In 2010, a woman who had received no pre-natal care arrived at a hospital in rural Mississippi already in labour. Tests revealed she was HIV (human immunodeficiency virus) positive. She gave birth to her baby girl before medication could be given which may have prevented the transmission of the virus from her to her baby.

If a mother is known to carry HIV, medication during pregnancy can reduce the risk of transmission from up to 45% down to less than 2%.

Melbourne hosts the 20th International AIDS Conference this week. Image credit: Scott Cresswell via Flickr

Positive

They tested the baby for HIV at 30 and 31 hours of age and the results came back positive; the baby had HIV. From 30 hours of age, the baby was put on an aggressive treatment regime.

Tests at six, 11 and 19 days all came back HIV positive too.

But at 29 days of age, levels of HIV in the baby were suddenly so low that the virus could no longer be detected by standard tests. The baby wasn’t breastfed and she continued to be given medication. At 18 months, doctors declared her still effectively HIV negative.

Then the mother and baby disappeared out of the medical system and doctors later found out that she stopped taking any medication at 18 months.

Cured!

Everyone was astounded when she reappeared just before turning two and still tested HIV negative. At two and a half, a full year after she had stopped taking medication, her HIV levels were still below detectable levels.

In all of these tests, although traces of the virus were still detectable, levels were so low that she was considered ‘functionally cured’. A functional cure means the virus is kept at bay without any treatment.

This was in early 2013 and it made big news. For the first time a baby had been cured of HIV. Seriously exciting!

The Berlin patient

Only one other person had ever been functionally cured of HIV, the so-called Berlin patient. His cure resulted from radical treatment for leukemia in which doctors pretty-much destroyed his immune system. A bone marrow transplant brought him back to health and importantly, this transplant came from a donor with a rare natural resistance to HIV infection.

People with this resistance are called elite controllers or long-term nonprogressors and are thought to include 2–4% of HIV sufferers.

The life-threatening and expensive Berlin patient procedure is not an option for the rest of the world’s 35 million HIV sufferers but here was a suggestion that an HIV cure may be possible. And everyone agreed that understanding exactly what had gone on with Mississippi baby might be a step towards this cure.

Hide and seek

One of the reasons curing HIV is proving so hard is because the virus lies dormant in the body, in hiding from all of the treatment options we currently have. As soon as the drugs stop, the virus reemerges. Scientists wondered if this time they had managed to kill off the virus before it could establish and go into hiding.

It was full-steam ahead for a major study of HIV treatment in infants until a couple of weeks ago.

A punch in the gut 

On 10 July, news broke that after 27 months of no medication, the Mississippi baby who is now nearly four year sold, once again has high levels of HIV in her body. At the same time cells that indicate a normally functioning immune system (CD4+ cells) have dropped. This means the virus is having an effect on her health, rather than simply lying dormant.

She had been monitored every six to eight weeks for 18 months and no one knows why the virus has suddenly reemerged now. Back on medication, her immune cell levels are recovering but the big questions are where did the virus hide? And why did it hide for so long?

Sadly the Mississippi baby now faces a lifetime of medication but scientists argue that despite her HIV reoccurrence being like a ‘punch in the gut’, there is still much we can learn from her. I guess time will tell.

This week, the 20th International AIDS Conference is running in Melbourne.

Links and stuff

• New York Times article announcing that baby had been ‘cured’ from March 2013
• Piece from the Conversation discussing the challenges of curing HIV (talks briefly about the Berlin patient) 
• Interview from AIDS 2014 conference about the Mississippi baby
• Fairly heavy scientific paper about controllers and long-term nonprogressors
• Nature article on the Mississippi baby