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Updated: Feb 26, 2026

Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
Published on: September 26, 2011
HIV-1 subtype diversity trends in a Northern California cohort
Kaiming Tao1, Philip L Tzou1, Malaya K Sahoo2
1Department of Medicine, Division of Infectious Diseases, Stanford University, Stanford.
Abstract:
Between 2000 and 2019, the Stanford Healthcare Clinical Virology Laboratory performed HIV-1 resistance testing for 9199 individuals in Northern California. Nonsubtype B viruses were identified in 3.5%, most often CRF01_AE (1.0%), subtype C (1.0%), CRF02_AG (0.46%), and subtype A (0.45%). Non-B viruses, particularly CRF01_AE and CRF02_AG, increased significantly over time. Although subtype B remained dominant, the rising presence of non-B subtypes reflects growing viral diversity within the U.S. epidemic.
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