This study aimed to estimate HIV incidence in the United States using new assays that can differentiate recent from long-standing infections. The researchers analyzed remnant serum specimens from 22 states where HIV diagnoses were made in 2006, testing them with the BED HIV-1 Capture Enzyme Immunoassay to classify infections as recent or long-standing. They estimated that 56,300 new HIV infections occurred in the U.S. in 2006, with an incidence rate of 22.8 per 100,000 population. The majority of infections (53%) were among men who have sex with men (MSM), and 45% were among blacks. The study also used an extended back-calculation model to estimate HIV incidence from 1977 to 2006, showing that incidence peaked in the mid-1990s and has been stable since. The findings highlight the continued concentration of HIV infections among MSM and African Americans, emphasizing the need for targeted prevention efforts.This study aimed to estimate HIV incidence in the United States using new assays that can differentiate recent from long-standing infections. The researchers analyzed remnant serum specimens from 22 states where HIV diagnoses were made in 2006, testing them with the BED HIV-1 Capture Enzyme Immunoassay to classify infections as recent or long-standing. They estimated that 56,300 new HIV infections occurred in the U.S. in 2006, with an incidence rate of 22.8 per 100,000 population. The majority of infections (53%) were among men who have sex with men (MSM), and 45% were among blacks. The study also used an extended back-calculation model to estimate HIV incidence from 1977 to 2006, showing that incidence peaked in the mid-1990s and has been stable since. The findings highlight the continued concentration of HIV infections among MSM and African Americans, emphasizing the need for targeted prevention efforts.