Niki Lauda's friend speaks about his "complex" health situation

More and more information has been slowly coming out over the past few days. It sounds like Niki Lauda's health situation is more serious than we first thought. His friend, Wolfgang Fellner has described the ordeal as "complect, heavy and serious" to Die Welt.

The Austrian underwent a lung transplant earlier this week. It's confirmed it wasn't related to his 1976 horror crash. In the past, the former driver and now Mercedes adviser had a kidney removal.

And it's this kidney removal that is making the situation worse. The heavy antibiotics required to prevent the virus may have damaged his single kidney.

Because of this, he spent 10 days on a heart-lung machine. It failed to help him and therefore needed the operation.

Lauda has had a heart attack in the past and had a heart bypass earlier this year. Before getting the virus, his state wasn't too good.