That miracle, which dates back to February 2014, saw the boy being “fully cured” after he touched Carlo’s relic and said “stop vomiting”, a priest and family friend of Mattheus’s said.
The second miracle saw a girl from Costa Rica who was studying in Italy reportedly being healed after suffering a head trauma.
She was reportedly cured by the boy after he was invoked by her mother, Avvenire, the daily newspaper of the Italian Bishops’ Conference (CEI), reports.
Pope Francis took the decision to attribute the second miracle to Carlo during a meeting with the head of the Vatican’s saint-making department, Cardinal Marcello Semeraro.
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The attribution of a second miracle means the boy can now be elevated to sainthood, but the Vatican did not say when this would happen.
The Roman Catholic Church teaches that only God performs miracles, but that saints who are believed to be with God in heaven intercede on behalf of people who pray to them.
Typically, miracles are the medically inexplicable healing of a person.
Due to his “important role in evangelisation through the internet”, Carlo was named as a patron of last year’s World Youth Day in Lisbon, organisers of the event said.