During the rubella pandemic of 1964–65, Apgar became an advocate for universal vaccination to prevent mother-to-child transmission of rubella. Rubella can cause serious congenital disorders if a woman becomes infected while pregnant. Between 1964 and 1965, the United States had an estimated 12.5 million rubella cases, which led to 11,000 miscarriages or therapeutic abortions and 20,000 cases of congenital rubella syndrome. These led to 2,100 deaths in infancy, 12,000 cases of deafness, 3,580 cases of blindness due to cataracts and/or microphthalmia and 1,800 cases of intellectual disability. In New York City alone, congenital rubella affected 1% of all babies born at that time.