Many posted already about the incipience of HIV/AIDS occurrence in USSR, but most noticebly the spread of the disease drastically increased post-Soviet, form 1990-1993 the HIV incidence doubled (maybe even more given the undermining bias of Soviet-era officials) not because of migration but injectible drug-use (IDU).

So while the "Iron Curtain" anti-migration posture did little to prevent AIDS from entering the USSR, repressive drug policies held by the Soviet state, along with forced societal stability (even in its decline), may have curtailed the spread of HIV/AIDS through IDU.

Tl;DR Iron curtain did little, but overall Soviet anti-drug repression did prevent the spread of the disease through IDU's.

No. HIV was first found in the USSR in 1985 amongst foreign students. In 1987 a former embassy worker was discovered to be infected and by the end of that year there were 25 identified cases amongst the citizens of the USSR.

source: Russian AIDS centre

This question is inherently difficult to answer for one reason: it is very difficult to ascertain HIV infection rates anywhere in the world including countries where HIV stigma is not as significant as it is in a place like Russia where foreign nationals with HIV are still being deported. There are three factors to consider:

1. In order to diagnose HIV, the patient must submit to an HIV test. Whether or not an HIV test will even be offered depends upon a complex equation of factors including the awareness of HIV-related symptoms on the part of the medical provider, the availability of testing technology, whether the patient is able and willing to seek diagnosis, and whether or not the medical provider decides that the patient is part of an "at risk" group.
2. Symptoms of HIV/AIDS are difficult to detect until the very late stages of the illness. Often, in the 1980s, a patient was diagnosed with AIDS after developing Kaposi's Sarcoma, a rare form of cancer. But the truth is that because HIV suppresses the immune system, a person infected with the virus could develop any kind of what are called opportunistic infections which run the gamut from really any kind of cancer to pneumocystis pneumonia to various fungal infections. If the patient presented the symptoms of brain cancer, for example, then the patient would likely be diagnosed with brain cancer and any further diagnosis would not be pursued.
3. If a Soviet patient even got to the point of diagnosis, one still can not underestimate the significance of stigma in reporting the infection. I find it interesting that, in this thread, others have reported that HIV was first detected in the Soviet Union in foreign nationals. No matter where HIV diagnoses occur, there is often a deliberate attempt on the part of the government to portray the disease as if it were solely being transmitted by depraved foreigners. Given the amount of xenophobia and homophobia that we are continuing to see in contemporary Russia, I do not doubt that the Soviet Union had a vested interest in portraying itself as immune to the kinds of activities which spread HIV in the West. Sexually Transmitted Infections (STIs) are not like other diseases. Social mores dictate how these diseases are diagnosed, treated, and reported. Sadly, I don't know of a historian who has yet explored the history of HIV/AIDS as a social phenomenon, but you can check out No Magic Bullet: A Social History of Venereal Disease in the United States Since 1880 if you are interested in exploring the ways in which social mores can affect the development of infrastructures which diagnose, treat, and report STIs.

Given these factors, I believe it is impossible to know whether the politics of the Soviet Union hindered the spread of HIV. Going back and diagnosing patients who were diagnosed incorrectly or incompletely or whose diagnoses were not reported at all is a nearly impossible task for the historian. Accurate history reporting depends upon accurate documentary evidence, and if the evidence isn't there, it just isn't there.

edit: spelling

Also in the early 90s there was a huge surge in HIV in children in Romanian children homes from tainted blood, blood products and reused medical equipment. Much of the story was ignored till Romania started selling blood products to western countries and they found much higher than normal HIV rates. We still dont know how many died from Aids due to the chaos in that country in that time.

ALMOST THERE!

No doubt there was an intense Russian influence, you could even argue the Russians were directly responsible for contributing to the culture that caused the AIDS outbreak in the first place. But no one here has hit on that, likely because they don't know about it.

In the late 1960, and 1970s, the Russians began testing biological weapons in rural villages in Korea and Africa. The Russians were attempting to weaponize, or at least understand the weapon capabilities, of hemmrogatic fever viruses - Ebola, Marburg, Haunta.

The prospect of a weapon being created that could lead to a mass extinction event, unintentionally, was a mighty sobering concept for America.

Now its unclear how much was intentional, how much was military leadership capitalizing on an opportunity, and how much was pure accident.... but what HIV evolved into was a very very important lesson about the folly of getting "creative" and intentionally hybridizing pathogens. You could accidentally kill the species. And as such, that's exactly what happened in America.

Research the professional history of all the major founding scientists of the HIV mythos.... you will find almost all of them were involved with various biological weapons research in the 1970s.

HIV didn't spread to the region because it wasn't publicized in the region. I think in all likelihood, they thought the AIDS outbreak was a biological weapons test. The ultimate trump card to win the cold war.

HIV today, isn't what it was. Functionally, HIV is a world wide mythology that persuades the most sexually active people from around the world, particularly in regions where Russian biological weapons were tested, to submit regular blood samples - that are eventually indexed by their immunological profiles by a central repository at Los Alamos National Laboratory. In effect, HIV has become the watchdog for biological weapon deployment - intentional or unintentional. It has become the defense against the irresponsible behavior Russian scientists exhibited when deploying bioweapons to people.