Fox Corp. CEO Lachlan Murdoch has publicly endorsed a debunked conspiracy theory spread by Fox News prime time host Tucker Carlson, who has claimed that thousands of people died in connection with the COVID-19 vaccines.

Carlson has increasingly become the network’s top personality on TV and to push its online content, and he has used the platform to undermine the public vaccination campaign ever since last year. Other network figures have gotten their shots — most notably Fox News founder and Lachlan’s father Rupert Murdoch — while the network has continually taken pandemic health measures more seriously for itself than for its audiences. (Carlson has still not disclosed whether he has been vaccinated.)

For this latest example, Carlson has relied on a public system known as VAERS, or the Vaccine Adverse Event Reporting System, to which anybody can submit a report of health events. False claims surrounding the unverified database had been spreading for months online, from the likes of anti-vaccine conspiracy theorist Robert Kennedy Jr., frequent Fox News guest Alex Berenson, and prominent influencers in the far-right QAnon movement.

However, the system does not include any key context of what other factors might have contributed to an individual’s negative health events, and because it is publicly sourced it can include many errors. (For example, a report that a 2-year-old died after receiving a COVID-19 vaccine during clinical trials has been removed from the VAERS system for being “completely made up” — as vaccine trials for young children had not even begun yet when the report was filed.)

But when these problems were widely pointed out, Carlson only dug in further, asking, “What exactly are the real numbers? How much harm have the COVID vaccines caused?”

In an interview with Business Insider, Lachlan Murdoch stood by Carlson’s falsehoods:

Business Insider noted that “Factcheck.org denounced Carlson's statement, explaining that anyone can submit a report of an adverse side effect following vaccination, without verification or proof that it was caused by the vaccine.”

FactCheck.org listed some examples, as well:

And while Lachlan Murdoch characterizes the VAERS reports as “CDC data,” a disclaimer on the VAERS site actually makes clear: “The reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable” — which, come to think of it, would be a better slogan for Fox News.