An unvaccinated Kentucky teenager is suing after his Catholic school excluded him amid a chickenpox outbreak that has sickened at least 32 pupils.
Jerome Kunkel, 18, has not contracted the virus, but he has been banned by Our Lady of the Sacred Heart/Assumption Academy in Walton.
His lawsuit argues the vaccine is "immoral, illegal and sinful" and his rights have been violated.
The Northern Kentucky Health Department banned unvaccinated pupils on 14 March.
The notification said that due to the outbreak of chickenpox, students who have not been vaccinated or are already immune to the infection must stay home "until 21 days after the onset of rash for the last ill student or staff member".
The statement, which also banned all extracurricular activities, said it came "in direct response to a public health threat and was an appropriate and necessary response to prevent further spread of this contagious illness".
Jerome Kunkel's father, Bill Kunkel, said the vaccines were derived from aborted foetuses, which goes against his family's religious beliefs.
"I don't believe in that vaccine at all and they're trying to push it on us," he told WLWT-News.
Some viruses used to make vaccines are grown with cells descended from matter that was sourced from two human foetuses electively aborted in the 1960s.
But no new human cells have been used since then to produce vaccines, according to health authorities and drug manufacturers.
The Catholic Church has told its members it is morally justifiable to use these vaccines, though it wants alternative treatments developed without "using cell lines of illicit origin".
Jerome Kunkel told WLWT-News he is upset about the ban, and especially what it means for his basketball team, which he captains.
"The fact that I can't finish my senior year in basketball, like, our last couple of games, it's pretty devastating," he said.
"I mean, you go through four years of high school playing basketball, you look forward to your senior year."
A court hearing is scheduled for 1 April.
Chickenpox is a highly contagious virus that causes blisters, itching and fever.
Before a vaccine was created, about four millions Americans caught the disease each year, according to the Children's Hospital of Philadelphia.
Now only around 12,000 people catch it each year.