The court, which has a 6-3 conservative majority, rejected a request made by nine unnamed plaintiffs who identified themselves as healthcare workers who object to receiving the shots on religious grounds.

The court previously rejected challenges to vaccine mandates in New York and Indiana, though those cases did not involve religious objections.

The justices were divided, with three conservative members saying they would have granted the request. In Maine, “healthcare workers who have served on the front line of a pandemic for the last 18 months are now being fired and their practices shuttered,” conservative Justice Neil Gorsuch wrote in a dissenting opinion.

He was joined by Justice Clarence Thomas and Justice Samuel Alito. Maine Governor Janet Mills’ administration had required that all healthcare workers in the state be fully vaccinated by the beginning of October, but the state said it would not enforce it until Friday.

The governor said such workers perform a critical role in protecting the health of Maine’s residents and that every precaution needed to be taken to protect against the spread of the coronavirus, especially in light of the presence of the highly transmissible Delta variant.Maine removed religious exemptions from mandated vaccines in 2019 – before the pandemic – because of falling vaccination rates. Voters in the state overwhelmingly rejected a referendum challenging the law last year.

The state has required hospitals and other healthcare facilities to ensure that workers are vaccinated against various diseases since 1989.

The challengers argued that the lack of a religious exemption violated their right to free exercise of religion under the US Constitution’s First Amendment. A federal judge had earlier rejected the bid for an exemption.

The conservative-majority Supreme Court, which has been receptive to claims involving religious rights, rejected two previous challenges to Covid-19 vaccine mandates. Justice Sonia Sotomayor in October refused to block New York City’s requirement that public school teachers and employees be vaccinated. Justice Amy Coney Barrett in August denied a bid by Indiana University students to block that school’s vaccination mandate.

Also on Friday, a federal appeals court in New York ruled that the state could move ahead with its healthcare vaccine mandate, which like Maine’s did not allow religious exemptions. A lower court judge had ruled the state had to allow such exemptions.