The Microsoft cofounder announced his condition on Twitter, saying that he is “experiencing mild symptoms and am following the experts’ advice by isolating until I’m healthy again.”

“I’m fortunate to be vaccinated and boosted and have access to testing and great medical care,” he added in a separate tweet.

He noted that the Gates Foundation, which he cofounded with his former spouse Melinda French Gates, was meeting in-person on Tuesday “for the first time in two years, and I am lucky to be on Teams to see everyone and thank them for their hard work,” referring to Microsoft’s video conferencing service.

“We will continue working with partners and do all we can to ensure none of us have to deal with a pandemic again,” said Gates, who published a book this week titled, How to Prevent the Next Pandemic.

On Sunday, Gates, speaking on CNN, discussed how COVID-19 has led to an explosion of digital services, helping people and companies connect and interact with each other without having to be nearby. He believes that the increased use of digital tools will not subside after the COVID-19 pandemic, and will instead be permanent.

“I think that is a very positive thing,” Gates said during the interview. “And the software involved is going to get a lot better. I wouldn’t underestimate that accelerated digitization including in health and education substantially.”

Earlier in May, Gates discussed with the BBC his association with many COVID-19 conspiracy theories, which sometimes results in people yelling at him on the street.

“You almost have to laugh because it’s so crazy,” Gates said.