Ammon News - Pope Francis, who is spending his fifth day in hospital for what doctors described as a "complex" respiratory infection, will not take part in this weekend's Holy Year events, the Vatican said on Tuesday.

The 88-year-old pontiff has been suffering from a respiratory infection for more than a week and was admitted to Rome's Gemelli hospital on February 14.

A public papal audience set for this Saturday has been cancelled "due to the health condition of the Holy Father", the Vatican said in a brief statement.

The Vatican said on Monday that doctors had changed the pope's drug therapy for the second time during his hospital stay to tackle a "complex clinical situation". They described it as a "polymicrobial infection of the respiratory tract".

Doctors says a polymicrobial infection is one caused by two or more micro-organisms, and can be caused by bacteria, viruses, or fungi.

Francis, who has been pontiff since 2013, has had influenza and other health problems several times over the past two years. As a young adult he developed pleurisy and had part of one lung removed, and in recent times has been prone to lung infections.

The Vatican, which has said Francis will stay in hospital for as long as necessary, was yet to give a medical update on his condition on Tuesday. It was expected to come by the afternoon.

The Vatican has not specified whether the pope is suffering from a bacterial or viral infection.

While a bacterial infection can be treated with antibiotics, viral infections cannot. Viruses usually have to run their course, but the patient can be assisted with other medicines to bring down a fever or help their body fight the infection.

On Monday, the Vatican said the pope had eaten breakfast, an indication that he was not on a respirator and was well enough to digest food. Reuters