Pope Francis remains hospitalized with a severe lung infection, but while clear procedures exist for the resignation or death of a pope, no specific laws define how leadership is handled if the leader of the Catholic Church is unconscious or unable to govern.

The pontiff's condition is touch-and-go, given his age, fragility and pre-existing lung disease, according to doctors.

Pietro Parolin, a 70-year-old Italian polyglot who entered the seminary at just 14, is currently pitted as favourite to replace Francis as the pope is still in hospital.

Renewed interest in Vatican tradition on back of Conclave winning at the Baftas and updates on Pope Francis’ health

Vatican officials said that Pope Francis had developed pneumonia in both lungs, further complicating the pontiff’s recovery

The Vatican was "utterly let down" by an Italian financier over the Catholic Church's botched investment in a high-end London property, a judge ruled on Friday following a trial at which a senior aide to Pope Francis gave evidence.

As the pope enters his second week in a Rome hospital with a lung infection, his physicians said his condition was critical but not immediately life-threatening.

The kidney ailment appears to be in an early stage, the Vatican said, adding that the pontiff is still receiving high flows of oxygen for his respiratory illness.

LONDON — Vatican officials said late Tuesday that Pope Francis had developed pneumonia in both lungs, further complicating the pontiff’s recovery. The 88-year-old pope was hospitalized Friday after a weeklong bout of bronchitis worsened. On Monday, doctors said he had developed a mix of infections in his respiratory tract.