Austen Ivereigh: Historic, and uttered nervously, but it offers nothing for those with Aids in Africa

The Pope's remarks on the use of condoms in the context of Aids have taken the world by surprise. It feels like a historic statement, one that shifts Catholic teaching in a whole new direction. Yet what Pope Benedict XVI told Peter Seewald in a book out on Tuesday would be unsurprising to most moral theologians. What is new is that the Pope has said it. And by saying it he has at last clarified and resolved a question over which there has been vigorous disagreement, even at high levels of the Church.

What has he said? He has repeated the Church's view – for which there is, incidentally, endless evidence – that condom-based campaigns are not the solution to Aids in Africa, and have aggravated the spread of virus. The solution lies in learning fidelity, monogamy and chastity. Condom campaigns, which give the opposite message – that casual sex is acceptable – undermine that solution.

So far, nothing new. But what he goes on to say is that in certain cases – he gives the example of a prostitute – using a condom to prevent infection may be the responsible thing to do, "the first step", as he says, "in the direction of a moralisation, a first assumption of responsibility, on the way toward recovering an awareness that not every- thing is allowed and that one cannot do whatever one wants".

This is significant because he is endorsing the view, expressed by many moral theologians over the years, that the use of a condom to prevent infection is of a different moral order from that of frustrating conception – it is not, therefore, contraceptive; and may, therefore, be licit.

What will it lead to? It will clear up, once and for all, the misperception that the Church's message to an HIV-positive prostitute is that he, or her client, shouldn't use a condom under any circumstances. The Church has never believed that, but the silence from Rome has allowed some conservative Catholics and Church critics to claim otherwise – giving the impression that it would rather a person be infected with Aids than prevent a pregnancy. As a Catholic commentator, that has been frustrating for me, and I am delighted Benedict XVI has cleared this up.

But it will change the way the Church goes about tackling Aids in Africa. The Pope's message to prostitutes or people in engaging in casual or risky sex is they should change their behaviour. But if that message is ignored, or people are not ready to hear it, the Pope is not telling them to refrain from using a condom.

In clearing up this up, the Pope is also sending a clear message: that the Church does not put its dogma before the lives of sufferers; and that taking responsibility for others is the first step in moral development.