"It is essential that the children know that someone is looking after them," explains Zaina Ahamed, a member of the team. "They eat a meal together, play games, participate in discussions and do drawing workshops. This way we give them time - time for them and not just for their mothers. We are alone with them, without their parents. They can say what they feel, ask their questions. We listen to them and respond to them. Without judging, without criticising. We are just there for them."

Between 100,000 and 150,000 children are estimated to be infected with HIV/AIDS in Kenya. 18,000 of these need ARV treatment. Yet only 1300 of them - less than 10% - are on it. According to the World Health Organisation (WHO), about 15% of all the people in the world requiring ARVs are children.

There are currently at least 1.4 million AIDS orphans in Kenya - at least one of the child's parents died from AIDS. Almost all children with HIV/AIDS were infected by their mothers.

"In the western world, mother-to-child transmission can be avoided in more than 99% of cases," explains Doctor Rachel Thomas, Coordinator of MSF's HIV clinic in Mbagathi Hospital. "Pregnant women infected with AIDS start their treatment earlier, they give birth by programmed caesarean and the new-borns receive powdered milk rather than breast milk, which carries transmission risks. The baby can also be tested early for HIVand start taking ARVs in time."

This is far from being the case in Kenya and elsewhere in Africa, yet this is where the crushing majority of HIV infected children are found. In Mbagathi, 95% of children infected by HIV contracted the virus during pregnancy, birth or breast-feeding.

Nearly 500 children under 13 years old are registered in the HIV/AIDS programme in Mbagathi Hospital. They represent about 10% of the patients. The real number needing treatment is certainly higher, but diagnosing the disease in young children is difficult. The HIV test relies on detecting certain antibodies produced if the virus is present in the blood.

The test does not work on children under 18 months old with seropositive mothers because they carry maternal antibodies in their blood. It is impossible to distinguish the child's antibodies from the mother's without access to a laboratory with highly technical and very expensive equipment. This is simply not available in the majority of developing countries.

Yet children cannot be allowed to wait: one child in two infected with HIV does not reach its second birthday.

The Mbagathi clinic launched an innovative project in September 2005 to break out of this deadlock. Supported by the Clinton Foundation, the project aims to detect HIV/AIDS in young children and treat them before it is too late. Blood samples are taken from children and sent to Kisumu, some hundred kilometres from Nairobi, where there is an adequately-equipped laboratory supported by the Centre of Disease Prevention and Control (CDC).

"This project has just started, but the initial results confirm our concerns," says Dr Thomas. "The first ten samples all turned out to be positive, as did the next ten, as did the ten after that. Having said that, these samples were selected because the cases were very suspect. Without such interference, we would see that less than 50% of children born of seropositive mothers are infected."

Even when a diagnosis is possible, another obstacle remains: the lack of ARV drugs designed specifically for children.

"Adults can now take triple therapy ARV drugs, allowing them to take the three medicines by swallowing one and the same tablet. These medicines are also less expensive since there are good quality generic versions available," explains Van Engelgem. "But for children, there are no such 'fixed-dose combination' drugs (FDCs).

"For example, we need one syrup containing all three drugs instead of three different syrups, as we use today. Certain medicines are available in syrup, but giving a precise dosage is difficult and children struggle with the horrible taste. Sometimes powder has to be diluted in water, but this requires finding clean drinking water.

"In slums like Kibera, this is hard. And then children grow and gain weight, which requires frequent changes in the required medication."

Precision in the dosage of treatment administered to children is essential. An inadequate intake could mean that the treatments fails and result in the virus becoming resistant to treatment.

On the other hand, over-dosing could produce side effects. Conscious of these problems, the MSF team has to break up adult tablets in order to ensure that the right quantity is given to child patients. Sometimes the pills are ground up to help the child swallow the medicine.

This approach produces results but requires close attention and expertise from the medical personnel. It is therefore difficult for the Minister of Health to reproduce such an approach on a large scale.

Group support sessions for child patients are very important. They help children understand their situation and exchange their experiences with others, which helps improve their adherence to treatment. Group sessions also offer an opportunity to tackles diverse subjects such as relationships between boys and girls or, for the teenagers, how to use condoms. Once a month children are grouped together by the MSF counselling team in Gatwekera clinic.

Mother-child health care, and especially ARV treatment for pregnant women, is a priority for the MSF team. The health centre in Kibera South and the Silanga dispensary both have sizeable mother-child care departments, which receive numerous patients each day.

"It is essential that the children know that someone is looking after them," explains Zaina Ahamed, a member of the team. "They eat a meal together, play games, participate in discussions and do drawing workshops. This way we give them time - time for them and not just for their mothers. We are alone with them, without their parents. They can say what they feel, ask their questions. We listen to them and respond to them. Without judging, without criticising. We are just there for them."

The importance of women

67% of patients currently registered in the MSF programme are women. In certain age groups, notably the 15-24 year olds, there are many more women than men affected by HIV/AIDS. In Kibera, the woman is often the principle breadwinner for the family as well as looking after the children. Women are key to the prevention of HIV/AIDS transmission to children and to ensuring that HIV positive children take their treatment correctly. They can also play an important role in encouraging their partners to take an HIV test.

But women are also first line victims of violence.

"In slums like Kibera, women are exposed to sexual and domestic violence," says Christine Jamet. "Violence towards women can prevent them from getting healthcare because they can't always move about alone."

Mother-child health care, and especially ARV treatment for pregnant women, is a priority for the MSF team. The health centre in Kibera South and the Silanga dispensary both have sizeable mother-child care departments, which receive numerous patients each day.

"It is largely a question of preventive care," notes Van Engelgem. "Pregnant women are encouraged to take an HIV/AIDS test. Those who are infected receive help to prevent the transmission of the virus from mother to child. MSF provides post-natal vaccination and a family planning service."