The condition forced him to cancel several events earlier this year.
Pope Francis is welcomed at Baghdad International Airport by Iraqi Prime Minister Mustafa al-Kadhimi on Friday, March 5.
Iraqi Foreign Minister Fuad Hussein said Iraqis were eager to welcome Francis' "message of peace and tolerance" and described the visit as a historic meeting between the "minaret and the bells".
Francis' determination to travel to areas long shunned by foreign dignitaries has impressed many in Iraq - as has his planned meeting with Sistani, 90, the top authority for Iraq's Shias.
Francis' plane touched down at Baghdad's airport just before 2 p.m. local time (1100 GMT).
At the airport, Francis stripped off his white mask - matching his pristine papal robe - to smile warmly at the children in folkloric dress who had gathered to greet him. "We are excited, and we all need this visit, all Iraqis do", said an Iraqi Christian from Baghdad, Magin Derius.
In central Tahrir square, a mock tree was erected emblazoned with the Vatican emblem, while Iraqi and Vatican flags lined empty streets.
Iraqi President Barham Salih also welcomed the pope's visit and said: "The continued migration of Christians from the region will have a detrimental impact on us all". A contrasting note came Wednesday from Abu Ali al-Askari, a spokesman for Kata'ib Hezbollah, one of the largest Iranian-allied militant groups in Iraq and one of the groups that the USA bombed in retaliation for last month's rocket attack.
"What we're really concerned about is saving people's lives and the sectarian violence in Iraq that has literally claimed thousands", Hussain said. The high stakes will give Iraqi forces motivation to ensure this visit is a showpiece of safety and peace.
No pope has ever made an official visit to Iraq.
The aim of Francis' visit, he said, is to encourage them to "hold onto hope".
Iraq endured decades of war, is still hunting for Deash cells and is now facing a second spike of Covid-19 infections, with more than 5,000 new cases and dozens of deaths daily.
The Vatican had defended going ahead with the trip despite Iraq's worsening coronavirus outbreak, saying social distancing and other health measures would be enforced.
Just like Iraq's Christian population, the esoteric Yazidi community was ravaged in 2014 by the Daesh group's sweep over much of northern Iraq.
After ISIS was defeated, many Christians in the country's north have been unwilling or unable to return to their liberated towns on the Nineveh Plain or in Mosul. Returnees have had to contend with more struggles.
Christians in Iraq enjoyed protection and near-equal rights with Iraq's Muslim majority under Saddam but were among the first groups targeted amid the breakdown in security and sectarian bloodbath that prevailed for years after the 2003 USA -led invasion that overthrew him. Today the number is believed to be around 250,000.
He said: "The day after tomorrow, God willing, I will go to Iraq for a three-day pilgrimage".
"I do hope to have the chance to come to you in person and to visit and to comfort you", he said.
Christians and Yazidis want to be involved in the decision-making about the future of the country, but they have not been given a seat at that table, she said.
"Pope Francis' insistence on conducting the visit, despite the many challenges, is a reflection of his complete faith in human fraternity as well as his willingness to uphold equality in the face of hatred, sectarianism and conflict".