In 2011, around 1.7 million people died of AIDS, according to UNAIDS, the UN agency that tracks the disease. It's estimated that between 300,000 and 330,000 babies are born every year with congenital HIV (human immunodeficiency virus) infection passed on by their mothers. In many Third World nations, infants go untested and the disease is discovered only when the symptoms of full-blown AIDS develop.
It can take years, even a decade or more, for HIV-positive individuals to develop AIDS and the syndrome can be arrested by administering cocktails of anti-retroviral (ARV) drugs. But HIV virus is incredibly difficult to eradicate. ARV treatments destroy cells in which HIV is replicating. But the virus usually goes dormant and waits for another opportunity to re-infect. Doctors tend to be very cautious in declaring "cures", waiting for multiple HIV-negative tests over long periods because of HIV's ability to go dormant and resurrect.
More From This Section
But in the Mississippi case, and in many Third World cases, the mother had not undergone HIV testing during pregnancy. Her HIV-positive status was discovered only when she was in labour. In such circumstances, the baby is born HIV-positive.
The normal method of treating infants with congenital HIV is to give babies very low doses of drugs designed to suppress HIV. This procedure usually starts at around six weeks after birth.
However, in the Mississippi case, the infant doses happened to be unavailable at the hospital when the mother went into labour.
More or less out of desperation, the paediatricians at the University of Mississippi Medical Center treated the infant girl with adult doses of a three-drug ARV cocktail within two days of birth. They continued the treatment for 18 months before they lost touch with the child and her mother. After a 10-month hiatus in treatment, when the child reappeared for testing, she tested HIV-negative.
Almost three years down the line and a year after the treatment ceased, the toddler shows no signs of AIDS and highly sophisticated tests show that there are very few traces left of HIV. Apparently, the early induction of ARVs destroyed the HIV before it could go dormant. So, this has been declared a functional cure. It remains to be seen if it can be replicated in other cases of congenital HIV. If it can, it would be a huge breakthrough. The congenital segment represents a substantial chunk of the 2.5 million estimated annual infections.
The first, and so far only declared "functional cure" of AIDS in an adult also occurred in desperate circumstances. The "Berlin Patient", Timothy Ray Brown, had leukaemia (blood cancer) as well as being HIV-positive. The only way to treat Brown, an American resident in Berlin, was through a bone marrow transplant, which would improve his haemoglobin (red-cell count) and recreate his compromised immune system. This entailed completely destroying his extant immune system to prevent transplant rejection. This is a highly dangerous procedure.
As it happened, doctors at the Charite University Medicin Berlin found a compatible bone-marrow donor with a rare genetic mutation that offers natural protection against HIV. The transplant worked and six years later, Brown is still free from the disease (and from leukaemia).
The Berlin case led researchers into several promising lines of investigation. They started experimenting with the possibility of inserting genes with natural HIV immunity into cells taken from HIV-positive patients. Two other cancer-HIV patients who received bone-marrow transplants have also remained HIV-negative. But insufficient time has elapsed for these cases to be declared definitive cures. Experiments at the University of California, Los Angeles, involving genetically engineered stem cells to fight HIV-infection in mice have also shown very promising results.
According to UNAIDs, about 35 million people are HIV-positive at the moment and HIV-positive people are living longer. The cost of ARVs has reduced drastically. This is in no small part owing to companies like Cipla fighting price wars in selling ARVs. A one-year ARV course, which used to cost $10,000 in 2001, is now down to $100. The more aggressive use of ARVs and wider screening of the general population could reduce societal risks and lead to a better quality of life for the HIV-infected. Finally, science may be gaining the upper hand.