YouTube, Google’s online video hub, has stopped ads from running on videos pushing anti-vaccination, or “vaccine hesitancy,” theories as part of its push against misinformation, preventing individuals and groups from making money on the site.

“We have strict policies that govern what videos we allow ads to appear on, and videos that promote anti-vaccination content have been, and remain, a violation of our longstanding harmful or dangerous content advertising policy,” a YouTube spokesperson said. “We enforce these policies vigorously, and if we find a video that violates them we immediately take action and remove ads.”