Transmission from one child to another of human immunodeficiency virus type 1 with a zidovudine-resistance mutation

BACKGROUND AND METHODS. We describe a child who apparently acquired human immunodeficiency virus type 1 (HIV-1) infection in the home setting. The suspected source of infection was a child with the acquired immunodeficiency syndrome who had received zidovudine and whose virus contained a mutation associated with in vitro zidovudine resistance. The children were born to different HIV-1-infected mothers, but they lived in the same home between the ages of two and five years. Child 1 was infected perinatally; Child 2 was not and was repeatedly found to be seronegative. Child 2 was examined because of acute lymphadenopathy and had seroconverted to HIV-1 positivity. HIV-1 proviral DNA was amplified from peripheral-blood mononuclear cells and subjected to sequence analysis. Sequences from Child 2 were compared with those from Child 2's mother, Child 1, and local HIV-1-infected control children.