"The pope was very interested in our suggestion and asked us what date we would like the day to be," Consolata Sister Eugenia Bonetti told Catholic News Service.
"We told him Feb. 8 -- the feast day of St. Josephine Bakhita," a Sudanese slave who found freedom in Italy and became a nun in the late 19th century.
She said the idea for a worldwide day of prayer came from "the need to do something that joins us together" to tackle the global problem; some dioceses and parishes are active on the issue while others are unaware or indifferent, she said.
Sister Eugenia, a leader among religious women in Italy working against human trafficking -- particularly women and young girls forced into prostitution -- was one of about 80 people attending a Nov. 2-3 working group on trafficking at the Vatican.
She talked to CNS Nov. 3 about her informal meeting with Pope Francis in late September when she and three other sisters from different religious congregations were invited to attend the pope's early morning Mass at his Vatican residence.
They had written the pope thanking him for his work and focus on the marginalized, and alerted the pope about the need for greater involvement by the church, especially by religious congregations of men, parish priests and schools in curbing the demand for prostitution by promoting a "culture of respect."
Sister Eugenia, who together with some 250 women religious through the Union of Major Superiors of Italy, has spent the past two decades fighting the illegal sex trade and helping victims.
She said that after the Mass she and the three sisters presented the pope with a signed poster, photographs and letters from women who have been rescued from traffickers, but are being held in a detention facility in Rome.
They also gave the pope a small white and blue rug that detainees had made by crocheting strips of paper bed sheets with a plastic fork, Sister Eugenia said.
The Vatican working group on trafficking was organized by the Pontifical Academy of Sciences, the Pontifical Academy of Social Sciences and the Vatican-based International Federation of Catholic Medical Associations.
Bishop Marcelo Sanchez Sorondo, chancellor of the academies, said Pope Francis had specifically asked him to have the academies study the problem of new forms of slavery, including the trafficking of people and human organs.
While he was archbishop of Buenos Aires, the future Pope Francis had been a strong supporter of local activists and initiatives fighting human trafficking and supporting rescued victims.
Bishop Sanchez told journalists Nov. 4 that the pope wants to see the working group's findings and recommendations, and that "he will do something important" with the information.
The pope told him recently that the academies' attention to the problem was very important to him and that the work that came out of it would be "valuable," the bishop said.
"The church as a whole isn't sufficiently aware of the problem" or hasn't focused deeply enough on how serious a problem it is, he told Vatican Radio Nov. 1.
Worldwide, at least 21 million people are victims of forced labor, including sexual exploitation, and traffickers bring in an estimated $32 billion annually because of their illicit activities, the U.S. State Department's 2012 Trafficking in Persons report said. An estimated 100,000 to 300,000 minors are victims of sex trafficking at any given time, according to the U.S. Justice Department.
The November meeting was the first time the Vatican academies had dedicated a session to studying human trafficking, the bishop said. They will have another meeting next year in the run-up to a larger gathering in 2015, the bishop told journalists.
"The pope, ever since he was an archbishop, had already intuited this serious social problem," Bishop Sanchez told Vatican Radio. "We were dumbstruck for not having figured it out beforehand."