Varicella (chickenpox) results from primary infection with VZV. Varicella, a common and usually benign illness in normal children, is more severe in HIV-infected children and may result in other conditions such as HZ (shingles). HZ is due to reactivation of latent VZV acquired during varicella and is common in HIV-infected children who have had natural varicella. While HZ is not likely to be life-threatening in these children, it does cause considerable morbidity and interferes with quality of life. Use of a live-attenuated VZV vaccine may be able to boost immunity in these children.