VOA标准英语2012--Study Shows PFCs Can Reduce Vaccine Effectiveness

Study Shows PFCs Can Reduce Vaccine¹ Effectiveness

When children are vaccinated² their immune systems produce antibodies that protect them from debilitating³ and potentially deadly childhood infections, such as polio, measles⁴, diphtheria and tetanus. The protection is supposed to last a lifetime.
But scientists say the effectiveness of these vaccines⁵ is severely⁶ reduced when children are exposed to high levels of PFCs:
“This was quite serious because we could also see some of the children were so low in antibody concentration that they were essentially⁷ not protected. They have been vaccinated four times and vaccines had not worked,” said Dr. Phillipe Grandjean of the Harvard School of Public Health.
Grandjean led a team of scientists in a study of children living on the Faroe Islands between Scotland and Iceland.
The islanders were chosen as subjects because their diet is mainly seafood⁸, known to have high concentrations of PFCs.
The scientists followed a group of more than 500 children who'd been vaccinated against diphtheria and tetanus. But children who showed elevated levels of PFCs in their blood also had very low concentrations of antibodies against these infections.
“It was quite a striking fact, one that I would not have anticipated,” said Dr. Peter Hotez, president of the Sabin Vaccine Institute, which promotes vaccine development and delivery around the world.
Hotez said if PFCs do, in fact, interfere⁹ with antibodies and immune system functions, then the public health problem is going to be much worse in the urban slums of low- and middle-income countries, where exposure to these industrial chemicals can be much higher.
“Even a modest reduction in vaccine coverage¹⁰ and vaccine immune responses could lead to subsequent outbreaks of childhood disease. And there is a risk that we could see recurrences¹¹ of childhood killers¹² such as diphtheria or pertussis or other childhood diseases now becoming more common in the world’s poorest countries,” said Hotez.
Scientists say PFCs are stable and persistent¹³ chemicals that have been in wide use for decades - so much so that everyone probably has detectable¹⁴ levels of the compounds in their body.
“We have not done enough in regard to protecting the population against these old compounds, and now we are stuck because we all have them in our bodies and we are all using them,” said Grandjean.
Critics note that since the study was done on island residents eating a mostly fish diet, it should have taken into account polyunsaturated fatty acids [PUFAs], which are found in fish and may suppress the immune system.
Researchers say there is an urgent need to study the adverse¹⁵ health effects of perfluorinated compounds on larger populations.

1 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

2 vaccinated   

[医]已接种的，种痘的，接种过疫菌的

参考例句：

• I was vaccinated against tetanus. 我接种了破伤风疫苗。
• Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗？

3 debilitating   

a.使衰弱的

参考例句：

• The debilitating disease made him too weak to work. 这个令他衰弱的病，使他弱到没有办法工作。
• You may soon leave one debilitating condition or relationship forever. 你即将永远地和这段霉运说拜拜了。

4 measles   

n.麻疹，风疹，包虫病，痧子

参考例句：

• The doctor is quite definite about Tom having measles.医生十分肯定汤姆得了麻疹。
• The doctor told her to watch out for symptoms of measles.医生叫她注意麻疹出现的症状。

5 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

6 severely   

adv.严格地；严厉地；非常恶劣地

参考例句：

• He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
• He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

7 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

8 seafood   

n.海产食品，海味，海鲜

参考例句：

• There's an excellent seafood restaurant near here.离这儿不远有家非常不错的海鲜馆。
• Shrimps are a popular type of seafood.小虾是比较普遍的一种海味。

9 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

10 coverage   

n.报导，保险范围，保险额，范围，覆盖

参考例句：

• There's little coverage of foreign news in the newspaper.报纸上几乎没有国外新闻报道。
• This is an insurance policy with extensive coverage.这是一项承保范围广泛的保险。

11 recurrences   

n.复发，反复，重现( recurrence的名词复数 )

参考例句：

• It was a melancholy tempered by recurrences of faith and resignation and simple joy. 心中不时产生信念，乐天知命的情绪，单纯的欣悦，从而冲淡了忧郁的气质。 来自辞典例句
• The interval without tumor burden turned shorter after multiple recurrences. 多次复发者复发间期逐渐缩短。 来自互联网

12 killers   

凶手( killer的名词复数 )； 消灭…者； 致命物； 极难的事

参考例句：

• He remained steadfast in his determination to bring the killers to justice. 他要将杀人凶手绳之以法的决心一直没有动摇。
• They were professional killers who did in John. 杀死约翰的这些人是职业杀手。

13 persistent   

adj.坚持不懈的，执意的；持续的

参考例句：

• Albert had a persistent headache that lasted for three days.艾伯特连续头痛了三天。
• She felt embarrassed by his persistent attentions.他不时地向她大献殷勤，使她很难为情。

14 detectable   

adj.可发觉的；可查明的

参考例句：

• The noise is barely detectable by the human ear.人的耳朵几乎是察觉不到这种噪音的。
• The inflection point at this PH is barely detectable.在此PH值下，拐点不易发现。

15 adverse   

adj.不利的；有害的；敌对的，不友好的

参考例句：

• He is adverse to going abroad.他反对出国。
• The improper use of medicine could lead to severe adverse reactions.用药不当会产生严重的不良反应。