Vaccine
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Only viruses of the Influenzavirus A genus have been isolated from birds and termed avian influenza [AI] viruses, but viruses with all 16 haemagglutinin [H1-H16] and all 9 neuraminidase [N1-N9] influenza A subtypes in the majority of possible combinations have been isolated from avian species. Influenza A viruses infecting poultry can be divided into two groups. The very virulent viruses causing highly pathogenic avian influenza [HPAI], with flock mortality as high as 100%. ⋯ Since the 1990s AI infections due to two subtypes have been widespread in poultry across a large area of the World. LPAI H9N2 appears to have spread across the whole of Asia in that time and has become endemic in poultry in many of the affected countries. However, these outbreaks have tended to have been overshadowed by the H5N1 HPAI virus, initially isolated in China, that has now spread in poultry and/or wild birds throughout Asia and into Europe and Africa, resulting in the death or culling of hundreds of millions of poultry and posing a significant zoonosis threat.
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There are claims that immunisations cause sudden infant death syndrome (SIDS), but some studies have found either no association or that they are associated with a reduced risk of SIDS. ⋯ Immunisations are associated with a halving of the risk of SIDS. There are biological reasons why this association may be causal, but other factors, such as the healthy vaccinee effect, may be important. Immunisations should be part of the SIDS prevention campaigns.
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The dangers of accidental freezing of vaccines in the cold chain have prompted studies throughout the globe to better characterize the risk. To date, there has been no systematic review of these studies. ⋯ More rigorous study designs were associated with higher levels of freeze exposure. As more expensive, freeze-sensitive vaccines are introduced into immunization schedules, freeze prevention will become increasingly critical for ensuring that the world's children are receiving fully potent vaccine.
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This paper offers a framework for managing a comprehensive Global Access Strategy for new vaccines in developing countries. It is aimed at strengthening the ability of public-sector entities to reach their goals. ⋯ Relying on the application of innovation theory, the strategy leads to the identification of six Components of Innovation which cover all aspects of the vaccine innovation process. Appropriately modified, the proposed framework can be applied to the development and introduction of other products in developing countries including drugs, and nutritional and agricultural products.
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Influenza A/H5N1 (avian influenza) has now caused 258 human infections (as of November 13, 2006), with an approximate 50% mortality rate. Because the virus is novel in terms of antigenic type and causes infection and illness, and because humans have no pre-existing immunity, the conditions for a possible pandemic exist. ⋯ This brief overview will review basic virologic, immunologic and epidemiologic information relevant to understanding and preparing for this threat. In particular, the role of avian influenza vaccines will be reviewed.