"There is no need to allow the state to strip parents of their rights to make medical decisions for their own kids," the group's website reads. "Given that vaccines have known risks associated with them, it seems only prudent to continue the philosophical exemption, and to make sure that we are not divided by fear mongering."
Calls to the Vermont Coalition for Vaccine choice were not immediately returned.
Schaffner said it's impossible to know who would have natural immunity, adding that herd immunity works only if the majority of the population is vaccinated, which stresses the importance of getting vaccinated.
"Parents who withhold their own children from immunization are taking advantage of all those who do get their children immunized," he said.
In addition, he said, some children have medical conditions that preclude them from receiving vaccinations.
"The way we protect them is for all the rest of us to be protected," Schaffner said.
Given the current resistance to Vermont's bill, passage is expected to be a hard fought battle.
The bill is now being discussed in a conference committee, which consists of three house and three senate members, to negotiate the terms of the bill. The committee has already met three times and is scheduled to decide by the first week of May.
"The realistic expectation is that a compromise will be struck and that will make philosophical exemptions harder to attain," he said.
Amy Pisani, executive director of Every Child by Two, an organization that advocates for vaccinations, said such a compromise should require that parents receive education on the importance of vaccines.
"The question at hand is whether individuals have the right to shirk the laws put in place to maintain the health of some of Vermont's most vulnerable citizens; infants and school children," she said.