Vatican: Pope's condition stable
John Paul II to remain in hospital 'a few days'
Pope taken to hospital with what Vatican calls an acute respiratory infection.
Pope John Paul II suffers from a number of chronic ailments.
The worldwide influence of Pope John Paul II.
ROME, Italy (CNN) -- Pope John Paul II's condition stabilized Wednesday morning following overnight hospital treatment for an acute respiratory infection, a papal spokesman said.
The pope -- who was rushed to Rome's Gemelli Polyclinic around 11 p.m. Tuesday -- will remain there "a few days," according to a Vatican radio report.
After sleeping several hours, the pope ate breakfast, drank coffee and celebrated Mass with his private secretary in his hospital room, spokesman Joaquin Navarro-Valls said.
"Today there is no reason to be alarmed," Navarro-Valls said.
Although the pope has "a little fever," medical tests conducted early Wednesday showed his heart and breathing were within "normal limits," he said.
A source close to the Vatican confirmed to CNN that the pope received a flu shot before the flu season began last fall.
Earlier Tuesday, the Vatican said the pontiff had canceled his public and private meetings for the next few days, including his general audience on Wednesday, due to a bout with influenza.
"The pope joined the millions of Italians who have caught the flu," Navarro-Valls said Tuesday.
The pope's Vatican doctors decided he should be taken urgently to Gemelli Polyclinic Tuesday night after his symptoms worsened, sources said.
The pope has been treated at the Gemelli hospital in the past, but it is unusual for him to be rushed to the facility late at night.
Before the pope was taken to the hospital, Vatican sources said there was no reason for concern.
The decision to clear the pontiff's calendar came a day after the pope was forced to cancel his Monday meetings. At the time, the Vatican said John Paul had a mild fever.
They said the cancellations were made to give advance warning to the thousands of pilgrims who gather in St. Peter's Square each week to get a glimpse of the pope.
The pope last appeared in public Sunday. His voice was hoarse, but he appeared to be in good spirits.
His health has been relatively steady in recent months, and he looked in better health than during the summer and fall of 2003, when trips to Croatia and Slovakia appeared to take a heavy toll on the frail pontiff.
The last time health problems forced him to cancel an event was September 2003, when he was suffering from a intestinal ailment.
The pope suffers from a number of chronic ailments, including Parkinson's disease. He has survived an assassination attempt and undergone nine operations -- including a hip replacement.
The weather in Rome has been uncharacteristically cold the past few weeks, and Italian health officials had warned of a flu outbreak.
CNN's Rome Bureau Chief Alessio Vinci contributed to this report.