AN obesity vaccine has been developed that uses the immune system to keep the body slim. The "flab jab" has shown promising early results in mouse studies.
If the vaccine passes further safety trials, scientists believe it could provide a revolutionary new weapon against obesity.
Currently the only non-dieting options for controlling weight are surgery and strong drugs that can have serious side effects.
The vaccine works by stimulating the immune system to attack a hormone that promotes slow metabolism and weight gain.
In tests, obese mice fed a high fat diet saw a 10pc drop in body weight four days after receiving the jab. Two slightly different versions of the vaccine were studied. Both produced a sustained 10pc reduction in body weight after booster injections were administered after three weeks.
The slimming effect was not seen in a matched group of 10 untreated mice. Lead researcher Dr Keith Haffer, from the US company Braasch Biotech in South Dakota, said: "This study demonstrates the possibility of treating obesity with vaccination. Although further studies are necessary to discover the long- term implications of these vaccines, treatment of human obesity with vaccination could provide physicians with a drug and surgical-free option against the weight epidemic."
Being obese is defined as having a Body Mass Index (BMI) -- a measurement relating height and weight -- of 30 or more.
The new vaccine uses a modified form of somatostatin, a peptide protein molecule that functions as a hormone.
In both mice and humans somatostatin suppresses growth hormones that boost metabolism and cause weight loss.
The vaccine "flags up" somatostatin so that it is seen as a potential threat by the immune system. It causes the body to generate antibodies that neutralise the peptide.
In the Journal of Animal Science and Biotechnology, the scientists wrote: "The vaccination effects did not significantly reduce cumulative food consumption and was confirmed by residual anti-somatostatin antibodies in mouse plasma at the study's end."