How can the Catholic Bishops’ Conference in Kenya jeopardise the lives and well-being of children by promoting a boycott of a polio immunisation programme? (Letters, 8 August). It is totally outside their competence to make a judgement on a medical matter of this nature. As was pointed out by Sr Gillian Price, this vaccine to eradicate polio has been vigorously tested by competent health authorities. As leaders of Christian communities in Kenya surely it is the duty and responsibility of the Bishops’ Conference to promote, encourage and support this programme.Sr Margaret Healy SSL, London N14 I was a paediatrician in Africa and am now retired. Unfortunately, fears that polio immunisation was being used as a cloak for covert mass sterilisation have arisen in several countries,