“I guess I’m not always the boss at my own house,” Mr Kennedy told Politico when asked about last week’s invitation.
Mr Kennedy added that the party was for his wife’s friends in the entertainment industry and that he didn’t know what the invitation had said until the day of the party. Mr Kennedy is married to actress Cheryl Hines, who has worked on Curb Your Enthusiasm.
Mr Kennedy claimed that there had been no effort made to verify vaccination or testing status before allowing attendees to enter the California home.
“Robert Kennedy Jr would make his father turn over in his grave,” a Twitter user wrote. “He is responsible for mass outbreaks of measles, and now covid. He’s clearly in need of a mental health check.”
“I don’t understand this. How can a person be pro covid testing and vaccination and be married to one of the biggest anti-vaxxers in the country?! Y’all go too far with that difference of opinion bulls**t,” another added.
Writer Garance Franke-Ruta said the episode revealed that Mr Kennedy’s “anti-vaxism” was “masculine self-promotional theater rather than an actual lifestyle”.
Journalist Juwan Holmes tweeted that “Jeff Garlin got dumped from ABC earlier this week for not respecting boundaries and Cheryl Hines is living with the nation’s most prominent anti-vaxxer, if that’s any indication of what the Curb Your Enthusiasm set is like recently”.
Lawyer Eric Columbus added: “Looks like RFK Jr married up, which I guess is the only way he could have married.”
The revenue of Children’s Health Defense, Mr Kennedy’s anti-vaccine group, more than doubled last year to $6.8m, the Associated Press reported.
Mr Kennedy released a book last month, which is still a bestseller on Amazon, entitled The Real Anthony Fauci: Bill Gates, Big Pharma, and the Global War on Democracy and Public Health.
Children’s Health Defense has since the start of the pandemic grown the influence of its newsletter and started an online TV channel and a movie studio. It has opened new offices in the US but now also has a presence in Canada, Europe, and Australia. The group is translating articles into French, German, Italian, and Spanish.
The group’s website has become one of the most used sites in the world for “alternative and natural medicine”, data from Similarweb, a digital intelligence company, show.
Its articles now get millions of visitors every month, compared to less than 150,000 before the pandemic. Many of their pieces instil doubt about vaccines.
Experts have said that the group has targeted groups that may be more likely to distrust the vaccines with false claims about the inoculations. Some worry the approach could lead to further deaths in a pandemic that has already taken more than five million lives.
While Mr Kennedy has been active in the anti-vaccine movement for some time, the Covid-19 pandemic has taken him to new heights, doctors and public health officials have said.
Vaccines prevent as many as 5m deaths every year, according to the World Health Organization.
“Probably I’ve lost 80 per cent of my income because of what I’m doing, along with a lot of friendships and, you know, and damaged relationships even with people in my family,” Mr Kennedy told conspiracy outlet InfoWars this month.
His sister, Kerry Kennedy, indicated to the AP that her brother using the legacy of their uncle, President Kennedy, to push anti-vaccine conspiracy theories is insincere.
“Anyone who believes this does not know their history. Vaccinations were a major effort of John F Kennedy, both as a senator and later as president,” she said.
“I love Bobby, I think he’s just completely wrong on this issue and very dangerous,” she added. “Failure to take vaccines puts people’s lives at risk. It not only impacts the person who refuses the jab but imperils the community at large.”
The Independent has reached out to Children’s Health Defense for comment.