British researchers are hotly contesting allegations that they short-circuited ethical procedures in research involving children at the Nyumbani orphanage in Nairobi, Kenya.

The centre has attracted international interest because some of the children there who have AIDS seem to control their HIV infection without drug therapy, and survive beyond their expected lifespan with a relatively intact immune system.

On 23 May, the Nairobi-based Sunday Nation ran a story under the headline “Shame of children used in experiments on Aids”. In it, the paper alleged that Eric Miller, a researcher from the University of Cambridge, carried out research at the orphanage in April without government approval. It also claimed that a group from the University of Oxford that visited the centre in 2001 had exported blood samples without permission.

Kenya's National Council for Science and Technology is looking into the allegations. But Ababu Namwamba, a lawyer representing the orphanage, says that the allegations are groundless and originate from a disgruntled former employee. In a statement prepared by Namwamba, the centre says that Miller did no research and only visited the orphanage “on a fact-finding mission” with a view to future research on the impact of food supplements on HIV progression.

The Oxford group's work, which resulted in two research papers, received ethical clearance from the national council on 8 January 2001, according to the centre. It admits that the original proposal omitted to request specific consent to send samples to Oxford, but says that once this oversight was spotted, Nyumbani and the university immediately told the council, and got ethical approval in September 2002.

In a letter addressed to the Nation last week, the Oxford researchers involved, Sarah Rowland-Jones and Rana Chakraborty from the Medical Research Council's Human Immunology Unit, added that once they had discovered the discrepancy, they “called an immediate halt to all research and export of samples until the matter could be cleared up”.

The orphanage says that it “experienced the spreading of malicious propaganda”, after it fired a scientist in 2001. It adds that it wants the government to investigate the matter so that it can clear its name.