TORONTO -- The chief executive of the fund that manages Canada Pension Plan investments has resigned after it was revealed that he decided to travel to the United Arab Emirates, where he arranged to be vaccinated against COVID-19.

CPP Investments said Friday that Mark Machin tendered his resignation after discussions with the board Thursday night.

The resignation comes after Machin on Thursday evening sent a memo to staff, in which he said he received a COVID-19 vaccination while on a "very personal" trip to Dubai.

Machin said in the email viewed by The Canadian Press that he remains in Dubai with his partner "for many reasons, some of which are deeply personal."

"This was a very personal trip and was undertaken after careful consideration and consultation," the memo reads.

The federal government is actively discouraging Canadians from travelling abroad and recently implemented stricter quarantine measures for those returning home.

Machin told staff he followed all travel protocols related to his role as head of the pension fund while on the trip.

"This trip was intended to be very private and I am disappointed it has become the focus of public attention and expected criticism," he wrote.

Several politicians and health-care officials have become high profile flashpoints in recent months for leaving the country despite public health advice to the contrary.

Among them, the former CEO of the London Health Sciences Centre is now embroiled in litigation after his travel to the U.S. prompted the hospital to terminate his contract.

Rod Phillips, Ontario's former finance minister, resigned from his post in late December after taking a personal trip to St. Barts.

A spokeswoman for Finance Minister Chrystia Freeland said that while CPPIB is an independent organization, the revelation is "very troubling."

"The federal government has been clear with Canadians that now is not the time to travel abroad," Katherine Cuplinskas said in an emailed statement.

"We were not made aware of this travel and further questions should be directed to the CPPIB on this matter."

CPP Investments said Friday it has no comment beyond the statement announcing Machin's departure.

The fund's board has appointed John Graham as its new CEO. Graham was its global head of credit investments.

CPP Investments, which had $475.7 billion in assets under management as of Dec. 31, invests money on behalf of retired and active employees covered by the Canada Pension Plan.

Machin joined CPP Investments in 2012 and was appointed president and chief executive in June 2016. Before joining the pension fund manager, he spent 20 years at investment bank Goldman Sachs.

"The board wishes to thank Mr. Machin for his global perspective, leadership and commitment to excellence and we offer him our sincere best wishes for the future."

This report by The Canadian Press was first published Feb. 26, 2021