WHO's `test and treat' policy is misguided: Experts

[Guest guest]

Scientists fear HIV drug resistance may rise

Experts say WHO's `test and treat' policy is misguided, could lead to serious

problems in countries such as India

Jan 14 2010 . Bangalore: The human immunodeficiency virus, or HIV, infection is

draining the global public health systems, has infected 2.7 million people and

caused two million deaths in 2008, but things could get even worse, warn

scientists—the emergence of a wave of drug-resistant strains of the virus could

hinder efforts to control the pandemic.

Using a complex network model that takes into account single-, double-, and

triple-resistant strains of the virus, a team of US researchers report in

Friday's Science that there's a threat to global public health from strains of

HIV that are resistant to traditional antiretroviral treatments.

This model, they say, can be used to predict drug resistance in any place where

individuals are being treated with antiretrovirals (ARVs) for HIV infection,

including India, where even the second line of ARVs are now part of the national

AIDS control programme.

This is a very " novel " study that discusses dynamics of transmission of the

drug-resistant HIV strains based on the data collected in San Francisco among

men having sex with men, says Ramesh Paranjape, director of the National AIDS

Research Institute in Pune.

" The finding that NNRTI (Non-Nucleoside Reverse Transcriptase Inhibitors, a

class of drugs) resistant strains are more likely to be transmitted and capable

of establishing new strains is a cause of concern, " adds Paranjape. " This is

because our first line regimens are NRTI (Nucleoside Reverse Transcriptase

Inhibitors) and NNRTI dependent. "

While using HIV prevalence and resistance data from San Francisco, the model

accurately reproduced the documented evolution of transmitted resistance in the

city over the past two decades. It showed, surprisingly, that many of the

drug-resistant strains which have evolved over the past 10 years in San

Francisco are much more transmissible than has been previously thought.

The research also reveals that while effective treatment has kept the

transmission of resistant HIV under 15% in San Francisco, a full 60% of the

resistant HIV strains in the city are capable of causing self-sustaining

epidemics.

Recalibration of the model for a new region would require prevalence and

treatment data such as the type and duration of the drugs being used, their

effectiveness in suppressing viral load and reducing mortality, rates of drug

resistance, and the fraction of people needing the drug who actually take it.

" This isn't just about San Francisco, " stresses senior author Sally Blower,

director of the Center for Biomedical Modeling and a member of the University of

California Los Angeles AIDS Institute. " San Francisco is like the canary in the

mine. In fact, the most significant implications of our work are for countries

where treatment is just being rolled out. "

Paranjape agrees, although he admits there is a need for generating more

systematic data in India. Based on current field data, the ARV resistance level

in India is " on a par with Europe, Thailand or Africa " , according to an expert

at an HIV/AIDS care and research organization in Chennai, who doesn't want to be

named because he is not authorized to speak to the media.

However, it's the likely scenario in developing countries that worries

researchers. Their modelling shows the proposed strategy for HIV elimination by

the World Health Organization could " inadvertently make things worse " .

The recently proposed " universal test and treat " strategy of WHO includes

universal testing every year and is based on first-line regimens.

Blower says this strategy has been decided based on WHO's modelling study

published in the medical journal Lancet and is simplistic, based on the

assumption that drug resistant strains would not evolve and be transmitted.

" If the WHO model included (as our model does) that drug resistant strains will

evolve and be transmitted they would find (as we have found) that HIV

elimination is very unlikely and that their strategy will lead to a great many

people becoming infected with drug-resistant strains, " says Blower.

" Therefore, I strongly believe that the WHO universal `test and treat' strategy

for HIV elimination is very misguided and could lead to very serious public

health problems in resource-constrained countries such as India. "

Though the Chennai expert says the WHO strategy will be implemented with

" appropriate human subjects' approval and ethical guidance only " , the present

findings build a strong case for using drug resistance data as a basis for

future strategy.

Notwithstanding the fact that the study is done among the homosexuals in San

Francisco, which is a fairly well- networked community, Paranjape says the study

provides an opportunity to " recalibrate the model and generate very important

information that may have impact on treatment policies " .

http://www.livemint.com/2010/01/14223129/Scientists-fear-HIV-drug-resis.html