KnowHow: What have been major bright spots in HIV/AIDS research in the last three decades?
Sharon Lewin: Without any doubt, one of the biggest medical feats in the last 50 years has been anti-retroviral therapy (ART). Since its discovery in 1996, ART treatment has only got better — it’s got simpler, it’s got cheaper and it has now much fewer side effects. Thanks to ART, a person with HIV can have normal life expectancy. At the beginning of the epidemic, not so many years ago, it was a terrible way to die. But, today, an HIV infected person can live long on medication, just like a person who suffers from diabetes or any other chronic illness.
Apart from this, ART drugs have helped bring down the infectiousness by 96 per cent. In another words, a HIV positive person on ART medication may still have low levels of the virus, but the chances of that person transmitting the infection to his or her sexual partner even if safe sexual practices are not followed are rather limited. This means that it has not just helped an individual but the whole community. That is a major advance.
Thanks to generic ART drugs, as many 11 million HIV infected people from low and middle-income countries can afford treatment. The annual cost of treatment is under US $ 200 for these poor patients; those in advanced countries pay around $12,000-15,000 annually.
Another great achievement has been that we have been able to bring down mother-to-child transmission from a high of 30 per cent to less than 1 per cent. Now, fewer than one in 100 HIV positive mothers passes on the infection to their babies.
KnowHow: Hasn’t the problem stabilised somewhat, considering that the number of HIV infections is not increasing at an alarming rate?
Lewin: There are currently 33 million known HIV patients. New infections have been coming down significantly in many countries. For instance, new infections in India have come down by 50 per cent in the last decade. Similarly, last year as many as 25 countries in Africa reported a 50 per cent reduction in new infections. Many countries are enjoying great success largely driven through treatments. The more people are on treatment, the less the disease is transmitted. But there are many parts of the world that do not share the same success story.
KnowHow: High-risk groups like drug addicts and same sex communities have been the focus of coordinated anti-HIV intervention programmes for quite some time. But hasn’t there been little success in reducing the infection among these groups?
Lewin: The reasons are different in different places. But by and large, discrimination and lack of access to the treatment still exist in many parts. Men who have sex with men in Australia, for example, solicit partners over the Internet and use drugs, so they often do not feel the need for practising safe sex. On the other hand, in many other countries, including parts of India, drug addicts seldom have access to clean needles. So checking transmission of the infection becomes difficult.
KnowHow: But there has been great success in many African countries...
Lewin: Apart from the availability of cheaper medicines, communication played a key role. In Africa, getting the message across to the affected community has been a lot easier. What we had in Africa was a sort of general form of epidemic — that is, an infection that is spreading mainly through the heterosexual route. So the campaigners could effectively target women. Yes, their poor education levels were a stumbling block initially. But once they started seeing results in people who have been on treatment, the word got around.
But, there are many challenges still. For instance, nearly 1,000 new cases of infection are reported from South Africa every day. Similarly, in India, 15,000 of 100,000 new infections reported annually are from newborn babies. Why are so many babies born with HIV infection when ART is so effective in stopping the transmission? A course of ART during the third trimester of pregnancy is all that required to prevent mother-to-child transmission.
KnowHow: That brings me to the case of the Mississippi baby. Is the baby doing well?
Lewin: Yeah, that was an interesting case. More than three years ago, this baby girl was born in Mississippi in the US to a HIV positive mother, who didn’t know that she was infected. The baby was given full treatment for 18 months immediately after she was born. Now she has been off medication for nearly two years. She has very low levels of virus still. So, the baby is infected. Hopefully, she may not need another course of treatment.
KnowHow: Have this and other stray cases of infection remaining at very low levels despite stopping medication bolstered the quest for a cure for HIV?
Lewin: The word “cure” is a bit confusing for people. When we think about a cure, we think of how we cure sore throats or how you cure an infected leg. We give someone antibiotics for a few days, then it’s gone.
HIV is a bit different. We think of it as a bit more like cancer — once it is there in the body, it’s there forever. But, can we put it in permanent hibernation? And that is now often referred to as a functional cure.
Currently, a person who gets infected in his 20s or 30s needs to have treatment for 40 or 50 or 60 years, depending on how long that person lives. The financial burden of HIV/AIDS is huge and it is expected to cost $ 50 billion by 2030.
What happens when a person stops the treatment after many years of ART therapy? The virus comes straight back, usually in 2-3 weeks. This is because during the treatment the virus goes into hiding, waiting for an opportune moment to strike.
So what is key to finding a functional cure is waking up the virus from its hiding place and destroying it. Last year, in our lab we demonstrated that we could wake up the virus using an anticancer drug.
The big challenge is to find a way to permanently knock out these last ‘reservoirs’ of the virus or to boost the immune system to such levels that virus perpetually remains at very low levels.