The recent update from the Vatican is that the pontiff suffered from an 'isolated breathing crisis' that led to him vomiting. It apparently caused  a 'sudden worsening' of his respiratory condition. 

On Friday afternoon, after the pontiff spent his time alternating 'respiratory training' with a 'prayer' at the hospital, he apparently 'inhaled the vomit' that led to the 'sudden worsening' of his respiratory health. 

Doctors proceeded to give him a 'non-invasive mechanical ventilation' to help him to breathe, to which his body showed 'a good response', Vatican stated, adding that the pope remains 'alert and well-oriented' as the treatment continues. 

However, this is seen as a setback in what had been two successive days of "getting better" reports from doctors treating him at Rome's Gemelli Hospital.  The episode, which occurred in the early afternoon and described by doctors as an "isolated crisis of bronchial spasm", resulted in a sudden worsening of the respiratory picture, according to the Vatican. Doctors decided to keep the pontiff's prognosis as guarded and indicated they needed 2-48 hours to evaluate how and if the episode has impacted his overall clinical condition. 

People have been gathering outside Rome's Gemelli hospital to show their support, with many leaving messages and notes near a statue of former Pope John Paul II.

The Vatican has said Pope Francis is thankful for the "closeness he feels" from his supporters, and that he asked for people to pray for him.