美国FDA：带状疱疹疫苗注射最低年龄，确定为五十岁

March 24, 2011 - People age 50 and older can now get Merck's Zostavax shingles vaccine, the FDA today ruled.
7 U! B' Y$ \/ c/ z' c& B- ]The vaccine already was approved for people age 60 and older. The approval is based on a Merck clinical trial that showed the vaccine to be about 70% effective in preventing shingles in the younger age group.
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The study also found that even when vaccinated 50-somethings did get shingles, they suffered far less pain and far shorter bouts of the painful, sometimes disabling disease.

"The likelihood of shingles increases with age. The availability of Zostavax to a younger age group provides an additional opportunity to prevent this often painful and debilitating disease," Karen Midthun, MD, director of FDA's Center for Biologics Evaluation and Research, says in a news release.

Shingles -- known to doctors as herpes zoster-- is caused by the same herpes virus that causes chickenpox: varicella zoster. But when chickenpox gets better, the virus doesn't go away. It hides in nerve roots. When reactivated in later years, the virus erupts into extremely painful shingles-like lesions.
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Zostavax is basically the same as the chickenpox vaccine, given at a far higher dose. Clinical trials show the vaccine to be both safe and effective.

Why get vaccinated at age 50? That's when shingles risk shoots up. Before age 50, about two people in a thousand get shingles. After age 50, about six people in a thousand get shingles. A person's lifetime risk of shingles is about 30%.

Even people who already have had shingles can get it again. Their risk of a second case is about the same as the risk of getting a first case.

The biggest drawback to Zostavax is its cost. The catalog price is about $161.50, about 10 to 20 times the cost of flu vaccine.
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2011.3.24-FDA今日宣布，50岁以上的成人可使用默克公司的带状疱疹疫苗（Zostavax）。

Zostavax已批准用于60岁以上人士。本批准是基于默克的临床试验。试验表明在较年轻的人群中，该疫苗预防带状疱疹的有效性为70%。

- _4 P  P* J5 A8 d- c- {研究还发现，即使对曾患带状疱疹的50岁以上人士注射疫苗，这些患者发病时疼痛减轻、疼痛带缩短，有时甚至抑制疾病发作。

7 I9 M4 k' F9 `, s! `8 J: I% xFDA生物评估和研究中心的Karen Midthun医生在一次新闻发布会中谈到，“带状疱疹的发病率与年龄增长相关。对较年轻的人士进行带状疱疹疫苗注射有利于预防常见的疼痛并减轻疾病的症状。”
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带状疱疹是由引起水痘相同的病毒感染所致：水痘带状疱疹病毒。但是当水痘好转时，病毒并未消失而隐藏于神经根处。在患者晚年，当病毒再次被活化时，以带样脓肿并伴巨痛的形式爆发。
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Zostavax基本上与水痘疫苗相似，仅其剂量更高。临床实验表明该疫苗兼具安全性和有效性。
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0 u$ d0 H9 ]  O, F; k4 ~为什么在50岁接种疫苗？因该年龄易发带状疱疹。50岁前，仅千分之二的人出现带状疱疹。而50随后，千分之六的人会得带状疱疹。约30%的带状疱疹患者会出现终身危害。即使患者曾得过带状疱疹，亦会再次患病。二次患病的风险率与一次患病相同。

- v% a3 a) Z' Z4 Q/ V! b* |Zostavax最大的缺点就是价格，其价格为161.5美金，是流感疫苗的10到20倍。
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“即使患者曾得过带状疱疹，亦会再次患病。二次患病的风险率与一次患病相同。”
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