At least 35 million people around the planet live with HIV, and it kills over 1.7 million people each year, so the fact that it’s currently untreatable is one of the biggest medical problems of our time. But in recent years scientific advances seem to be kicking HIV's arse more effectively than ever — so is there hope that we neutralise the virus's threat? The answer is more hopeful than you think.
It's a big ask though. You can’t treat HIV easily. It evolves so quickly that any drug you use suffers drug resistance extremely quickly. Instead, you have to work with exotic treatments for patients with longstanding HIV, or try and wipe it out before it’s had chance to act.
With so many existing sufferers, an effective cure for existing HIV patients is of huge importance — but it needs to be safe and repeatable. If we want to eradicate the disease entirely, then it's essential that HIV can either be prevented or treated at the earliest possible stage in order to limit its spread. And in order to achieve that kind of scope, whatever treatment we use needs needs to be cost-effective and reliable.
Even then, we'd still require a widespread shift in policy and thinking to turn solid research into a practical solution. If history is any guide, turning a scientist's findings into social and political practice is never as easy as we'd hope. So where, right now, do we stand?
Truth is, we've already done it. Back in 2007 Timothy Ray Brown, a 40-year-old HIV-positive patient, was given stem cell treatment for acute myeloid leukaemia. Brown was on the brink of death, and the stem cells were a final hope. And the cells he received were from a donor with a rare genetic mutation which confers resistance to HIV infection. Over the course of 20 months following the procedure without antiretroviral drugs, the levels of HIV in Brown's blood, bone marrow and bowel became undetectable. A report in 2011 confirmed that he had not relapsed. He had, and still has, beaten HIV.
Brown's case was highly specialised, and it can't be stressed enough that the cure almost killed him. Just last week, however, two more patients were freed from HIV drugs thanks to bone marrow transplants. The two men — one of whom became infected with HIV "in the early years of the epidemic," the other as a baby — were given bone marrow transplants to treat cancers of the blood. Since, the level of HIV virus present in their bloodstreams has dropped and become undetectable. The men have since stopped taking antiretroviral medication — and there's been no sign of the virus returning.
So job done, right? Well, not quite. That’s still only three patients that seem to have been cured of longstanding HIV. That’s three more than anyone expected a decade ago, sure, but while stem cell and bone marrow transplants may prove effective, they aren’t necessarily practical. There's a 15-20 per cent mortality rate tied to marrow transplants, and even then the drugs used to suppress immune reaction against the donor cells can cause problems for patients — especially those with HIV.
Finding a cure that can effectively free a person from HIV is tough. It's not just a case of wiping out the virus — through whatever means you can — but also causing as little collateral damage as possible. After all, the immune system of an HIV sufferer is already on its knees, so the last things it needs is an onslaught which will makes things worse, and that’s never more the case than when a patient has had the virus for an extended period. What’s really required is effective early-stage treatment.
Catch It While You Can
Fortunately, there’s no shortage of work in that area, either. The thinking is common sensical: If trying to shake the virus when it’s established is risky, all the better to stamp it out early. So medics have been testing whether it’s possible to throw drugs at the disease in its very early stages, hopefully crippling the virus before it can have its wicked way on the immune system.
It might sound like a crude idea, but there are results which suggest it could be effective. Earlier this year, a child of an HIV-positive woman was treated with antiretroviral drugs just 30 hours after its birth. While the process was a long and slow one — with the infant testing positive for HIV on five separate occasions — the child has now, at age two and a half, been taken off drugs for an entire year and shows no signs of the virus.
In another trial, 14 patients were given antiretroviral medication between 35 days and 10 weeks of contracting the virus. While they stayed on the drugs for an average of three years, they all eventually came off the pharmaceuticals. They have also been deemed to be free from the virus.
Elsewhere, there are other routes to taking on the disease through drugs alone. Instead of brute force, they rely on finding a chink in the virus’s armour. And with researchers throwing the weight of supercomputers at unlocking HIV's secrets, we may not have long to wait before a serious breakthrough.
