Transmission of HIV from mother to child (vertical transmission) can be prevented by providing short-term antiretroviral therapy (ART) to the mother and just-born infant.

By the same logic, can HIV transmission be reduced or even be prevented in the general population by starting ART immediately after a person is found to be HIV positive immaterial of the CD4 count — an indicator of a person’s immune response status?

A paper in The Lancet journal makes a case for such a strategy. One of the authors of the paper is Reuben Granich of the Department of HIV/AIDS, WHO. The WHO will be discussing this strategy with experts early next year.

Reducing transmission

The chances of HIV transmission are higher when the viral load is more. So reducing the viral load will theoretically help reduce new infections. The authors, based on mathematical modelling, have said that starting a person immediately on ART will help reduce the number of new HIV infections by 95 per cent in ten years’ time.

Such drastic reduction in transmissibility is indeed very positive news. Even the reduction in the CD4 count can be countered by starting treatment early.

A normal person’s CD4 count is in the range of 800-1,300. Since HIV attacks the immune system, the CD4 count in a HIV infected person keeps reducing.

“The CD4 cells reduce at the rate of 60-70 per year [in the case of an HIV infected person],” said Dr. B. Rewari, National Programme Officer, ART, NACO, New Delhi. “This happens even in those who eat nutritious food and exercise regularly.”

The problems

But for all these advantages, starting ART when CD4 count is high is riddled with problems.

ART is known for its toxicity. And it manifests differently depending on CD4 counts. NACO’s experience is revealing. For instance, NACO found patients suffering from drug toxicity when ART was given when CD4 count was between 250 and 350.

“We are seeing more side effects when we start ART when the CD4 count is between 250 and 350,” said Dr. Rewari. “It is mainly due to Nevirapine.”

According to him, more caution is required before starting ART when the CD4 count is higher. “The toxicity is less when the CD4 count is below 200,” he noted.

If the toxicity is high even when the CD4 count is 250- 350, how wise will it be to start a person on ART immaterial of his CD4 count?

Drug resistance

Drug resistance is real. Very good adherence is mandatory to prevent drug resistance. India has seen how people stop taking TB medicines the moment they feel healthy. And this leads to drug resistance.

Hence the possibility of a person failing to adhere is all the more high when ART is given to a healthy person. And even if adherence is good, there are chances of a person developing natural resistance to ART.

These issues get magnified, as unlike in the case of TB, where the treatment is only for 6 months, ART treatment is for life.

Patients who develop drug resistance will need second-line treatment. And second-line treatment is very expensive. Since the paper is about public-health, will governments afford to provide expensive drugs to thousands of patients?

Much like WHO’s policy, the paper also advocates voluntary testing. Though it has taken into consideration that some individuals will never come forward to get tested, it appears that it has grossly underestimated this number.

Such individuals can continue transmitting HIV in the population. The real success will depend on how many people come forward to get themselves tested.

No personal gain

As a comment in the same issue of the Lancet points out, Reuben Granich’s approach is more for public-health benefits than personal gain for the patient.

More so, when drug toxicity and other problems far outweigh clinical benefits.

“The individual might gain no personal benefit from testing and early treatment…” notes the comment. It then states that “current studies of uptake of and adherence to ART represent the case when mostly sick people are motivated to seek care.”

Despite the toxicity issue, HIV transmission can be greatly reduced or even eliminated if ART is started early. But the strategy can prove to be counter-productive if it fails.

The best option will be to go aggressive with non-drug prevention strategies.

Published in The Hindu on December 4, 2008