An injection that practically eliminates alcohol cravings could help reduce the 2.5 million booze-related deaths each year.

"The vaccine delivers an instant hangover of epic proportions," said Dr Juan Asenjo at the University of Chile in Santiago, where the jab is being developed.

"If a patient takes one sip of alcohol after the injection, those typical hangover symptoms, such as rapid pulse rate, sweating and nausea, are magnified to the point where the mere idea of another drink is repellent."

In early trials, it has reduced alcohol intake by more than 90 percent in subjects - and completely in a number of cases.

The shot, which cannot be reversed, is likely to remain effective for about six months and works by speeding up the hangover process. It sends a biochemical message to the liver to prevent it from processing alcohol.

When a person who has had the vaccine tries to drink alcohol, they will immediately feel severe nausea.

The purpose of the jab is to get alcoholics to associate drinking with deeply unpleasant sensations such as a splitting headache.

Preclinical trials on mice to establish the correct dosage begin next month.

Researchers hope to begin human trials in November.

Dr Asenjo, director of the Institute for Cell Dynamics and Biotechnology at the Universidad de Chile, said the vaccine is not a cure-all, but could provide an important first step.

"People who end up alcoholic have a social problem; a personality problem because they're shy, whatever, and then they are depressed, so it's not so simple," he told the Santiago Times.

"But if we can solve the chemical, the basic part of the problem, I think it could help quite a bit.

"If it works, it's going to have a worldwide impact, but with many vaccines one has to test them carefully. I think the chances that this one will work are quite high."

The idea for the vaccine came from the Far East, said Dr Asenjo, where up to 20 percent of Japanese, Chinese or Koreans have a mutation which inhibits the breakdown of alcohol in their bodies.

The research findings are encouraging but many medical organisations feel the medications still fall short of being a complete cure. Put simply, there is no alcoholism pill - apart from quitting drinking completely.

Drugs to combat alcoholism

    • A new study by Lianne Schmaal at the University of Amsterdam suggests that Modafinil (Provigil), a drug originally developed to increase wakefulness, may help some people to reduce drinking by improving their impulse control.
    • Disulfiram, a drug marketed as Antabuse, blocks the enzyme that breaks down alcohol, causing nausea if the patient drinks alcohol. However, users often find the effects so unpleasant they simply stop taking the pills. Also, many in the medical establishment reject Antabuse because a doctor's oath is to "first do no harm".
    • Acamprosate is a drug that claims to help manage emotional triggers in people who have already stopped drinking.
    • Naltrexone helps manage cravings in heavy drinkers who are trying to stop drinking or have recently quit.