The official Twitter account for Shueisha's Weekly Shonen Jump magazine revealed on Thursday that Gege Akutami's Jujutsu Kaisen manga will go on hiatus beginning with the magazine's 29th issue on June 21 due to Akutami's poor health. The magazine will announce when the manga will return at a later date once Akutami has sufficiently recovered. A new chapter of the manga will still appear next week on June 14.
Akutami added that the manga's hiatus will be "around a month." He also noted that his condition was not serious, and that he was still mentally healthy.
Viz Media publishes the manga in English and it describes the story:
In a world where demons feed on unsuspecting humans, fragments of the legendary and feared demon Ryoma Sukuna were lost and scattered about. Should any demon consume Sukuna's body parts, the power they gain could destroy the world as we know it. Fortunately, there exists a mysterious school of Jujutsu Sorcerers who exist to protect the precarious existence of the living from the supernatural!
Yuji Itadori is high schooler who spends his days visiting his bedridden grandfather. Although he looks like your average teenager, his immense physical strength is something to behold! Every sports club wants him to join, but Itadori would rather hang out with the school outcasts in the Occult Club. One day, the club manages to get their hands on a sealed cursed object, but little do they know the terror they'll unleash when they break the seal...
Akutami launched the manga in Shueisha's Weekly Shonen Jump magazine in March 2018. Shueisha published the manga's 16th compiled book volume on June 4. The manga has over 50 million copies in circulation.
Viz Media published the manga's first three chapters in English simultaneously with Japan as part of its Jump Start initiative. When Viz then switched to its new Shonen Jump model in December 2018, the company began publishing new chapters of the manga digitally. Shueisha is also publishing the manga on its MANGA Plus website.
The Jujutsu Kaisen anime premiered on October 2 last year, and it had 24 episodes. Gekijō-ban Jujutsu Kaisen 0 (Jujutsu Kaisen 0 the Movie), a new anime film for the franchise, will open this winter. The film is based on Gege Akutami's Jujutsu Kaisen 0 Tokyo Toritsu Jujutsu Kōtō Senmon Gakkō (Jujutsu Kaisen 0: Tokyo Prefectural Jujutsu High School) manga prequel story.
Update: Added Akutami's comment on hiatus' duration.
Sources: Weekly Shonen Jump's Twitter account, The Mainichi Shimbun's Mantan Web