(Reuters) - Embattled Fox News TV anchor Bill O’Reilly maintained strong viewership ratings ahead of his two-week vacation, even after more than 50 advertisers pulled their commercials from “The O’Reilly Factor” news show, according to Nielsen.

FILE PHOTO - Fox News Channel host Bill O'Reilly poses on the set of his show "The O'Reilly Factor" in New York March 17, 2015. REUTERS/Brendan McDermid/File Photo

Fox News parent Twenty-First Century Fox Inc FOXA.O is investigating sexual harassment claims against O'Reilly, who has said that he was unfairly targeted because of his public prominence.

O’Reilly’s ratings have remained strong with an average of 3.7 million viewers last week, up from the prior week and leading all other cable news programs, according to Nielsen.

The “O’Reilly Factor” continued that pace this week, averaging 3.7 million on Monday and Tuesday, the media tracking firm said on Wednesday.

O’Reilly said on Tuesday’s show that he usually takes time off during the spring. “Often around this time of year, I grab some vacation because it’s spring and Easter time,” he said. “We all need R&R.”

A report in New York magazine said some Fox executives, including CEO James Murdoch, want O’Reilly gone from the network permanently.

A Fox News spokesperson told Reuters that O’Reilly will return on April 24 and a rotating cast of guest hosts will fill in during his absence.

According to ad-tracking firm Kantar Media, ad time on “The O’Reilly Factor” has fallen by more than 50 percent, bottoming out with just seven ads during Friday’s show. Before the harassment allegations were reported in the media, the show averaged 33 national spots, said Kantar.

Most of the advertisers on “O’Reilly Factor” last week were smaller companies such as Visiting Angels Home Health Services, MyPillow.com, and gold retailer Rosland Capital.

After advertisers including AllState Corp ALL.N and T. Rowe Price TROW.O pulled their ads from the show, Fox News Executive Vice President of Ad Sales Paul Rittenberg said advertising had moved to other Fox News programs.