Carter, 84, who co-founded Every Child By Two in 1991, a non-profit that promotes infant vaccinations, said parents need to talk to other moms and dads.
"It would be great if we could get parents all over the country talking to their friends and neighbors, just talking about the situation and how some babies are not being immunized," she told USA Today.
Carter was in Washington recently for Every Child By Two's 20th anniversary as the United States finds itself in the largest measles outbreak in 15 years.
"I know people who don't have their babies immunized think they're doing it for the good of the child," she said. "But the good of the child is to not have these terrible diseases."
More than one in 10 families now selectively delays or skips important shots, a recent study in Pediatrics found.
"Parents need to know these vaccines are safe," Carter said, pointing to more than a dozen studies refuting claims by some that vaccinations cause autism.