Howe fell ill last week and was admitted to hospital on Friday, where he spent the weekend.
The Toon manager missed Sunday's win against Manchester United and it's now been confirmed he is recovering from pneumonia.
"A huge thank you to everyone connected with Newcastle United and the wider football community for your messages and warm wishes. They have meant a lot to me and my family," Howe said in a statement issued by the club.
"I also want to pay tribute to our incredible NHS and the hospital staff who have treated me.
"I'm immensely grateful for the specialist care I'm receiving and, after a period of recovery, I look forward to being back as soon as possible."
Assistant manager Jason Tindall will remain in charge for this week's Premier League games with Crystal Palace and Aston Villa.