Read about the progression of the HIV virus in the body and how CD4 cell counts and the measurement of viral load indicate prognosis.
Dr Sindisiwe van Zyl qualified at the University of Pretoria before working for an HIV/AIDS NPO in Soweto for many years. She was named one of the Mail & Guardian's Top 200 Young South Africans in 2012.
Questions posted to HIV/Aids expert
questions answered by the expert