December 7, 2021

I, Science

The science magazine of Imperial College

HIV test blood samplesLast week the world rejoiced as the papers announced: ‘HIV is cured!’. Except of course it isn’t – or at least not yet.

The hype is somewhat justified: for the first time, scientists have developed a new drug that could, in theory, completely clear the virus from a patient. HIV tends to ‘hide’ inactive cells of the immune system, which protects it from attack. This drug modifies these cells to ‘wake them up’. If they are then infected with HIV, it will begin to replicate, marking those cells as infected. This allows your natural defences to find and kill the infected cells in your body, wiping out the reservoir of hidden virus that would otherwise allow the disease to return. Consider yourself ‘cured’.

So far so good, but let’s take a look at the problems of this recent study: involved patients were already on a highly effective antiviral treatment programme, which reduces the concentration of HIV virus particles in your blood to such a low level, that tests cannot detect it. Thus reporting that these same patients have no HIV particles in their blood after this new treatment is meaningless. Inactive infected cells could reactivate at any time and seed a new infection. The only way to truly test if these patients are cured is to take them off their antiviral treatment and see if the virus comes back.

Looking back in history

This isn’t the first time that we’ve ‘found a cure’ to HIV. In 2010, a child born to an HIV positive mother was thought to have been cured through intense antiviral therapy immediately after birth. Just when the possibility that new-borns could be cured of HIV was being investigated, the virus returned to the child four years later. This highlights the endurance of HIV infections.

In fact, despite many headlines over the years, only one person has ever been officially cured of HIV. In 2007 Mr Brown, who had lived with the virus for eleven years, had his immune system completely destroyed – taking the inactive infected cells with it – and replaced with a new one through a bone marrow transplant from a donor who was naturally resistant to HIV infection. To date he remains HIV-clear, although there is still no guarantee that the virus will not return.

HIV is excellent at hide-and-seek, and so far it’s winning the game. This new approach of ‘waking up’ inactive infected cells could be the first step on the road to a cure. But be warned – so far we know nothing about whether this treatment will make any difference in humans, and it may be a long time before that question is answered.

Aran Shaunak is studying for an MSc in Science Communication.

Image: HIV, ktsdesign