Life in the Grey Zone (Življenje v Sivi Coni), written by a doctor who worked at the Covid ward of the University Medical Centre in Ljubljana, has been declared book of the year at the Slovenian Book Fair after becoming an overnight bestseller.

A young doctor specialising in infectology at the hospital's Infectious Diseases Department, David Zupančič was the one who confirmed Slovenia's first case of Covid-19 at the start of the pandemic in 2020.

He started writing down his thoughts in a cheeky way, convinced that humor is an important part of life.

"There are lots of comical situations in medicine and healthcare, but writing about them requires a great deal of empathy and, above all, self-criticism," he told the STA.

"You have to make sure that it's respectful to everyone involved and to the profession. I'm very careful not to trivialise," he said.

Publisher Mladinska Knjiga said the book was a complete surprise since it sold out in less than two weeks, becoming their fastest selling book in eight years.

According to editor Alenka Kepic Mohar, the author drives home the universal message that it is important to work with the heart, which he conveys convincingly.

Receiving the award on 25 November, Zupančič said he had felt the book had the potential to be read, but "one does not dare hope for" such a huge response.

Asked whether he is considering writing another book, he said he is very much motivated to go on, and "in my head I already have a direction in which I'd like to go".

The winner was chosen from ten nominees by members of the public in an online vote. More than 4,000 people voted on the festival's website, and Zupančič's book received over 40%.

Zupančič was a prominent presence on social media even before the book came out. He has a popular account on Instagram and is also the author of the podcast The Art of Laziness.