Relative replication fitness of a high-level 3'-azido-3'-deoxythymidine-resistant variant of human immunodeficiency virus type 1 possessing an amino acid deletion at codon 67 and a novel substitution (Thr-->Gly) at codon 69
Laboratory of Molecular Retrovirology, Clinical Services Program, SAIC-Frederick, Frederick Cancer Research and Development Center, Frederick, Maryland 21702, USA. timamichi@nih.gov