| MadSci Network: Virology |
There is almost no chance that HIV will ever change its mode of transmission. Almost all retroviruses are spread very slowly by direct intimate contact, or by mother to infant transmission in the womb or during birth and breastfeeding.
The more relevant question is about other viruses, that are easily transmissible, becoming more harmful to humans. This happened with the 1918 influenza A virus for example.
Try the links in the MadSci Library for more information on Virology.