Epidemiology

MTCT-Plus site in Uganda.
Photo: Gideon Mendel

At the 17th Conference on Retroviruses and Opportunistic Infections, held in San Francisco in February, Dr. Elaine Abrams, professor of Epidemiology at the Mailman School and professor of Pediatrics at the College of Physicians and Surgeons, warned that the rate of new pediatric HIV infections continues to remain high in the developing world. The presentation reviewed findings from recent studies that aimed to optimize treatment strategies to prevent mother-to-child transmission (MTCT) and to optimize the treatment of infants and children who acquire HIV infection.

Dr. Abrams is the senior director for research at the International Center for AIDS Care and Treatment Programs (ICAP) and the director of the MTCT-Plus Initiative, a multicountry care and treatment program for HIV-infected women and their families  in nine countries in Sub-Saharan Africa and Thailand.  Dr. Abrams has also been  responsible for pediatric and mother-to-child prevention activities  implemented in ICAP-supported programs in Africa.

To get a sense of scale of the epidemic, Dr. Abram noted that in 2008 there were an estimated 430,000 new pediatric infections worldwide (about 1200 children per day), primarily attributable to MTCT. In sub-Saharan Africa alone there are an estimated 1.8 million children living with HIV infection.

Slow movement in implementing new perinatal prevention measures has  played the primary  role in the increased number of infections.  However, an increasing number of those HIV infected children represent prevention failures, becoming infected due to limited effectiveness of the antiretroviral prophylaxis regimen used. 

In most high-prevalence HIV settings, single-dose nevirapine alone or in combination with zidovudine comprises the predominant prevention intervention.  However, use of single-dose nevirapine to prevent MTCT selects drug-resistant viral mutations among a large proportion of children who fail prophylaxis; compromising outcomes of nevirapine-based therapeutic treatment regimens when used in these infants.

Recent studies have looked at ways of improving treatment strategies for nevirapine-exposed children with protease inhibitor-based therapy now recommended for infants and young children with prior nevirapine exposure.

Dr. Abrams also discussed the particular challenges of early treatment for HIV-infected infants given that lifelong treatment options are severely compromised by drug resistance, a limited pediatric formulary, and the complexity of therapy as a child grows and develops.

An article on Pediatric Supersite provides further details on Dr. Abrams presentation.