The bivalent polio vaccine campaign was on 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, according to a senior Health Ministry official. The bivalent polio vaccine was launched in India on January 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.