Vaccine
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This review discusses recent progress in the development of a vaccine against Helicobacter pylori. This progress includes demonstration that: effective immunisation is independent of antibodies but dependent upon CD4+ T helper cells, although their role remains unknown; the immunisation regime can be improved to increase efficacy; successful immunisation against H. pylori is possible using a live vector; a strain of H. pylori suitable for experimental infection of humans has been developed. Important issues that remain to be addressed include incomplete protection, non-availability of suitable mucosal adjuvants and post-immunisation gastritis. Significantly, commercial development of products for clinical trial is underway.
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The economics of vaccinating restaurant workers against hepatitis A were studied using Monte Carlo simulation models, one with a restaurant-owner perspective, and one with a societal perspective. The restaurant model allowed for a different size, number of employees and employee turnover rate. Benefits were the avoidance of loss of business (including the possibility of bankruptcy) after publicity linking the restaurant to an outbreak associated with a case of hepatitis A in a food handler. ⋯ Even a 75% probability of bankruptcy still resulted in negative NPVs at the 95th percentiles. For society, vaccination was only cost-saving (i.e. positive NPV) if done only during epidemics and if it cost < $20/employee. Vaccinating restaurant employees is unlikely to be economical from either the restaurant owner or the societal perspective, even during hepatitis A epidemics.
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Randomized Controlled Trial Clinical Trial
Measles antibody responses after early two dose trials in Guinea-Bissau with Edmonston-Zagreb and Schwarz standard-titre measles vaccine: better antibody increase from booster dose of the Edmonston-Zagreb vaccine.
In Guinea-Bissau, children were randomised at 6 months of age to receive either two doses of standard-titre measles vaccine at 6 and 9 months of age or an inactivated polio vaccine at 6 months and standard-titre measles vaccine at 9 months of age. During the first 5 months, children received Edmonston-Zagreb (EZ) vaccine and during the following 11 months, the Schwarz (SW) vaccine. Five percent of the mothers, 74% of children at 6 months of age, and 92% of unvaccinated children at 9 months of age had unprotective levels (<125 mIU/ml) of measles antibodies. ⋯ Conclusively, after two doses of EZ measles vaccine more children were protected at 18 months of age than after two doses of SW. One dose of SW provided the highest antibody response, but a higher proportion of unprotected than one or two doses of EZ. The EZ vaccine was less sensitive to maternal antibodies, and able to increase the antibody response by revaccination, while the second SW vaccine resulted in an unchanged or lower antibody response.
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It is expected the world's vaccine market will show a robust growth over the next few years, yet this growth will predominantly come from introduction of new vaccines in industrialised countries. Economic market forces will increasingly direct vaccine sales and vaccine development towards the needs of markets with effective purchasing power. ⋯ Such measures must help developing countries to get access to future vaccines for diseases that predominantly or exclusively affect them, but for which the poor economic prospects do not provide a basis for the vaccine industry to undertake costly research and development programmes. Recent initiatives such as GAVI, including the establishment of a reliable, guaranteed purchase fund, could provide a solution to the problem.