UPDATED: Amazon has yanked at least five anti-vaccination documentaries questioning the safety of vaccines from its Prime Video streaming platform.

The move came just hours after U.S. Rep. Adam Schiff (D-Calif.) publicly announced that he’d sent a letter to Amazon CEO Jeff Bezos expressing concern that Amazon is “surfacing and recommending products and content that discourage parents from vaccinating their children.”

The anti-vax documentaries had been available in the U.S. as part of Prime Video but as of Friday afternoon were not available to stream. Those include “Vaxxed: From Cover-Up to Catastrophe”; “We Don’t Vaccinate!”; “The Greater Good”; “Shoot ‘Em Up: The Truth About Vaccines,” a purported exposé on the danger vaccines pose by potentially contributing to autism, asthma and neurological damage; and “Man Made Epidemic,” described as an investigation into “the autism epidemic and whether MMR vaccines have a role to play.”

“Vaxxed,” directed and written by leading anti-vax proponent Andrew Wakefield, questions the link between vaccinations and autism. It was selected to be screened at the 2016 Tribeca Film Festival before a backlash prompted festival co-founder Robert De Niro to drop it from the lineup. Following the controversy, the film’s distributor gave it a limited theatrical release.

Amazon reps did not respond to requests for comment. Amazon’s removal of the anti-vax documentaries from Prime Video was first reported by BuzzFeed News.

While the anti-vaccination movies were no longer available on Prime Video, DVDs of the titles remained available for purchase on Amazon (with the exception of “We Don’t Vaccinate!”). The ecommerce behemoth also continues to list multiple anti-vax books for sale on the site.

Earlier Friday, Schiff announced the letter addressed to Bezos, which said in part, “There is strong evidence to suggest that at least part of the source of [the anti-vaccination] trend is the degree to which medically inaccurate information about vaccines surface on the websites where many Americans get their information, among them Amazon. As the largest online marketplace in the world, Amazon is in a unique position to shape consumption.” He also cited a CNN report that Amazon accepts paid advertising that contains misinformation about vaccines.

Two weeks ago, Schiff also had sent a letter to Google and Facebook requesting details on how the companies planned to combat the spread of information discouraging parents from vaccinating their children.

As Schiff noted in each of the letters to Amazon, Facebook and Google, there’s overwhelming scientific and medical evidence that childhood vaccinations are both safe and effective at curbing disease outbreaks. He also cited Washington State’s declaration of a public health emergency due to a measles outbreak in Clark County, “signaling the resurgence of a potentially fatal disease that was effectively eliminated from the United States decades ago by vaccines.”

Last week, YouTube said it will no longer serve ads on channels that espouse anti-vaccination rhetoric. The Google-owned video giant cited its advertising policy that bans “dangerous and harmful” content from eligibility in its monetization program. Facebook has said it is working to “reduce the distribution of health-related misinformation” on the platform.

Separately, Pinterest recently implemented a change to block all vaccination-related searches on its image and video-sharing platform, as first reported by the Wall Street Journal.