Yet, while in theory, doctors should find another physician who will treat an unvaccinated child, in the real world, it can put families in a difficult spot.
After Echan left her first pediatrician, she said she could not find another doctor who would take her family, once she told them she was unwilling to vaccinate her children.
"I don't know what happened to my older one, I just know that he has autism and he wasn't born with it," said Echan. "So I don't know what to do then, I'm scared."
Dr. Steven Abelowitz, director of the Coastal Kids clinic where Echan was first turned away, says the process of dealing with parents who don't want to be vaccinated is evolving.
Abelowitz didn't see Echan, nor could he speak to what happened that day. However, he said he does try to work with families who fear there's a link between vaccines and autism.
"Four or five years ago, it really was a rare instance that someone wouldn't want to do vaccines," said Abelowitz, who is an adjunct professor at the University of California Los Angeles and University of Southern California.
"Now we deal with vaccine concerns 10-20 times a day," he said.
Abelowitz says his office tries to provide as much information as possible on the risks and benefits of vaccines, and Coastal Kids even works with families to spread out the vaccination schedule over a longer period of time.
"The big, big change came after Jenny McCarthy came on TV," said Abelowitz. "Knowing now how many people fear it, we really want to try to work with parents."
However, Abelowitz said he does have concerns about keeping unvaccinated children in a practice, especially if the children aren't vaccinated against whooping cough, or pertussis, which can be fatal in young children and is still found in the United States.
Abelowitz also says he worries about babies coming into his office having contact with older children whose parents have refused to allow vaccinations.
"We also have to be responsible to the kids in the waiting room ... my biggest fear is [for] these young babies who are under the age of 2 months who are not vaccinated."
In the end, Echan took her children to see a naturopath -- a person who studied holistic medicine but does not have a legal license to practice medicine in most states.
"I love doctors; I'm not opposed to doctors. I just haven't needed them yet," said Echan. "I know that there are pediatricians out there who will take children who aren't vaccinated."