Just recently, a team from the University of Illinois worked out how HIV’s capsid — the casing which protects the virus from the body’s immune system — is built up from from proteins. Capsids lie between the virus's spherical outer coat, a 0.1 micron-diameter, lipid-based layer known as the viral envelope, and a bullet-shaped inner coat known as the viral core that contains the strands of HIV RNA. The things comprise 2,000 copies of the viral protein, p24, arranged in a lattice structure, and are responsible for protecting the RNA load, disabling the host's immune system, and delivering the RNA into new cells. In other words: It's HIV's evil mastermind.
But by feeding in electron microscopy data collected in lab experiments to a $US108 million, 11.5 petaflop supercomputer, the researchers used 49,000 AMD CPUs to work out exactly how the capsid is made up — and, crucially, how it works. Armed with that knowledge, scientists can start trying to work out how best to attack HIV at the molecular level. Just give them a little time.
Ounces of Prevention
There is, of course, another way. In an ideal world, we’d have a vaccine for HIV, just like we do for measles, tuberculosis and all manner of other diseases. In many ways it’s the cure that matters most. Vaccinate the young and, in a couple of generations time, the virus could be a thing of the past, like polio or smallpox. No surprise, then, that people are keen to find an HIV vaccine that works. And they're making remarkable progress.
Last year, the FDA approved the first-ever preventative drug for HIV. Called Truvada, it’s what’s known as a pre-exposure prophylaxis, a prevention method that has people who don’t have HIV take a daily pill to reduce their risk of becoming infected. So far, it seems to be working. It’s been shown to reduce the risk of HIV infection by 42 per cent compared with placebo in a population of 2499 patients involved in “high risk” sexual activities, while another trial in 2400 Thai drug addicts saw a staggering 74 per cent reduction. They’re frankly amazing numbers.
The only problem is that it’s a daily dose. That means it's inconvenient, susceptible to being forgotten and, sadly, expensive. If it can be turned into a vaccine, where one shot provides a similar level of protection, we’d really be talking. But, at the time of writing, such a development remains a far-off fantasy.
The Long Home Stretch
So, we've cured three people of HIV, are getting pretty good at heading it off at the pass, and are throwing the weight of supercomputing and vaccinology at the problem. We're beating down the door. Here come the caveats.
HIV is a tricksy little virus, and it’s well known that it's able to lay dormant in the body at low levels — and only later become active. So when you read a headline that proudly claims a patient to be cured of HIV, in reality it means that the level of HIV in their system has dropped below a detectable level. That’s still a wonderful thing, but it does mean that, with all of these treatments and preventions, people could still be carrying the virus — and it could at any time rear its head more seriously or even be transmitted. Sadly, there’s little that can be done about that, and for now we’ll have to comfort ourselves with it being as close to a cure as we can get.
But there’s a bigger problem in stamping just HIV than caveats of medical science — and that’s boring old logistics. When you’re trying to eradicate a disease that affects 35 million people, you need coordination — and that means broad social and political agreement, which isn’t easy to come by in many of the nations that need it the most.
But the good news is that World Health organisation, the driving force many a global health initiative, has recently proposed a vast scale-up in HIV treatment that looks like it could really gain traction. Currently, the WHO recommends that HIV treatment shouldn’t begin until each cubic millimetre of a patient's blood contains fewer than 350 of the white blood cells targeted and destroyed by HIV. But its new proposal is to push that cut-off up to 500. around the globe — slashing the likelihood of disease progression by 50 per cent and dramatically increasing the number of people that receive treatment at an early stage.
It's undeniably one of the most positive policy steps for HIV in recent history. Combine that kind of social thinking with the amazing scientific research that's being undertaken — three people cured, dozens with HIV abated, and the world's weightiest computing power crunching the associated numbers — and it's impossible not to be hopeful. One day, soon, HIV will be dim and distant memory.