The child was born to an HIV infected mother and was started on aggressive ART 30 hours after her birth. After 29 days there was no detectable virus. Treatment was continued until she was 18 months old and then the treatment was discontinued. 10 months later the child remains free of the virus.
The theory is that by starting treatment so early the medication kept the hard to treat viral reservoirs from forming. Viral reservoirs is basically why people with HIV have to stay on treatment lifelong. The medication they take suppresses the virus to undetectable levels, but as soon as they stop the virus starts reproducing in these viral reservoirs and levels of the virus rise again.
Recent research has shown that these reservoirs develop within a few weeks of infection, therefore there seems to be a small window during which infants can be treated and remission may be achieved
A new study will begin next year that will test this theory in more infants.