脊髓灰质炎新疫苗跨积极一步

 UNITED NATIONS, April 15 (Xinhua) -- A new polio vaccine¹ will be rolled out next week to replace the one which protects against all three strains of wild poliovirus.

It marked the beginning of the largest and fastest globally coordinated² rollout of a vaccine into routine immunization programs in history, said Farhan Haq, the deputy UN spokesman, at a daily news briefing held here Friday.

Between April 17 and May 1, 155 countries and territories in the world will stop using the trivalent oral polio vaccine (tOPV), which protects against all three strains of wild poliovirus, and replace it with bivalent OPV (bOPV), which protects against the remaining two wild polio strains, types 1 and 3, Haq said.

"This transition, referred to as the global vaccine 'switch,' is possible because type 2 wild polio has been eradicated," he said.

The switch is a significant milestone³ in the effort to achieve a polio-free world. In 2015, there were fewer cases reported in fewer countries than before.

This year, the focus is on reaching every child with the polio vaccine and stopping the virus in its final strongholds.

The World Health Organization (WHO) and the UN Children's Fund (UNICEF) consider that the world is closer than ever to ending polio worldwide.

The oral polio vaccine (OPV) has been used to stop polio in most of the world. On very rare occasions in under-immunized populations, the live weakened virus contained in OPV can mutate and cause circulating vaccine-derived polioviruses (cVDPV).

More than 90 percent of cVDPV cases in the last 10 years have been caused by the type 2 vaccine strain. Withdrawing tOPV and replacing it in routine immunization programs with bOPV will eliminate the risks associated with the type 2 vaccine strain and, just as importantly, boost protection against the two remaining wild strains of the virus.

The switch must be globally synchronized⁴ because if some countries continue to use tOPV, it could increase the risk of the spread of type 2 poliovirus to those no longer using tOPV. The switch is the first major step toward the eventual⁵ removal of all OPV after wild polio transmission has been stopped.

To ensure that the switch takes place as planned, thousands of independent monitors will confirm the absence of tOPV at public and private service facilities and cold chain stores.

In countries at higher-risk of a polio outbreak, a dose of inactivated⁶ polio vaccine (IPV) has been added to routine immunization schedules, in addition to bOPV, to further boost immunity⁷. To protect against the very small risk of an outbreak of cVDPV type 2 after the switch, a global stockpile of monovalent OPV (mOPV) type 2 is ready to be dispatched if an outbreak occurs.

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 coordinated   

adj.协调的

参考例句：

• The sound has to be coordinated with the picture. 声音必须和画面协调一致。
• The numerous existing statutes are complicated and poorly coordinated. 目前繁多的法令既十分复杂又缺乏快调。 来自英汉非文学 - 环境法 - 环境法

3 milestone   

n.里程碑；划时代的事件

参考例句：

• The film proved to be a milestone in the history of cinema.事实证明这部影片是电影史上的一个里程碑。
• I think this is a very important milestone in the relations between our two countries.我认为这是我们两国关系中一个十分重要的里程碑。

4 synchronized   

同步的

参考例句：

• Do not use the synchronized keyword in Managed Objects. 不要在管理对象上使用synchronized关键字。 来自互联网
• The timing of the gun was precisely synchronized with the turning of the plane's propeller. 风门的调速与飞机螺旋桨的转动精确同步。 来自辞典例句

5 eventual   

adj.最后的，结局的，最终的

参考例句：

• Several schools face eventual closure.几所学校面临最终关闭。
• Both parties expressed optimism about an eventual solution.双方对问题的最终解决都表示乐观。

6 inactivated   

v.使不活泼，阻止活动( inactivate的过去式和过去分词 )

参考例句：

• Molluscicides are quickly inactivated by sunlight and adsorption to mud organic matter. 灭螺剂因阳光作用、泥土及有机物质的吸收会很快失效。 来自辞典例句
• Viruses were inactivated by BPL and the toxicity measured again. BPL对病毒进行灭活，测定残存毒力。 来自互联网

7 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。