Alternative sources for better and safer products |
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Improved hepatitis B vaccine
Hepatitis B is a serious viral infection, killing 2 million people per year and 300 million people being chronically infected. The disease spreads by contact with infected blood. The first vaccine against hepatitis B was made with purified Hepatitis B Surface Antigen (HBsAg), extracted from infected blood of chronic carriers. Such a procedure is complex, requires an inactivation step and poses the risk of possible contamination by other infectious agents. In 1986, the company SmithKline Beecham Biologicals succeeded in expressing the HBsAg gene into common baker's yeast, Saccharomyces cerevisiae. The antigen expressed is identical to the natural HBsAg in its proteinic structure and forms the basis for a vaccine that is much safer to manufacture and is highly effective in man. By now, the vaccine is available in more than 120 countries.