Blood tests in late 2015 revealed the child is in HIV remission, meaning levels of the virus in the blood are undetectable using standard tests.
"This is really very rare," said Dr. Avy Violari, head of pediatric clinical trials at the Perinatal HIV Research Unit at the University of Witwatersrand in South Africa.
"By studying these cases, we hope we will understand how one can stop (treatment),"
In infants infected with HIV close to birth, progression of the disease occurs very rapidly within the first few months of life and can often lead to death, according to the World Health Organization. An estimated 110,000 children died of AIDS-related illnesses in 2015, according to UNAIDS.
The study found mortality decreased by 76% and HIV disease progression reduced by 75% among the infants who received treatment immediately, for 40 or 96 weeks.