People with HIV who start treatment before their CD4 T-cell count falls below 800 have a substantially smaller viral reservoir, which could improve their prospects for long-term remission. Although antiretroviral therapy can keep HIV replication under control while treatment continues, the virus inserts its genetic blueprints into human cells and establishes a long-lasting reservoir, making it difficult to eradicate. Researchers assessed the association between CD4 count at the time of treatment initiation and HIV persistence in 149 participants in the START trial, which showed that early treatment leads to better outcomes. They were divided into three groups based on their CD4 count at treatment initiation: 500 to 599, 600 to 799 or 800 and up. After three to four years on anti-retrovirals, total HIV DNA, plasma HIV RNA and HLA-DR expression (a measure of T-cell activation) were significantly lower in people who started treatment with a CD4 count of at least 800. What’s more, these measures were significantly lower in women compared with men.