The prevalence of HIV among children admitted to one of South Africa's largest hospitals dropped from 31.9 percent in 2005 to a still-high rate of 19.3 percent in 2010, aidsmap reports. Pediatric HIV death rates have decreased by half during that time, from 24 percent to 12.3 percent. Researchers attribute these improvements to reduced rates of mother-to-child transmission and the introduction of antiretrovirals (ARVs) to South Africa, which now has the largest ARV program in the world. But childhood HIV remains a problem; in 2009, South Africa had an estimated 330,000 HIV-positive children—13 percent of all such children worldwide—and one-third of all deaths among children ages 5 and younger were attributed to HIV. Since the Chris Hani Baragwanath Hospital, the site of the research studies, is a well-staffed hospital in a relatively wealthy urban area, the results of the study do not apply to poorer and more rural regions of the country.