"Edible vaccines" produced from fruits and vegetables could be protecting people from deadly diseases such as HIV and hepatitis B within the next decade, according to vaccine researcher Dr Alexander V. Karasev, from the Pennsylvania-based Thomas Jefferson University.

Speaking yesterday [Thursday] at an American Medical Association briefing on food biotechnology, Karasey explained that plants such as potatoes, soybeans and tomatoes can be genetically altered to produce antibodies against deadly diseases.

"So far, we haven't seen the technology progress to the commercial stage - it's still relatively young - but probably within the next 5 years we can expect some products to reach the market."

And when they do reach the market, they could ultimately prove cheaper and safer than conventional vaccines because they will not require any special storage or medical equipment, said Karasey, which will make them more widely available in developing countries.

Karasev is currently working with a team of researchers on developing an inoculation against hepatitis B, a disease that can lead to liver cancer, to be delivered via a lettuce. The conventional vaccine costs around US$450 per person. So far, a group of volunteers in Poland produced antibodies against the virus when they ate the transgenic lettuce.

Karasev added however that questions still hang over the potential side effects of such technology and the proper dosages.