A new weapon will now lead the country’s fight against polio. On Sunday, the government will launch a first-of-its-kind bivalent oral polio vaccine (BOPV), a single drop to protect against two deadly strains of polio presently existing in the country — P1 and P3. The vaccine currently being used in the country is a monovalent one. It protects against a single strain causing the crippling disease. BOPV will be launched first in Bihar on Sunday followed by Uttar Pradesh, two of the worst affected states with polio.