A day after a report in The Daily Beast characterized Biel as "coming out as an anti-vaxx activist," the actress declared on Instagram Thursday that she "is not against vaccinations."
"I support children getting vaccinations and I also support families having the right to make educated medical decisions for their children alongside their physicians,'' she wrote.
The Daily Beast reported that "The Sinner" star appeared at the California State Assembly in Sacramento on Tuesday with anti-vaccine advocate Robert F. Kennedy Jr. to lobby against a California state bill that would limit medical exemptions from vaccinations without approval from a state public health officer.
Biel clarified that her concern with the bill, SB 276, was "solely regarding medical exemptions."
"My dearest friends have a child with a medical condition that warrants an exemption from vaccinations, and should this bill pass, it would greatly affect their family's ability to care for their child in this state,'' she wrote. "That's why I spoke to legislators and argued against this bill. Not because I don't believe in vaccinations, but because I believe in giving doctors and the families they treat the ability to decide what's best for their patients and the ability to provide that treatment."
Biel had never publicly commented on the controversial issue before her Instagram post Thursday. Her representatives have not commented on The Daily Beast story or other reports.
The issue of children being vaccinated has continued to be a hot-button topic, with medical experts noting that scientific studies show that vaccines being linked to autism is a myth.
There were 1,022 cases of measles reported across the country from January through June 6, the greatest number since 1992 and since measles was declared eliminated in 2000, according to the Centers for Disease Control.
The CDC attributed the jump in cases to travelers getting measles abroad and bringing it home to the U.S., causing a spread in communities with pockets of unvaccinated people.