CNN Business  — 

The White House turned up the pressure on Silicon Valley to get a handle on vaccine misinformation Thursday, specifically singling out 12 people one group dubbed the “disinformation dozen,” saying they were responsible for a great deal of misinformation about Covid-19.

“There’s about 12 people who are producing 65% of anti-vaccine misinformation on social media platforms,” White House Press Secretary Jen Psaki said Thursday.

That statistic is from the nonprofit Center for Countering Digital Hate (CCDH) which identified in a report published in March about a dozen people it said were super-spreaders of anti-vaccine misinformation.

The CCDH had at the time called on Facebook and Twitter to shut down all pages run by those people.

Robert F. Kennedy Jr., a prominent figure in the anti-vaccine movement, is among the people whom the CCDH said should be kicked off social media.

Kennedy’s page on Facebook (FB)-owned Instagram was shut down earlier this year for sharing Covid-19 misinformation, Facebook (FB) said. However, Kennedy is still allowed on Facebook (FB) itself, and he has more than 300,000 followers on the platform.

Robert F. Kennedy Jr., nephew of former U.S. President John F. Kennedy and a prominent figure in the anti-vaccination movement, in 2020.

Explaining why Kennedy was kicked off one of its platforms but not the other, a Facebook spokesperson told CNN Thursday, “We don’t automatically disable accounts across our apps, because the accounts may post about different things on our different services.”

At the time the CCDH’s report was released in March, Kennedy told NPR that he had become more cautious on Facebook, which according to NPR he also accused of censorship. “I have to post, like, unicorns and kitty cat pictures on there,” he said.

The CCDH said Friday that 35 social media accounts tied to the people it identified have now been shut down, losing them 5.8 million followers, but 62 accounts with a total of 8.4 million followers are still active.

CNN reported Thursday that meetings between the Biden administration and Facebook have grown “tense,” according to a person familiar with the conversations.

The person pointed specifically to Kennedy’s still-active Facebook account as an example of what some White House officials view as Facebook’s inaction regarding Covid-19 misinformation.

A Facebook spokesperson told CNN Friday the company had shut down some pages and groups belonging to the dozen or so people identified by the CCDH but would not say what pages.

A spokesperson for Twitter (TWTR) did not immediately respond to a request for comment.