Before revision: Resistance proceeded during the mid-1900s and in 1977 a nationwide Childhood Immunization Initiative was developed with the goal of increasing vaccination rates among children to 90%DIF < by 1979.
After revision: ,Resistance proceeded during the mid-1900s and in 1977 a nationwide Childhood Immunization Initiative was developed with the goal of increasing vaccination rates among children to 90%DIF < by 1979.