Advances in Pediatric HIV Research
Despite the recent advancements in perinatal transmission research, the HIV/AIDS epidemic in children is hardly over. Even the most optimistic experts in the field acknowledge that, because women are among the fastest groups of people becoming infected with HIV, trends in perinatal transmission rates are likely to increase once again over time. It is estimated that more than 20,000 children in the United States are infected with HIV. While these children can expect to live longer, healthier lives in the age of highly active antiretroviral therapy (HAART), their treatment options are fewer and much less understood than those available for adults.
Over the past few years, there have been important advances in the diagnosis of HIV infection in children and infants. Until recently, it was difficult to confirm a potentially-
There has also been much progress made in understanding the natural course of HIV disease in children. HIV-infected children differ from HIV-infected adults in numerous ways. For starters, there is a much more rapid rate of disease progression in children; the average time to an AIDS diagnosis is 8 to 17 months in children, compared to 8 to 11 years in adults. Secondly, normal T-cell counts are significantly higher in children younger than 6 years of age and can fluctuate greatly. Thus, it is much harder to determine when opportunistic infections (OIs) might occur in HIV-infected children and to determine whether or not antiviral treatment or combinations of treatments are yielding the desired effect. Thirdly, HIV-infected children -- possibly due to their high T-cell counts -- have higher viral load levels than those typically seen in adults during the first several years of infection. Finally, HIV-infected children have an increased incidence of recurrent invasive bacterial infections. Moreover, OIs often represent primary disease with a more aggressive course, given lack of prior immunity. For example, an HIV positive child who has never been infected with the chicken pox virus may develop a severe case of chicken pox with initial (primary) infection. In contrast, many OIs in adults are reactivations of latent infections to which some level of immunity may exist. The chicken pox virus, which remains dormant inside of the body after the primary infection, may reactivate in an HIV positive adult or a child who has already had chicken pox, as shingles.
The number of treatments available to children has grown considerably over the last few years. The theory behind treating HIV-positive children is very similar to that of adults with HIV: HAART should be initiated promptly to slow HIV replication and disease progression. Yet, only a percentage of the total number of treatments approved for adults can be given to children, due to lack of pediatric safety data and formulation problems. Although some treatments are available in either a liquid or powder formulation for children, many other drugs are only available in adult-
The antiviral treatments available in pediatric formulations include: AZT, ddI, d4T, 3TC, ritonavir, and nelfinavir. Glaxo-
Tim Horn is a member of the Pediatric AIDS Clinical Trial Group's Community Constituency Group.