【英语语言学习】疫苗可以用来诊治毒品上瘾？

Scientists have developed an experimental vaccine 1 to treat individuals addicted 3 to the drug heroin 4. Such a treatment would be a major step forward for both public health and safety.
 
As we hear from Avi Arditti, heroin dependency not only destroys human lives, but fuels a violent drug trade.
 
An estimated 20 million people around the world are addicted to heroin and other opiate drugs -- all products of the opium 5 poppy plant. Their drug dependency and use of unclean needles puts heroin users at risk of a number of diseases.
Recovering heroin addicts 6 use art therapy and other methods to rebuild their lives at a sober house in Zanzibar, February 9, 2012.
It is difficult to keep heroin addicts away from the drug even after they have received treatment to help them end their dependency. But the experimental vaccine may prevent addiction 7 even if a user is offered the drug after leaving a treatment center.
 
The vaccine is the work of Kim Janda and his team at the Scripps Research Institute in La Jolla, California. It tricks the body’s natural defenses for fighting disease into thinking heroin is harmful, like a bacterium 8 or virus. The vaccine causes the immune system to produce antibodies that keep heroin from reaching the brain.
 
“So, it just, it creates like a wall to block the drug from entering the brain, the pleasure centers.”
 
Professor Janda is both a chemist and an immunologist. He says developing a vaccine against heroin has been difficult because the body can quickly change the drug into several byproducts. These include morphine -- the drug that produces the feeling that heroin users desire. 
 
Researchers had to develop a vaccine that would help the body’s immune system recognize and fight those chemicals before they reach the brain. To do that, they experimented on heroin-addicted rats. These animals also had an unlimited 9 supply of the drug.
 
Dr. Janda says the rats were kept away from heroin for one month. That is about the amount of time required for a human addict 2 to complete a drug treatment program.
 
Then, researchers put the rats into two groups, giving both groups as much water filled with heroin as they wanted. But half the rats had been given the experimental vaccine. Researchers found that the vaccine had a clear and measureable effect on those animals.
 
“What happens if you don’t vaccinate 10 them they re-escalate and, and double the amount of intake 11. In, in the case of the ((rats given the)) vaccine, they completely don’t recognize the heroin at all and stop taking it.”
 
None of the vaccinated 12 rats became addicted to heroin, even after being re-exposed to the drug.
 
The National Institute on Drug Abuse helped to pay for the research. David Shurtleff is the acting 13 deputy director of the agency. He warns that a heroin vaccine is not a complete cure. He says it would have to be used as part of a treatment program that also helps drug addicts change their behavior.
 
Researchers at the Scripps Institute are now looking for financing to pay for tests of the vaccine on humans, possibly by later this year.
 
I’m Avi Arditti.
 
From “King Heroin,” by James Brown:
All through your sentence you’ve become resolved to your fate 
Hear now, young man and woman 
I’ll be waitin’ at the gate 
And don’t be afraid, don’t run, I’m not chased
Sure my name is Heroin, and you’ll be back for a taste
 
James Brown:
Behold, you’re hooked, your foot is in the stirrup 
And make haste, mount the steed and ride him well 
For the white horse of heroin will ride you to Hell, to Hell 
Will ride you to Hell…