(Reuters) - Meta Platforms defeated an appeal by Children's Health Defense, an anti-vaccine group founded by Robert F. Kennedy Jr., challenging its censorship of Facebook posts that spread misinformation about vaccines' efficacy and safety.

In a decision on Friday, the 9th U.S. Circuit Court of Appeals in Pasadena, California, said the nonprofit did not show that Meta worked with or was coerced by federal officials to suppress views challenging "government orthodoxy" on vaccines.

Children's Health Defense sued in 2020, saying that Meta had violated its constitutional rights by flagging "vaccine misinformation" as false, and taking away its right to advertise on Facebook.

Meta's actions included prohibiting users from sharing claims that COVID-19 vaccines don't work, and referring viewers of Children's Health Defense posts to the World Health Organization for facts about COVID-19.

Circuit Judge Eric Miller, appointed to the court by Republican former President Donald Trump, wrote for the appeals court that Meta was a "purely private" company with a First Amendment right not to use its platform to promote views it found distasteful.

"Meta evidently believes that vaccines are safe and effective and that their use should be encouraged," Miller wrote. "It does not lose the right to promote those views simply because they happen to be shared by the government."

The court also rejected Children's Health Defense's claims against the Poynter Institute and Science Feedback, which help Meta evaluate the accuracy of Facebook content.

Kennedy, an independent U.S. presidential candidate, helped argue Children's Health Defense's appeal. Meta removed the group's accounts from Facebook and Instagram in August 2022.

Children's Health Defense did not immediately respond to requests for comment. Neither Meta nor lawyers for the Menlo Park, California-based company immediately responded to similar requests.

Circuit Judge Daniel Collins, also a Trump appointee, dissented from Friday's decision, saying that Children's Health Defense could seek an injunction on its free speech claims. He agreed that its other claims, including for monetary damages, should be dismissed.

Friday's decision upheld a June 2021 ruling by U.S. District Judge Susan Illston in San Francisco.

The case is Children's Health Defense v Meta Platforms Inc, 9th U.S. Circuit Court of Appeals, No. 21-16210.