laboratories and, in the case of China, provincial laboratories, was established in the Western Pacific Region of the World Health Organization (WHO) in 1992. The network currently consists of 43 laboratories within the Region and is coordinated through the WHO Regional Office in Manila. As the levels and extent of supplementary immunization and acute flaccid paralysis surveillance activities have increased, so has the work load of network laboratories. The total number of stool specimens collected and processed in Polio Laboratory Network laboratories in this WHO region in 1995 exceeded 15,000. With the Region now establishing the criteria necessary for certification of polio-free status, it is essential for the Polio Laboratory Network to establish international confidence in its ability to carry out its role in the eradication of polio.

Asia, Southeastern↗
PubMed1997

Establishing acute flaccid paralysis surveillance under difficult circumstances: lessons learned in Cambodia.

The implementation of the World Health Organization's recommended strategies for polio eradication, particularly acute flaccid paralysis (AFP) surveillance, can be limited by difficult circumstances beyond the control of immunization personnel. In Cambodia, however, obstacles to establishing AFP surveillance were rapidly overcome using a strategy that improved reporting through active surveillance in a geographically limited area before gradually expanding to include the whole country. The success of the strategy was ensured by the timely provision of the resources that were needed to establish, expand, and monitor surveillance activities.

Cambodia↗
PubMed1997

National immunization days: state of the art.

National immunization days (NIDs) are nationwide mass campaigns to deliver supplemental doses of oral poliovirus vaccine to interrupt the circulation of wild polioviruses. They constitute one of the critical strategies for global poliomyelitis eradication and should be implemented in all countries with widespread poliovirus transmission. The certification of wild poliovirus eradication from the Western Hemisphere in September 1994 verified the effectiveness of this aspect of the World Health Organization's (WHO) overall strategy for polio eradication by the year 2000. NIDs require careful advanced planning and orchestration by each country. WHO provides specific guidelines for NIDs regarding the season, target age group, duration, frequency, inclusion of other interventions, vaccine delivery strategies, and evaluation. With strong routine immunization programs and the effective implementation of NIDs, "mop-up" campaigns, and acute flaccid paralysis surveillance, the goal of global polio eradication will be achieved.

Global Health↗
PubMed1997

The experience of countries in the Western Pacific Region in conducting national immunization days for poliomyelitis eradication.

Experience with national immunization days (NIDs) in six countries of the Western Pacific Region has shown that political support at all levels, detailed logistics plans, strategies appropriate to the local situation, and simple social mobilization messages have been key factors in the success of NIDs. Conventional strategies that may apply to conducting routine Expanded Programme on Immunization vaccinations do not necessarily apply to NIDs, in which the maximum number of children must be immunized in 1 or 2 days. Setting up temporary immunization posts at sites convenient to the local situation, moving the posts once or twice during the course of a day, and using volunteers to staff them are among many of the adaptations used successfully. Coverage figures published immediately after an NID can be misleading because of uncertainty about the true denominator. The true measure of the success of NIDs is in surveillance for wild poliovirus after the event.

Asia, Southeastern↗
PubMed1997

Strengthening routine immunization services in the Western Pacific through the eradication of poliomyelitis.

Infant immunization coverage in the Western Pacific Region of the World Health Organization was reviewed to evaluate the impact of polio eradication activities on routine immunization services. The trend in bacille Calmette-Guérin (one dose; BCG), diphtheria-tetanus toxoids-pertussis (three doses; DTP3), and measles (one dose) vaccination rates was analyzed from the beginning of eradication activities in 1990 to 1994 in the five polio-endemic countries that conducted supplementary oral polio vaccine immunization. In China and the Philippines, coverage for each antigen remained at or above 90% and 85%, respectively, while in Vietnam, coverage for all three antigens rose from 85% to 95%. BCG, DTP3, and measles vaccine coverage more than doubled in the People's Democratic Republic of Lao and increased by >30% in the Kingdom of Cambodia during the same period.

Asia, Southeastern↗
PubMed1997

Integrated disease control initiatives: polio eradication and neonatal tetanus elimination in Egypt.

Accelerated disease control initiatives, such as polio eradication by the year 2000, may substantially benefit public health programs in general. In Egypt, the control of other vaccine-preventable diseases, most noticeably neonatal tetanus (NT), has been facilitated by the polio eradication initiative. Linking NT reporting with the acute flaccid paralysis (AFP) surveillance system, which had been established for polio eradication, markedly improved the capacity to identify NT high-risk areas and target supplementary immunization activities appropriately. While the close integration of surveillance activities was to the benefit of both programs, mass immunization activities were not conducted simultaneously because of differences in the objectives, target populations, and operational aspects of oral polio vaccine and tetanus toxoid campaigns. In addition to substantial progress toward polio eradication in Egypt since 1988, there has been an 80% reduction in annual NT cases, in part due to the integration of appropriate aspects of these two disease control initiatives.

Adolescent↗
PubMed1997

The eradication of poliomyelitis in Egypt: critical factors affecting progress to date.

Poliomyelitis eradication activities in Egypt were reviewed to identify the critical factors for the progress seen by 1995 and to highlight problems that could be avoided in other countries in which poliomyelitis is endemic. National immunization and surveillance data demonstrate that the combination of high routine immunization coverage (>85%) with oral polio vaccine combined with two properly conducted rounds of national immunization days (NIDs) resulted in a 75% reduction in reported polio cases between 1992 and 1993. Available data suggest that earlier control strategies, such as single-round NIDs in 1990 and 1991, the administration of inactivated poliovirus vaccine (IPV) at 2 months of age in 1992-1993, and the use of "mop-up" campaigns while wild poliovirus was still widespread, did not contribute substantially to the recent decline in cases. Proper implementation of the World Health Organization's recommended strategies can eliminate wild poliovirus circulation in the large, densely populated tropical countries in which poliomyelitis remains endemic.

Egypt↗