Tremendous progress has been made over the past few years in diagnosing and treating infants and children with human immunodeficiency virus (HIV) infection. However, much remains to be done to effectively scale-up and sustain prevention efforts and treatment services for all in need. The most efficient and cost-effective way to tackle paediatric HIV globally is to reduce mother-to-child transmission (MTCT). In 2008, an estimated 45% of pregnant women living with HIV received antiretrovirals (ARVs) to prevent transmission of HIV to their children. However, every day, there are nearly 1 200 new infections in children less than 15 years of age, more than 90% of them occurring in the developing world and most being the result of transmission from mother to child.

HIV-infected infants frequently present with clinical symptoms in the first year of life. Without effective treatment, an estimated one third of infected infants will have died by one year of age, and about half will have died by two years of age. While progress has been made in preventing new HIV infections in infants and children, greater efforts are needed to scale-up these effective preventive interventions as well as services for care and treatment.

The 2009 progress report Towards universal access: scaling up priority HIV/AIDS interventions in the health sector, documents the progress made by countries in scaling up antiretroviral therapy (ART) for children. In 2008, over 275 000 children received ART, up from 127 000 in 2006. This is 38% of those in need using the previous 2006 recommendations for ART initiation in children. Given the new guidance contained in this document, estimates of the numbers of infants and children who qualify for ART will have to be revised.

HIV-infected infants and children now survive to adolescence and adulthood, and the challenges of providing HIV care are evolving into the challenges of providing both acute and chronic, lifelong care. Despite the high risk of early mortality in HIV-infected infants and children, the average age at initiation of therapy in children in resource-limited settings remains high.

Significant obstacles remain to scaling up paediatric care, including limited screening for HIV, a lack of affordable, simple diagnostic testing technologies for children less than 18 months of age, a lack of human resources with the capacity to provide the care that is required, insufficient advocacy and understanding that ART is efficacious in children, limited experience with simplified, standardized treatment guidelines, and limited availability of affordable and practical paediatric ARV formulations. Health-care systems remain unable to meet the demands of national paediatric ART coverage. Consequently, far too few children have been started on ART in resource-limited settings. Moreover, the need to treat an increasing number of HIV-infected children highlights the primary importance of preventing transmission of the virus from mother to child in the first place.

The WHO guidelines Antiretroviral therapy for HIV infection in infants and children are based on a public health approach to HIV care. Updated in 2010, these guidelines are harmonized with the treatment guidelines adopted for adults, pregnant women, and for prevention of mother- to- child transmission (PMTCT).

The present guidelines are part of WHO’s commitment to achieve universal access to the prevention, care and treatment of HIV infection in infants and children.