Some parents are choosing not to vaccinate their children, leading to the revival of diseases that are avoidable thanks to vaccines.
Now, following the worst measles outbreak in decades, a new law in the state of New York has come into effect to prohibit unvaccinated children from going to school.
The law has been met with outrage by anti-vax parents, who have taken to social media to react.
Enacted in June, the mandate, "prohibits a school from permitting any child to be admitted to such school, or to attend such school, in excess of 14 days without sufficient evidence that the child has received all age-appropriate required vaccinations," an official publication from the New York Department of Health, Office of Children and Family Services, and the State Education Department revealed.
Under the ruling, parents of unvaccinated children will have 14 days to remove them from their schools or have them vaccinated.
State officials told Buzzfeed News that 26,217 unvaccinated New York children in public schools, private schools, parochial schools, daycare centers, and prekindergarten programs claimed religious exemptions which are no longer valid for the 2017-18 school year.
Many anti-vax parents are motivated by unfounded claims that vaccinations cause conditions like autism, despite there being no scientific backing.
In a statement to BuzzFeed News, the New York Health Department said, "Immunizations give children the best protection from serious childhood diseases and the science is crystal clear that vaccines are safe and effective."
Paris Pappas, 43, told Newsday that the ban has created "absolute hell" for anti-vax parents.
"We're just watching everybody else's school life go on, and my life has stopped, basically," she said, before revealing that she now plans to homeschool her three children instead of having them vaccinated.
This news comes in the wake of Germany announcing that measles vaccinations are now compulsory for all children.