Niki Lauda has hit a roadblock on his road to recovery following the lung transplant undergone by the F1 legend last summer.
The Mercedes non-executive chairman has been slowly but surely putting himself on the mend after a critical condition diagnosed in July led to heavy surgery for the Austrian.
While the transplant was deemed a success, Lauda underwent a lengthy convalescence period in intensive care and then at his home in Austria.
However, progress enabled the three-time world champion to travel to Ibiza in December where he unfortunately contracted a flu virus while celebrating Christmas with his family, a state of affairs that was bad news for Lauda's vulnerable immune system.
According to a report from Austria's Krone, the former driver was transported earlier this week back to the intensive care unit of Vienna's AKH hospital.
Lauda, who will be 70-years-old on February 22, had tentatively scheduled a return to the paddock for Melbourne, but that target may have to be pushed back following his latest medical setback.