An estimated 104 000 babies were saved from mother-to-child HIV infection in 2010.
The national HIV mother-to-child transmission rate (MTCT) dropped to 2.7% in 2011, according to a Medical Research Council report released on Thursday.
"This data shows a major achievement in the reduction off MTCT and we should celebrate it," Dr Ameena Goga of the Medical Research Counciltold reporters in Johannesburg.
This latest announcement should be seen a major development in South Africa's fight against HIV/Aids, the Medical Research Council said.
While not as dramatic as the drop from the 8% MTCT rate recorded in 2008 to the 3.5% rate of 2010, the 0.8% reduction the following year is still a significant achievement.
Goga said this indicated that an estimated 104 000 babies were saved from MTCT in 2010.
The decrease occurred in spite of a marginal increase in the percentage of infants exposed to the pandemic through their HIV-positive mothers from 32.6% in 2010 to 33.6% in 2011.