Targeting antiretroviral treatment (ART) programmes to prioritize people with low immunity and a high viral load could be an effective HIV prevention strategy, say the authors of a new study published in The Lancet.
A study of 3,381 couples in seven African countries found that the risk of transmitting HIV to a sexual partner was a 92 percent lower if a patient was on ART. Infected participants with CD4 cell counts lower than 200 had the highest rate of HIV transmission, but ART had the greatest effect in reducing transmission from this group.
"The study found that the risk of transmission was higher, the higher the viral load of the participant. Once people started on ART and the viral load reduced, HIV transmission was very rare," said Dr James Kiarie, of Nairobi University, Kenya, one of the study's authors.
"Less than 50 percent of patients worldwide with CD4 cell counts lower than this threshold [200] are currently receiving ART," the authors noted. "Our data emphasise that ... [a reduced risk of transmission] would be achieved with maximum ART coverage of patients with CD4 cell counts lower than 200."
More lab tests
Whether more or less laboratory testing is needed for successful ART programmes has been debated at length. A Development of Anti-Retroviral Therapy in Africa (DART) clinical trial found that ART could be delivered safely and effectively in remote or resource-limited settings without laboratory monitoring.
Yet research in western Kenya found that more viral load testing was needed to prevent patients being unnecessarily placed on more expensive second-line treatment.
"Yes, these lab tests are expensive, and tend to be available only at large health facilities, but what we recommend is the development of cheaper tests that would allow viral load and CD4 to be tested the same way as HIV tests are done, to be available on as wide a scale as the HIV test," said Kiarie.
Treatment as prevention?
In a comment on the study, also published in The Lancet, Dr François Dabis of the Université Victor Segalen, in Bordeaux, France, noted that the results showed an urgent need for more clinical research into the concept of HIV treatment as prevention.
"Restricting antiretrovirals to those with advanced HIV disease is a barrier to the uptake of HIV testing," he said. "We should not wait for the results of further models, observational studies, or the ongoing couple-based prevention trial, before engaging in population-based trials of test-and-treat."
However, recent studies have suggested that the use of treatment as prevention could lead to the development of drug-resistant strains of HIV, especially in people already infected with the virus.
Some AIDS activists maintain that recommending increases in treatment and expensive tests is impractical in resource-poor settings, where funds for HIV are decreasing.
"It's all very well to recommend more treatment for people, more viral load testing and so on, but where is the money going to come from? In reality, people who are already on ART can't access viral load testing," said James Kamau, coordinator of the Kenya Treatment Access Movement.
"Many people in Kenya on the old national treatment guidelines [starting ART at a CD4 count of below 250] can't access treatment, so how do we move to put people with CD4 of below 350 [the new World Health Organization guidelines] on treatment? We need practical solutions, not more theoretical recommendations."
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A study of 3,381 couples in seven African countries found that the risk of transmitting HIV to a sexual partner was a 92 percent lower if a patient was on ART. Infected participants with CD4 cell counts lower than 200 had the highest rate of HIV transmission, but ART had the greatest effect in reducing transmission from this group.
"The study found that the risk of transmission was higher, the higher the viral load of the participant. Once people started on ART and the viral load reduced, HIV transmission was very rare," said Dr James Kiarie, of Nairobi University, Kenya, one of the study's authors.
"Less than 50 percent of patients worldwide with CD4 cell counts lower than this threshold [200] are currently receiving ART," the authors noted. "Our data emphasise that ... [a reduced risk of transmission] would be achieved with maximum ART coverage of patients with CD4 cell counts lower than 200."
More lab tests
Whether more or less laboratory testing is needed for successful ART programmes has been debated at length. A Development of Anti-Retroviral Therapy in Africa (DART) clinical trial found that ART could be delivered safely and effectively in remote or resource-limited settings without laboratory monitoring.
Yet research in western Kenya found that more viral load testing was needed to prevent patients being unnecessarily placed on more expensive second-line treatment.
"Yes, these lab tests are expensive, and tend to be available only at large health facilities, but what we recommend is the development of cheaper tests that would allow viral load and CD4 to be tested the same way as HIV tests are done, to be available on as wide a scale as the HIV test," said Kiarie.
Treatment as prevention?
In a comment on the study, also published in The Lancet, Dr François Dabis of the Université Victor Segalen, in Bordeaux, France, noted that the results showed an urgent need for more clinical research into the concept of HIV treatment as prevention.
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However, recent studies have suggested that the use of treatment as prevention could lead to the development of drug-resistant strains of HIV, especially in people already infected with the virus.
Some AIDS activists maintain that recommending increases in treatment and expensive tests is impractical in resource-poor settings, where funds for HIV are decreasing.
"It's all very well to recommend more treatment for people, more viral load testing and so on, but where is the money going to come from? In reality, people who are already on ART can't access viral load testing," said James Kamau, coordinator of the Kenya Treatment Access Movement.
"Many people in Kenya on the old national treatment guidelines [starting ART at a CD4 count of below 250] can't access treatment, so how do we move to put people with CD4 of below 350 [the new World Health Organization guidelines] on treatment? We need practical solutions, not more theoretical recommendations."
kr/kn/he
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