New Delhi, Jan 7 (IANS) The bivalent polio vaccine campaign was Sunday launched in two states - Delhi and Uttar Pradesh. Children below five years of age were administered the vaccine, capable of simultaneously controlling two strains, P1 and P3, of the polio virus.

The central government has procured 42 million bivalent polio vaccines under the new immunisation campaign, a senior health ministry official told IANS.

The bivalent polio vaccine was launched in India Jan 9 under the new round of the national polio immunisation campaign. Bihar was the first state to administer the vaccine.

Delhi last year reported four polio cases - three P1 and one P3.

C.M. Kaneju, officer on special duty with the pulse polio programme in Delhi, said: 'We have begun administering bivalent oral polio vaccine (BoPV) to children below five years of age. There are some 8,200 centres where the vaccines are being given. From tomorrow (Monday), for a few days we will also do door-to-door canvassing to administer doses to those who have missed the camps.'

Delhi has a large migrant population which poses a threat of the virus being transmitted from neighbouring districts of Uttar Pradesh, which reported 571 cases - the highest among other states last year, Kaneju said.

He added that the polio immunisation drive in Delhi this time is targeting over 2.5 million children.

Coinciding with the launch of the vaccine, Rotary International also bestowed the Polio Eradication Champion Award to Union Health Minister Ghulam Nabi Azad, the health ministry official said.

Earlier, separate rounds of the immunisation vaccines were being administered to tackle the P1 and P3 strains. While P1 is the wild strain, P3 is the less virulent form. Both strains are active in India, primarily in Uttar Pradesh and Bihar.

In 2009, at least 721 cases of polio were reported, of which 641 were P1 and 79 P3 cases. One case was a mix of both viruses. Bihar, where 114 cases were reported last year started administering the BoPV in January this year.

There are three strains of polio virus - P1, P2 and P3. The P2 wild polio virus was eliminated in 1999. Efforts are being made to eradicate P1 and P3 also.

The pulse polio programme was started in India in 1995 with the objective of eradicating polio. Before the campaign, the number of paralytic cases due to polio was about 50,000 every year.