Of course it is not perfect, but it's about as good as using a condom.
Another way, which has been studied, is to use a drug called Tenofovir in a gel and as a lubricant. The amount of Tenofovir used was 1%. This seems to be about say 50% effective in people who used it religiously when having sex and about 28% in people who did not use it all the time. It is possible that a higher amount of Tenofovir, which is a pretty safe antiviral, might make this more effective but this has not been tested.
A tremendously important study (one among several) this one called iPrex showed that those who used Truvada every day and who did not have HIV were 97% less likely to get it than those who did not use Truvada. Unfortunately, if you look at everyone including people who did not take their pills all the time, the protection was 43%, which is good, but you can see how important taking the pills on time regularly is in having this method work.
When you put these ideas together with the existing ways we have taught people to protect themselves like condoms, safer sex practices like more oral less anal, serosorting, using clean needles, circumcision, fast at-home HIV tests, it is possible to imagine a world without HIV/AIDS.
This is because, using the work of the scientist Alice Blower who built models of how the epidemic would burn out if the transmission rate drops, it is clear that the ways mentioned above used together would bring that rate down far enough to end the epidemic. Eventually.
The better the methods are at dropping transmission the faster the epidemic will burn out and perhaps as important from a budget and social point of view, stop infecting new people.
But there are several studies that need to happen to make these methods even better than they are.
One is to see exactly how long after getting exposed to HIV you have to take a drug to protect you from getting HIV. Right now we say 30 days.
Another is to learn how far ahead of engaging in sex or drug use you have to take a drug to protect you from getting HIV. Is it a few hours, days, weeks or what?
Another is whether the type of drugs used (Truvada) might not be the best ones. What about the ccr5 drugs like Maravaroc. Or an integrase inhibitor like Issentress both of which in theory should protect a person from getting infected.
Another is whether a larger amount of drug for a smaller amount of time might work more effectively.
Some of these questions are being answered in two new big experiments going on, using Maravaroc and using drugs episodically.
But there are too few of the important questions being tested and there is another dilemma.
It is clear very few people know about PEP and PREP or how to get access to them, much less rapid HIV assays or how to use the new tools. And we do not have the money or mandate to educate the public in a systematic way.
It is also clear that most of the world is unable to even get drugs to treat HIV for those who are quite sick, much less getting enough money to make PEP and PREP realistic for the tens of millions who will otherwise be infected over the next few years.
To get these methods used, we need political will—a decision to put an end to AIDS, from a group of rich countries that would not even pay for the drugs they promised to give the poor countries—the 11th installment of the Global AIDS Fund was postponed this year causing great harm to many countries.
We need a political movement because right now, ending AIDS is not a medical or scientific issue—we know HOW to do it. It is a political issue—we need to get the money, the will TO do it.
It took no time at all for the USA to spend 1 trillion dollars to get rid of Saddam Hussein. But to get rid of a real enemy, HIV, the USA is having a hard time getting the support for spending a few billion dollars, a thousandth of what was spent protecting no one who lives here or in Africa or Asia from anyone capable of hurting them while ignoring a disease that has killed some 40 million people and right now has infected about another 40 million people.
We need to get our priorities straightened out.
Or we will be teaching about HIV for the next thousand years and never getting rid of it, which we have done for smallpox and almost finished doing for polio.
It's time to act.