This has led to greater use of monovalent vaccines to protect against either type one or type three polio.

VOA: special.2010.01.18

The Global Polio Eradication Initiative says the number has fallen by ninety-nine percent since nineteen eighty eight.

VOA: special.2010.01.18

It was used for the first time in December in a polio immunization campaign in Afghanistan.

VOA: special.2010.01.18

These are areas like Afghanistan where more than one kind of polio virus exists.

VOA: special.2010.01.18

Jonas Salk used these HeLa cells to test the first vaccine for polio.

VOA: special.2010.07.21

But a polio outbreak in Washington forced Scout leaders to cancel the event.

VOA: special.2010.08.06

Bobbi Wailes developed polio before a vaccine became available in the nineteen fifties.

VOA: special.2010.07.28

The World Health Organization has begun to use a new vaccine against polio.

VOA: special.2010.01.18

More than thirty new cases of polio were reported in Afghanistan last year.

VOA: special.2010.01.18

The new formulation is known as B.O.P.V., or bivalent oral polio vaccine.

VOA: special.2010.01.18

Last year, we launched an aggressive new strategy for polio eradication.

VOA: special.2011.01.19

and to help contain an outbreak of polio.

VOA: special.2010.05.03

There are three types of polio virus.

VOA: special.2010.01.18

Polio is highly infectious.

VOA: special.2010.01.18