A new vaccine against polio, being used for the first time on children in Afghanistan, will be critical in the drive to eradicate the paralysing virus, says the World Health Organisation.
The bivalent oral polio vaccine (bOPV) is made by GlaxoSmithKline, the first of five manufacturers to be licensed.
Some 2.8 million children under the age of five are being inoculated in the southern, south-eastern and eastern regions of Afghanistan this month in a campaign financed by the Canadian government.
The new vaccine is effective against type 1 and type 3 of the virus and the WHO said the vaccination programme would "vastly simplify the logistics of vaccination in the conflict-affected parts of this country".
Most of Afghanistan is polio-free: 28 out of the 31 children paralysed by polio this year come from 13 highly insecure districts (of 329 districts in the country). However, the proportion of children who are still unimmunised in Kandahar and Helmand in the southern region is well above 20% - and more than 60% in some areas.
Four countries - Afghanistan, India, Nigeria and Pakistan - have been unable to stop the spread of polio, which attacks the nervous system and can cause irreversible paralysis. Types 1 and 3 polio circulate in limited parts of all these countries, and they will follow Afghanistan's lead in using bOPV during the coming months in the international effort to eradicate polio.
While the Global Polio Eradication Initiative, spearheaded by the World Health Organisation, Rotary International, the US Centres for Disease Control and Prevention and UNICEF, has reduced the incidence of polio by more than 99% (from an estimated 1,000 children affected daily in 1988 to 1,483 children in the whole of 2009 to date) polio still has a foothold in the four endemic countries.
The availability of bOPV is part of a range of new and area-specific tactics in 2009 to reach eradication more quickly.