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 vaccination 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 Eradication 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 paralysis, 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.