The Nic Fix | Science | Smithsonian

The Nic Fix

Put down your lighters and pick up your health care cards—, nicotine vaccines are in the works

smithsonian.com

I smoked cigarettes for five years (sorry, Mom) before quitting cold turkey. A lot of my smoking buddies, however, have had more of a struggle. One friend cut back by chomping nicotine gum; he uses the words "cardboard" and "perspiration" when describing its taste. Another quit after reading a simple-steps-to-stopping book, and now reacts harshly to any implication that he's been brainwashed. One girl, determined to hide her habit from co-workers but unwilling to resist a lunchtime puff, lugged a bottle of fabric refresher in her gigantic purse.

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Wouldn't it be easier if we could vaccinate cigarette addiction—give people a shot that would either make it tougher for them to get into the habit, or help them kick it once they've started? When can we put down our Febreze, bare our biceps and tell the nurse to be quick?

Within a decade, and perhaps in just a few years. But even then this smoking vaccine won't be a one-and-done affair, or a lifelong cure.

Nicotine molecules are too small to trigger the body's immune system. They pass through the lungs into the brain and deliver pleasurable chemicals, like dopamine, in high enough volumes to make us forget the five bucks we just spent on a pack.

For a smoking vaccine to be effective, scientists must first trick the immune system into recognizing nicotine as a foreign invader. They do this by attaching nicotine molecules to protein carriers; this new concoction is large enough to launch the body's defenses.

As the vaccine is cleared from a person's system over the next several weeks, immune cells prepare antibodies that circulate in the bloodstream, awaiting another nicotine attack. When that next puff does come, these antibodies intercept the nicotine molecules before they cross into the brain.

In light smokers, the antibodies can stop some nicotine molecules from reaching the brain. In heavier smokers these defenders slow down nicotine delivery, blunting the swift, powerful reward that typically comes from a fresh smoke. Ultimately the habit becomes less reinforcing.

This lack of reinforcement might be particularly effective against relapse. Smokers who have kicked the habit for a while but find themselves in need of nicotine—perhaps they're at a party, or under stress from an approaching column deadline—could fail to find the relief they require. (And, in case they turn to stronger fixes, cocaine vaccines are also in the works.)

The vaccine also prolongs the amount of time nicotine spends in the body, known as clearance. That might seem like a bad thing, but people with naturally longer clearance times actually smoke fewer cigarettes.

Don't light up a victory stick just yet. Antibodies produced by the nicotine vaccine fade over several months, like so much smoke in the wind. Right now the vaccine—still undergoing clinical trials—requires four to five injections, each a month or so apart. Follow-up booster shots would be necessary for lifelong protection.

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