“I underestimated how tough it would be to convince people to take the vaccine and continue to use masks,” Gates said.

But the Microsoft Corp. co-founder is optimistic about 2022, saying he’s hopeful the end is finally in sight. “I think the acute phase of the pandemic will come to a close some time in 2022,” Gates said.

The call comes as the world deals with a new variant. In the U.S. cases are are approaching 50 million.

“There’s no question that the Omicron variant is concerning,” Gates said. “But here’s what we do know: The world is better prepared to tackle potentially bad variants than at any other point in the pandemic so far.”

Separately, Gates touched on his divorce, saying he and Melinda French Gates continue to run their foundation together and have “found a good new working rhythm.”

“I can’t deny that it’s been a year of great personal sadness for me. Adapting to change is never easy, no matter what it is. I’ve been impressed by how resilient my loved ones—especially my kids—have been in this challenging time,” Gates said.