In his video, George R.R. Martin mentioned that he is fully vaccinated & boosted for COVID, and casually described his condition as:
"I feel a little sniffle-y, but really nothing bad. I've had worse colds."
Prior to catching COVID, George R.R. Martin attend San Diego Comic-Con 2022, skipping every party and event out of caution, save for the House of the Dragon Full Panel; where Ron asked this question:
Ron: Will we see you in a cameo?
GRRM: I don't know, I mean; for the last couple of years since COVID hit, I've hardly left my house. I've been, you know, trying to stay away from COVID and, also you may not know but there's this book I'm writing, it's a little late and I don't see me visiting the set or doing anything until, until I finish and deliver that book, and then if the show is still going, who knows, maybe I'll show up.
Back on April 29, 2022, George R.R. Martin did tease details about "Winds of Winter", writing:
THE WINDS OF WINTER is going to be a big book. The way it is going, it could be bigger than A STORM OF SWORDS or A DANCE WITH DRAGONS, the longest books in the series to date. I do usually cut and trim once I finish, but I need to finish first.