Coverage of pilot parenteral vaccination campaign against canine rabies in N'Djamena, Chad.
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Canine rabies, and thus human exposure to rabies, can be controlled through mass vaccination of the animal reservoir if dog owners are willing to cooperate. Inaccessible, ownerless dogs, however, reduce the vaccination coverage achieved in parenteral campaigns. This study aimed to estimate the vaccination coverage in dogs in three study zones of N'Djamena, Chad, after a pilot free parenteral mass vaccination campaign against rabies. We used a capture-mark-recapture approach for population estimates, with a Bayesian, Markov chain, Monte Carlo method to estimate the total number of owned dogs, and the ratio of ownerless to owned dogs to calculate vaccination coverage. When we took into account ownerless dogs, the vaccination coverage in the dog populations was 87% (95% confidence interval (CI), 84-89%) in study zone I, 71% (95% CI, 64-76%) in zone II, and 64% (95% CI, 58-71%) in zone III. The proportions of ownerless dogs to owned dogs were 1.1% (95% CI, 0-3.1%), 7.6% (95% CI, 0.7-16.5%), and 10.6% (95% CI, 1.6-19.1%) in the three study zones, respectively. Vaccination coverage in the three populations of owned dogs was 88% (95% CI, 84-92%) in zone I, 76% (95% CI, 71-81%) in zone II, and 70% (95% CI, 66-76%) in zone III. Participation of dog owners in the free campaign was high, and the number of inaccessible ownerless dogs was low. High levels of vaccination coverage could be achieved with parenteral mass vaccination. Regular parenteral vaccination campaigns to cover all of N'Djamena should be considered as an ethical way of preventing human rabies when post-exposure treatment is of limited availability and high in cost. (+info)
Meningococcal meningitis in sub-Saharan Africa: the case for mass and routine vaccination with available polysaccharide vaccines.
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Endemic and epidemic group A meningococcal meningitis remains a major cause of morbidity and mortality in sub-Saharan Africa, despite the availability of the safe and inexpensive group A meningococcal polysaccharide vaccine, which is protective at all ages when administered as directed. Despite optimal therapy, meningococcal meningitis has a 10% fatality rate and at least 15% central nervous system damage. WHO's policy of epidemic containment prevents, at best, about 50% of cases and ignores endemic meningitis, which is estimated at 50,000 cases per year. The effectiveness of group A, C, W135, and Y capsular polysaccharides is the basis for recommending universal vaccination with group A meningococcal polysaccharide twice in infancy, followed by the four-valent vaccine in children aged two and six years. This could eliminate epidemic and endemic disease, prepare for the use of conjugates when they become available, and probably could have prevented the recent epidemics of groups A and W135 meningitis in Burkina Faso. (+info)
Smallpox and bioterrorism.
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Smallpox was declared to be eradicated on 8 May 1980, during the Thirty-third World Health Assembly. However, concerns about the possible use of the virus as a weapon of bioterrorism have increased in recent years. Governments have responded by initiating selective vaccination programmes and other public health measures. This review uses historical data from 20th century outbreaks to assess the risks to current populations (which have declining immunity) from a deliberate release of virus. The data presented supports the conclusion of a previous reviewer (Mack) that "smallpox cannot be said to live up to its reputation. Far from being a quick-footed menace, it has appeared as a plodding nuisance with more bark than bite." Its R value (the average number of secondary cases infected by a primary case) is lower than that for measles, human parvovirus, chickenpox, mumps, rubella, and poliomyelitis; only the value for severe acute respiratory syndrome (SARS) is lower. Like SARS, close person-to-person contact is required for effective spread of the disease, and exposure to the virus in hospitals has played an important role in transmission for both viruses. In the present paper the dangers of mass vaccination are emphasized, along with the importance of case isolation, contact tracing, and quarantine of close contacts for outbreak control. The need for rapid diagnosis and the continued importance of maintaining a network of electron microscopes for this purpose are also highlighted. (+info)
Pneumococcal vaccination for the elderly in The Netherlands? Assessment of the quality and content of available comparative studies.
