The Vatican says it is impossible to protect the Pope from incidents like that on Thursday night, when a woman grabbed him at Mass on Christmas Eve.
Spokesman Frederico Lombardi said the Pope Benedict XVI was regularly surrounded by thousands of people at audiences, Masses, greetings and other events.
He said it was unthinkable to create a wall between the Pope and the faithful.
The Pope was not injured when Susanna Maiolo, 25, hurled herself at him in St Peter's Basilica at the Vatican, but Cardinal Roger Etchegaray, 87, of France, suffered a broken hip.
The woman also tried to throw herself at Benedict at the same Christmas Eve service last year. She is now receiving psychiatric treatment.
La Repubblica newspaper reports that she has told doctors she did not want to harm the pope.
Father Lombardi said it was not realistic to think the Vatican could ensure 100% security for the Pope and that security guards appeared to have acted as quickly as possible.
He said the Vatican is likely to be very lenient and she will be pardoned.
The BBC reports the most serious attack on a Pope in modern times was that on Benedict's predecessor, John Paul II, who was shot and seriously wounded by Turkish gunman Mehmet Ali Agca in 1981 as he rode in an open jeep in the Vatican.
In his annual Christmas message on Friday, Pope Benedict called on the world to abandon violence and vengeance.
The pontiff said today's world has to rediscover the simplicity of the Christmas message.
While the world is steeped in a grave financial crisis, he said it is also affected even more by a moral crisis.