Rapid drug treatment of babies with HIV dramatically cuts their risk of death and debilitating disease, international research shows.
The study prompted the World Health Organization to change its guidelines, which had recommended delaying therapy until symptoms became apparent.
It found giving antiretroviral therapy (ART) straight after diagnosis cut the risk of death from Aids by 76%.
The study appears in the New England Journal of Medicine.
The study, of 377 HIV-positive South African babies, found that babies given treatment immediately after they were diagnosed with HIV cut their risk of dying from the infection to just 4%.
In comparison, the risk of death for those whose treatment was delayed until their levels of key immune system CD4 cells began to fall, or other symptoms emerged, was 16%.
Immediate treatment also cut the chance of disease progressing measurably by 75%, from 26% to 6%.
The findings were so conclusive that treatment for all babies was re-assessed at the preliminary stage of the trial.