SHOULD every teenager be given a vaccine that blocks the effects of nicotine and so prevents them becoming addicted to the evil weed?
This controversial possibility is on the horizon thanks to the development of two pioneering vaccines for nicotine addiction. The vaccines were designed for people who repeatedly relapse after giving up smoking. But since most countries are failing to cut the number of children and teenagers taking up cigarettes, many will ask if the vaccines should be used far more widely if they prove to be effective.
One, developed by Florida company Nabi Biopharmaceuticals, began safety trials this week on 20 non-smokers. The other vaccine, made by British drugs company Xenova, has just successfully completed the first stage of testing on 50 smokers and 10 non-smokers. 鈥淲e鈥檙e very pleased with our results,鈥� says John Roberts, Xenova鈥檚 medical director.
Advertisement
Both vaccines work by stimulating the immune system to make antibodies against nicotine. Once an antibody binds to nicotine, the resulting complex is too big to get into the brain, and so can鈥檛 activate the 鈥減leasure鈥� receptors that generate the drug鈥檚 addictive buzz.
The body doesn鈥檛 naturally make antibodies to nicotine because the molecule is too small. But if you attach nicotine to a large protein, as both companies have, the immune system can see it and churn out antibodies that target nicotine alone. The idea is to get the body to make enough antibodies to mop up any nicotine before it reaches the brain, although animal studies suggest that the way such vaccines work is rather more complicated (see New 杏吧原创, 10 June 2000, p 22).
The vaccines will be tested first on relapsing smokers, then those who want to quit, then those who鈥檙e not yet completely hooked, says Frank Vocci of the National Institute on Drug Abuse near Washington DC, which co-sponsored the Nabi vaccine. The final leap would be vaccinating youngsters before they even try smoking, but Vocci says that鈥檚 a long way down the road.
Roberts of Xenova is more gung-ho. 鈥淚 think [prevention] offers a huge opportunity,鈥� he says. 鈥淚f you can take away the pleasure from the outset, children are more likely to kick the experiment early. It normally takes several cigarettes to build up addiction.鈥�
Eighty per cent of smokers start in their teens, with 360,000 teenagers and children in the US alone taking up the habit last year. 鈥淏ut there are civil liberties issues. Who will decide which individuals are most at risk of becoming smokers and suggest they take the vaccine?鈥� says Amanda Sandford of Action on Smoking and Health (ASH), a London-based anti-smoking charity. Instead, she favours education as a way of discouraging youngsters from smoking.
Mark Soufliers of Nabi is also cautious. 鈥淭he challenge is at what age you鈥檇 give the vaccine, and whether you鈥檇 need to give regular boosters,鈥� he says. If antibody levels dropped too low, kids might try cigarettes thinking they鈥檇 be immune to nicotine only to become hooked. 鈥淎lso, how much right does the child have to say no?鈥�
There are also worries about giving the vaccine to smokers. Since it doesn鈥檛 get rid of the cravings, will smokers simply try to beat the antibodies by smoking much more than usual? Gary Horwith, Nabi鈥檚 clinical director, says this would be virtually impossible. 鈥淚f antibody production is comparable in people to that we saw in animals, you鈥檇 have to stick an entire pack of cigarettes in your mouth at once and smoke for hours to override the antibodies,鈥� he says.