04 March 2013

A different perspective on HIV news

Several news outlets ran laudatory articles about a baby who was cured of HIV infection after being put on anti-retrovirals 31 hours after birth. The press has greeted this finding with tremendous enthusiasm. Although my knowledge of HIV admittedly pales to that of an infectious disease specialist, I'm more guarded about the significance of this case report.

First, this finding has not yet been published in a scientific journal, so the scientific community cannot satisfactorily assess its credibility. Science has a tradition of peer-review, and it is frustrating that the press is trumpeting this "cure" when the rest of the scientific community doesn't have the tools to confirm its veracity.

But even if the report is confirmed, while it would be cool, I would think that it would constitute only a slight advance in our understanding of the disease.

Our current understanding of HIV is that once it gains a foothold in the body (by infecting particular reservoirs of dormant immune cells), it is impossible to eradicate completely. Our current medications can dramatically decrease the viral rate of replication and largely contain the virus to those cells that are already infected. Not only does this decrease the burden of disease and lengthen patients' lives, but being on antiretrovirals seems to reduce the infectivity of the bodily fluids of HIV-positive patients (e.g. their semen contains fewer virus particles).

According to press reports, this baby was found to have viral genetic material in his (or her) blood and was immediately started on antiretrovirals. In subsequent tests, although viral particles were detected, no evidence of active viral infection could be found.

The report of a cure strikes me as consistent with our current understanding of HIV works. If some of the baby's cells had been infected with HIV, but the infection had not yet made it into the reservoirs of dormant immune cells, then a cure would be a foreseeable outcome. It's the same reason why health-care workers are given antiretrovirals as prophylaxis when they get a needlestick from an HIV-infected patient: it decreases the odds that the viral infection will enter the reservoirs of dormant immune cells. In short, if this baby was "cured", it would probably mean that it had never been fully infected.

My guess is that this report will change the way that HIV-infected newborns are treated. There will be a new emphasis on detecting HIV infection and on starting therapy as soon as possible.

One point that people seem to be missing is that this baby was probably infected because her mother did not obtain prenatal care. Proper prenatal care dramatically reduces the likelihood of passing HIV to one's newborn. Is prenatal care easily accessible to all pregnant women? For all of this talk in the press of cure, I wish there was some mention of the very good tools of prevention we already possess.