The doctor treating Niki Lauda has confirmed pneumonia is not the cause for the continued stay in a hospital in Vienna.

On Wednesday, two Austrian media outlets reported the three-time Formula 1 champion's condition had worsened upon being re-admitted last weekend with a bout of the flu.

Concerns were then raised after it emerged Lauda would be remaining under observation for longer than initially expected and his specialist physician Walter Klepetko has admitted his patient is suffering from "more than a cold".

However, he reassured his illness hadn't worsened to pneumonia and also revealed Lauda was breathing without ventilation.

"Because of the [lung] transplant [Niki had last summer], the situation is more complex than with a healthy person," Klepetko noted.

The doctor also remains positive about Lauda's chances of recovery adding: "Niki was looking after his health and doing everything right. In his situation, certain risks are inevitable."

The Mercedes non-executive chairman is still expected to be released from hospital in the coming days and is almost certainly still targeting a return to the F1 paddock in Australia in March.

Let's hope that's the case!