If you look at the transmission statistics for several Asian countries, it will say “heterosexual” is the main form of transmission. Laos, Thailand and Vietnam included.
Anyways, several of my friends from Southeast Asia say they barebacked prostitutes several years ago (10+ years ago) and nothing happened to them, and now they have families (a wife and kids) and they are showing no health problems. Not that I advocate barebacking whores because it seems risky (even if you don’t get HIV, you can still get some other nasty disease or infection), but they were lucky.
Well in Thailand the disease there probably started originally with IV drug users, and that still drives a great deal of it. IV drug users give it to each other, and then those men take it home and give it to their wives. That is what is driving the epidemic in Southern Thailand on the peninsula around the Phuket region.
Then a lot of it was going due to transmission from whores to their clients. This was mostly the Thai whores were serving Thai men, and that scene is a lot sleazier that the more high class ones that serve Westerners. The ones that serve Thais were working in brothels where they had to serve many men a day, and after a while, they did not even get turned on anymore, so they were getting fucked dry. This can cause some bleeding, so these whores were bleeding when they were having sex. The bleeding was spreading it heterosexually to the Thai men.
However, some Thai whores who were serving Westerners were also HIV positive, and there was some transmission taking place to the Western customers. There are reports, though not common, of Western men barebacking Thai whores only one time and getting HIV.
But an information campaign got a lot of those whores to use condoms and now the rate of female -> male HIV in those brothels is very low to none.
I have no idea what is driving the spread of HIV in Laos and Vietnam, but Thailand had a serious HIV problem at one time at least.
In addition, that particular subtype of HIV does seem to spread easier female -> male. They even proved this scientifically when they tested HIV positive women who had this subtype. Titers were significantly higher in vaginal fluid in these Thai women then they are in US HIV positive women who have the subtype B clade. The subtype B clade for whatever reason seems to mostly want to spread via blood. Titers in vaginal fluid of women with the B clade are so low that I wonder how they can even transmit the illness.
There are other subtypes in parts of the world outside of the US and Europe. Some of these are in places where there seems to be is more HIV spread by heterosexual contact than in the US, where it mostly goes:
HIV drug user male -> other male HIV drug user -> woman -> transmission stops.
For whatever reason, almost all HIV in the US has always been clade B since the start of the epidemic. The other subtypes have just not made it over here yet in any real numbers, though there are some non-B clades in Europe.