STOCKHOLM ? An anti-nicotine vaccine will be tested on 400 people in the Nordic countries over the next year aimed at helping smokers kick the habit, the Karolinska Institute in Sweden said on Monday.

"A Swedish vaccine against nicotine will be tested on 400 people in three Nordic countries," the institute said in a statement.

Lena Wikingsson, head of Independent Pharmaceutica, which is running the experiment, told Swedish daily Svenska Dagbladet that people taking part in the study -- heavy smokers who would like to quit -- would be given counseling before they stop smoking and would be given a drug to help them quit.

They will then receive one injection a month for four months. Half of the participants will be given the vaccine and the other half a placebo.

They will be followed for a year to see whether they begin to smoke again, Wikingsson said.

The vaccine, called Niccine, has been developed over the course of 10 years by Swedish researchers at the Karolinska Institute, under the guidance of professor Torgny Svensson who founded Independent Pharmaceutica.

Niccine is supposed to help the immune system build antibodies against nicotine.

If a person who has taken the vaccine smokes a cigarette, the antibodies jump into action, latching onto the incoming nicotine and preventing it from reaching the reward system in the brain -- thereby stopping the smoker from getting the "kick" that makes smoking addictive.

One problem in developing nicotine vaccines is that the immune system doesn't react to normal nicotine.

In order to activate the immune system, the nicotine in the vaccine needs to be latched onto a "carrier" or "host" that stimulates the immune system to create as many antibodies as possible.

For the vaccine to be successful, a large number of antibodies must be created, and the carrier component is therefore the key part of Niccine, Wikingsson said.

"There are several possible applications if the vaccine proves to be effective," Wikingsson told Svenska Dagbladet.