King Harald V of Norway, the oldest reigning head of state in Europe, has seen his condition worsen during his ongoing hospital stay, the royal palace in Oslo announced on Sunday. The 89-year-old monarch, who has been a patient at Oslo University Hospital since last Monday, is now being treated for a bacterial infection in the blood and is receiving antibiotics. The palace stated that he is responding well to the treatment and his condition has since stabilised.

Harald was initially admitted due to fluid retention — a side effect of cortisone treatment he had been receiving for complications linked to haemolytic anaemia, a form of anaemia in which red blood cells are destroyed faster than the body can produce them. The two-week medical leave comes against a backdrop of mounting health challenges for the monarch, who has ruled Norway since 1991. He received a pacemaker in March 2024 after falling ill during a holiday in Malaysia, and earlier this year was hospitalised in Tenerife with an infection.

During his current stay, Harald has received several family visits. Crown Prince Haakon and his wife Crown Princess Mette-Marit visited over the weekend, as did Queen Sonja and Princess Astrid, Harald's sister. Crown Prince Haakon has assumed his father's royal duties in his absence. Despite his recurring health difficulties, Harald has repeatedly ruled out abdication.

Why this matters: Harald's health is a matter of national concern in Norway, a constitutional monarchy on the Scandinavian Peninsula. As Europe's oldest reigning monarch, any serious deterioration draws significant public attention. Norway's royal family has faced a particularly turbulent period recently, adding weight to the king's hospitalisation at a sensitive moment for the institution.