(Reuters) - A new double-strain polio vaccine is more effective than triple and single vaccines and means children in high-risk areas can be immunized against two key strains of the crippling virus in a single dose, scientists say.
(Reuters) - A new double-strain polio vaccine is more effective than triple and single vaccines and means children in high-risk areas can be immunized against two key strains of the crippling virus in a single dose, scientists say.