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Treatments in children
   Last updated: 21.12.05
 
Despite advances in the prevention of mother-to-child HIV transmission, children continue to be born with HIV infection. 95% of HIV-infected infants are identified via blood tests called HIV PCR by one month of age. An HIV PCR-negative result will not be confirmed until the baby is 3-6 months old and has negative results on two or three separate PCR tests. Paediatricians usually want to check that HIV antibody from the mother has disappeared with a final blood test at 12-18 months.

Babies may be given anti-HIV therapy such as AZT or nevirapine for up to six weeks after birth. This treatment aims to prevent mother-to-baby transmission.

Immune system in children
CD4 cells are the immune system cells that HIV infects and destroys, and the CD4 count roughly reflects the state of the immune system. Healthy children normally have higher CD4 counts than adults. In adults, a CD4 count below about 250-350 means that you are at risk of becoming ill. In children over about 5-6 years of age, the same applies, but in younger, uninfected children CD4 counts are much higher and also more variable. Very young children can become sick even though the CD4 count is as high as 1000-2000.

The CD4 percentage is also used to assess a child’s immune system. This measures the number of CD4 cells as a proportion of all immune system cells. If a child’s CD4 percentage is below 25%, there is some immune damage. Severe damage is indicated by levels below 15%, and the risk of illness is even greater.

Viral load in babies and children
Viral load is normally very high (e.g. 200,000 copies/ml) in the first year of life. However, this doesn’t necessarily mean that the child will get sick. Viral load slowly declines in children between the ages of one and five years. Before attributing a fall in viral load to the effect of anti-HIV treatment, this natural drop (of about 0.6 log per year) should be considered.

Treatment of babies
Guidance on the timing and use of anti-HIV treatment in babies and children varies. Some doctors believe treatment should begin as soon as HIV infection is confirmed. Others favour delaying treatment – partly through concerns about the demands which today’s drug combinations place on young children and their carers – and monitoring closely.

The usual childhood vaccines are safely given to HIV-infected babies and children. Septrin (co-trimoxazole) to prevent PCP, a common AIDS pneumonia, is recommended when the baby is about one month old. Treatment continues until the baby is confirmed HIV-negative, or until the child is one year of age and tests indicate little damage to his or her immune system. PCP prophylaxis may continue even if the CD4 count is okay as it helps to prevent other ear and chest infections which are more common in children with HIV.

Treatment of children
Anti-HIV therapy is often recommended if a child has a low and falling CD4 count and CD4 percentage for his or her age group; a high or increasing viral load; or has symptoms. Treatment with anti-HIV drugs is often not as effective at reducing the HIV viral load in a child’s blood as it is in adults. This is probably because viral load is often very high in children. For example, triple combination therapy, which often reduces viral loads to below 500 copies in most adults, may only achieve this result in about 40% of children.

There is some evidence that four drug combinations are more likely to reduce viral load to undetectable levels in children. Nevertheless, getting children to take syrups and pills regularly may be very difficult. This is likely to make treatment ineffective and may allow drug resistance to develop.

Treatment options
The nucleoside analogues AZT, d4T, 3TC, ddI, and abacavir are available for the treatment of children aged three months and over, and FTC is available for children aged four months and over. The protease inhibitors lopinavir/ritonavir and ritonavir are available for children aged two and over, nelfinavir can be used in children aged three and over, and amprenavir and indinavir can be given to children aged over four. The NNRTI nevirapine is also available in liquid formulation for children aged over two months and efavirenz to children who are three or older or weigh over 10kg.