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  3. Monday, 08 November 2004
POST 00724E : COOL TECHNOLOGY : THE END OF THE COLD-CHAIN? 8 November 2004 _____________________________________ Below is an article published in "The Economist". The delay in posting it was due to the translating into French. Do not dwell on the few simplifications or generalizations of a journalistic nature. It is the essence that counts! This article has also been added in both languages to the "General News" sub-page of our site at : ____________________________________ From The Economist, Oct 21st 2004, print edition SCIENCE AND TECHNOLOGY : A trick from nature could help vaccinate millions of poor children IMMUNISATION is a pain, and not just for those lucky enough to get a shot in the arm. Vaccines themselves, which are made largely out of protein, have to be refrigerated to prevent them going off. Keeping vaccines at the right temperature on their long journey from the factory in, say, Europe to a village in sub-Saharan Africa is a costly and complex business. Experts estimate that almost half of all vaccine doses are wasted because of temperature damage, which is cold comfort to the families of the 2m children in poor countries who die every year from measles and other vaccine-preventable diseases. Cambridge Biostability, a British biotechnology firm, may have found a solution by borrowing a trick from nature. Some plants, and even insects, are able to survive hundreds of years in suspended animation through a process called anhydrobiosis. Faced with drought, their tissues produce sugars which turn into a syrup as they start to dry out, eventually forming a sort of glass which preserves them perfectly. Add water, and these organisms spring back to life. Scientists at Cambridge Biostability have adapted this technique to vaccines. First, they coat clusters of vaccine molecules with a sugar spray. Then they dry them in such a way that they form tiny glassy beads. These sugar "microspheres" are then suspended in a non-water-containing liquid, which keeps them intact until they are injected into the body. There, the sugar dissolves in the blood and the vaccine is released. The advantage of this is that the microspheres can survive temperatures as high as 55°C for months, conditions that destroy normal vaccines. Tests in mice and guinea pigs have shown that such vaccine microspheres are as safe and effective as conventional shots. The developers point to other advantages, too. Even though conventional vaccines are transported as dry powder rather than in solution, they still need to be dissolved in water before injection. That can lead to bacterial contamination or worse if the wrong sort of liquid is used. The new vaccine microspheres, on the other hand, can be injected straight into the body, eliminating those sorts of mistake and with them the need for the preservatives found in ordinary vaccines. In addition to that, because the sugar-glass coats the vaccine molecules and thus isolates them, various vaccines in their own microspheres can be mixed together in a single jab. This is something that is hard to do with conventional shots, since different vaccine molecules will react together unless insulated from one other. Cambridge Biostability, with support from Britain's Department for International Development and the Programme for Appropriate Technology in Health, an American not-for-profit group, is working on a sugar-glass version of a combined shot against five nasty childhood diseases, including diphtheria and meningitis. The next step is to test the new formulation in human volunteers, which will be done in India by the firm's commercial partner, Panacea Biotec, based in Delhi. If all goes well, the vaccine could be on the market in three years' time. By eliminating the need for refrigeration, the technology could save up to $300m a year in global vaccine costs, which means another 10m poor children could be protected. Moreover, the technique may also work with other protein-based drugs, such as insulin. Sugar-glass could one day prove one of biotech's sweetest successes. ______________________________________________________________________________ Visit the TECHNET21 Website at You will find instructions to subscribe, a direct access to archives, links to reference documents and other features. ______________________________________________________________________________ To UNSUBSCRIBE, send a message to : Leave the subject area BLANK In the message body, write unsubscribe TECHNET21E ______________________________________________________________________________ The World Health Organization and UNICEF support TechNet21. The TechNet21 e-Forum is a communication/information tool for generation of ideas on how to improve immunization services. It is moderated by Claude Letarte and is hosted in cooperation with the Centre de coopération internationale en santé et développement, Québec, Canada ( ______________________________________________________________________________

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