Lives, and lets live

Vaccine not requiring costly preservation process developed

Published: Tuesday 30 November 2004

Wonder vaccines: their active< (Credit: Cambridge Biostability)researchers have evolved a technology to manufacture vaccines that do not need to be refrigerated. The feat may enable additional vaccination of 10 million children every year, claim officials of the uk-based Cambridge Biostability, which will manufacture the vaccine in collaboration with Panacea Biotec, New Delhi. The vaccine will simultaneously work against diphtheria, tetanus, whopping cough, hepatitis b and a form of meningitis.

Worldwide, about two million children die every year from vaccine-preventable diseases; at the same time, up to half the vaccines get damaged because of temperature-induced changes.

The key to the new technique is encasing the active ingredients of a vaccine in a sugary coat, which preserves them even at a temperature of 60c. The coating is made from natural sugars (like raffinose) and an amino acid. These form transparent, spherical glass-like balls that are about three micrometres in diameter. These balls are suspended in an inert liquid, which prevents bacteria from spoiling the vaccine. When injected, the sugary balls dissolve, releasing the active ingredients.

For combination vaccines, the technology has another advantage. Each active ingredient can be coated before being mixed together, ensuring they do not interfere with each others' function as is the case with conventional vaccines. The balls can also be tweaked to make sure they dissolve at different rates, allowing booster doses that are normally given separately. The company's ultimate aim is to produce a single vaccine against the 12 major childhood diseases targeted by the World Health Organization (who). The company will also produce vaccines against potential bioweapons for the us government.

The who says the approach is promising, but the key question is whether its advantages outweigh the costs. "The cost is yet to be determined. Before this, we must look beyond the technology and ask whether it will become too expensive, especially for the developing countries, who should benefit the most from the feat," says Martin Friede, a vaccine specialist at who.

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