VOA慢速英语2010年-Development Report - New Vaccine Joins

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This is the VOA Special English Development Report.

An Afghan girl receives a dose of polio vaccine¹

The World Health Organization has begun to use a new vaccine against polio. Officials say it will become a major tool in the campaign to end a disease that mainly affects children under age five.

The new formulation is known as B.O.P.V. , or bivalent oral polio vaccine. It was used for the first time in December in a polio immunization campaign in Afghanistan.

Carol Pandak is with the PolioPlus program of the service organization Rotary² International. She explains that health workers have been using what are called trivalent vaccines³ in some places. These are areas like Afghanistan where more than one kind of polio virus exists.

There are three types of polio virus. The trivalent vaccine is least effective against type three, more effective against type one and highly effective against type two. As a result, few new cases of type two have been reported since nineteen ninety-nine.

This has led to greater use of monovalent vaccines to protect against either type one or type three polio. But Carol Pandak says the monovalent vaccine is not enough in areas with both.

CAROL PANDAK: "You address the type one, and the type three cases go up. You address the type three, and the type one cases go up."

Rod Curtis at the World Health Organization in Geneva says the new bivalent vaccine solves this problem.

ROD CURTIS: "The beauty of the bivalent vaccine is that it is able to attack both types of wild polio virus in one dose."

Carol Pandak says tests found the new vaccine to be thirty percent more effective than the trivalent vaccine.

More than thirty new cases of polio were reported in Afghanistan last year. About half were type one and the others type three. Rod Curtis says that shows the importance of the new vaccine targeting both viruses at once. Officials say similar vaccination⁴ campaigns are planned this year in India, Nigeria and Pakistan.

Intensive vaccination campaigns have reduced the number of new polio cases reported worldwide to fewer than two thousand a year. The Global Polio Eradication⁵ Initiative says the number has fallen by ninety-nine percent since nineteen eighty eight.

Polio is highly infectious. One victim in two hundred suffers permanent paralysis⁶, usually in the legs. Five to ten percent of those victims die when their breathing muscles fail.

And that's the VOA Special English Development Report, written by June Simms. I'm Steve Ember.