LONDON -- The humble potato may help scientists to protect women from a common sexually transmitted virus that causes almost all cases of cervical cancer, IRNA reported.

U.S. researchers hope to engineer a potato that carries a vaccine against the human papilloma virus (HPV).

In theory, this should provide an easy way to spread immunity at the dinner table, reports the BBC News On-Line.

Potatoes produced and tested by scientists at the University of Rochester, Cornell University and Tulane University provoked an immune response in mice that munched on the transgenic spuds.

When enhanced with a substance derived from E.coli to boost their effectiveness, the potatoes provoked the immune system in the same way thought to be necessary to protect humans from the virus.

Researcher Dr. Robert Rose said: "The beauty of an oral vaccine is that you don't need a needle. "In most cases you don't even need a doctor."

Dr. Rose said the potato vaccine could prove to be a highly effective way of protecting women in developing countries - where 80% of deaths from cervical cancer occur.

Currently, there is no HPV vaccine available. The only effective way to limit the spread of the virus is by practicing safe sex.

The U.S. researchers are also examining the possibility of using bananas as a vector for vaccines.

Potentially, they may be a better bet because, unlike potatoes, they are usually eaten raw, so there is no risk that the vaccine will be destroyed by the cooking process.

However, Dr. Rose warned that the use of food-based vaccines would have to be tightly controlled. "Any vaccine has to be prepared and administered in a controlled manner. The crop would be grown, evaluated, processed, and prepared into measured doses."