Active or prior GB virus C infection does not protect against vertical transmission of HIV in coinfected women from Tanzania.

To determine whether GB virus C (GBV-C) infection is associated with protection against vertical transmission of human immunodeficiency virus (HIV), we tested 186 HIV-positive pregnant women for GBV-C. Neither active nor prior GBV-C infection was associated with a lower rate of HIV acquisition among infants. Thus, GBV-C does not appear to protect against perinatal HIV acquisition.