An injection of genes that make antibodies against nicotine could help millions of smokers kick the habit, scientists believe.
Just one jab could provide life-long protection against nicotine cravings and it could eventually be used to vaccinate children to stop them ever getting hooked.
The ‘genetic vaccine’ has so far been tested only on mice, but research involving people could begin in as little as two years.
The jab contains genes ‘programmed’ to make antibodies that neutralise nicotine before it reaches the brain, where it would normally trigger the pleasurable feelings that underlie addiction.
The theory is that if smokers no longer get such gratification from cigarettes, they will find it easier to quit.
The jab being developed at Weill Cornell Medical College in New York tricks the liver into continuously making antibodies, ensuring there are always some in the blood to fight nicotine.
When vaccinated mice were given nicotine, the antibodies cut the amount that made its way to the brain by 85 per cent, with no effect on their behaviour, blood pressure or heart rate, reports the journal Science Translational Medicine.
Most smokers who try to quit light up again within six months, but lead researcher Dr Ronald Crystal said: ‘This novel vaccine may offer a much-needed solution.’
The research is still at an early stage and the need for large-scale studies means the jab is at least five years from the market.
If it proved to be safe and effective, it could eventually be included in school vaccination programmes to stop youngsters from ever starting to smoke, said Dr Crystal.
Darren Griffin, professor of genetics at Kent University, said the study had ‘great potential’, but warned that what worked in mice did not always work in man.
Prof Anthony Dayan, a retired toxicologist, said: ‘Nicotine addiction via smoking is harmful, but is it ethical to produce a major and enduring change in someone’s body to prevent it when other, less major, types of treatment are feasible?’
Around a fifth of Britons smoke, with most starting while still in their teens. Previous studies have shown that existing treatments, from counselling to pills, are of little benefit, with up to 80 per cent smoking again within six months.