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BACKGROUND: A question that is currently topical in the Netherlands is whether it makes sense to introduce on a national scale vaccination against pneumococcal infections for elderly people who are at present receiving the influenza vaccination. We recently studied the scientific literature on the subject in an attempt to answer this question. METHODS: We searched for systematic reviews (SRs), randomised clinical trials (RCTs) and cohort studies in MEDLINE, EMBASE, the Cochrane Library, Current Controlled Trials and via Google (period 1966 to June 2002). The SRs and RCTs were assessed with a methodological checklist. RESULTS: We identified four SRs, two trials (of which one was pseudo-random) and one retrospective cohort study. The methodological quality of the SRs was reasonable and in this respect differed little among themselves. The SRs differed strongly with regard to subgroups, outcome measures, valency of vaccines, duration of follow-up and combination with influenza vaccination. The SRs showed that vaccination has more effect in low-risk groups, does not appear to be effective in high-risk patients and the elderly and is more effective in nonindustrialised countries. The outcomes based on the various outcome measures showed major differences. The three studies into the effectiveness of the pneumococcal vaccination in the elderly all showed major methodological shortcomings. For the majority of outcome measures the outcomes were negative. CONCLUSION: There is insufficient convincing evidence in favour of the introduction of the pneumococcal vaccination as a supplement to influenza vaccination for the elderly. It seems as if (international) opinion had already been fully formed before published studies and systematic reviews become available in the last few years. It is perhaps worth considering setting up a prospective trial in the elderly Dutch population. (+info)
Mass smallpox vaccination and cardiac deaths, New York City, 1947.
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In April 1947, during a smallpox outbreak in New York City (NYC), more than 6 million people were vaccinated. To determine whether vaccination increased cardiac death, we reviewed NYC death certificates for comparable periods in 1946, 1947, and 1948 (N = 81,529) and calculated adjusted relative death rates for the postvaccination period. No increases in cardiac deaths were observed. (+info)
Initial experience with mass immunization as a bioterrorism countermeasure.
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Anthrax vaccine was administered to approximately 5000 individuals at a deployed location near Iraq in a 1-week period. This report describes the planning and administrative process to initiate such a program, with a snapshot view of the first week of immunization. Compliance with this program was important to best protect troops in this high-threat region. The authors share their experience and detail the process of handling refusals, as these are most likely to reveal themselves at the beginning of an immunization program. The program resulted in a compliance rate of 98%. With increased terrorist threats and widespread availability of biologic agents of mass destruction, experiences with such immunization programs should be described in the literature and analyzed in anticipation of similar programs in the future. (+info)
Vaccines administered simultaneously: directions for new combination vaccines based on an historical review of the literature.
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OBJECTIVES: The recognized benefits of administering vaccines simultaneously has encouraged vaccine producers to develop combination vaccines. If contemporary research and development can realize vaccines that achieve the current standards for safety, immunogenicity, and efficacy, other specific vaccine associations may also merit reconsideration as combination vaccines. METHODS: An historical review of the vaccine association literature reveals two important themes: first, the programs of mass vaccination, in particular, the eradication of smallpox, sessions where multiple vaccines (other than the smallpox vaccine) were given concurrently, and the Expanded Programme on Immunization (EPI); and, second, the domain of travel vaccines, including travellers to a disease-endemic country (such as migrants, tourists, military personnel, or expatriates) and WHO requirements for international travellers. RESULTS/CONCLUSIONS: Based on this historical review, combination vaccines worth reconsideration could fill epidemiologic niches in the EPI with, for instance, a measles--yellow fever, a measles--Japanese encephalitis or a pertussis-based paediatric combination rabies vaccine. Furthermore, other combinations could broaden protection against the pathogens responsible for meningitis, pneumonia, or enteric diseases. Nevertheless, complex issues such as necessity, feasibility, or affordability will ultimately determine if any one of these becomes a combination vaccine. (+info)
The Global Alliance for Vaccines and Immunization: is it a new model for effective public-private cooperation in international public health?
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The Global Alliance for Vaccines and Immunization (GAVI) has in many ways been remarkably successful in revitalizing the international coalition of institutions and organizations concerned with getting vaccines to the children of the poorest countries. Many have seen this high-profile venture in public-private cooperation as a model for other groups concerned with more effectively helping to solve health problems in the developing world. We examined major flaws in the GAVI and argue that in fact the alliance does not represent a new paradigm for international public health. However, the experience of the GAVI may suggest an alternative, and more effective, way to conceptualize future global initiatives. (+info)