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How will the 3 by 5 Initiative deal with HIV drugs resistance?


Reference Number: WHO/HIV/2003.10

Currently, few persons from countries with limited resources have access to life-preserving antiretroviral (ARV) drugs. On 1 December, WHO will launch the 3 by 5 Initiative to expand treatment access programmes in resource-limited settings so as to provide 3 million persons with ARVs by December 2005.

Although it is universally recognized that HIV therapy has remarkably reduced HIV-related mortality, many critics remain concerned that the widespread use of ARVs has the potential to select drug-resistant populations of HIV strains that would make continuing ART increasingly difficult. With the World Health Organization’s (WHO) commitment through the 3 by 5 Initiative to increasing access to ARVs in resource limited countries, additional concerns are being raised about the reasonable likelihood that HIV resistance will not only emerge but also be accelerated by the ART programme, especially if ART drug use is inappropriate, excessive or irrational; or adherence to ARVs is poor.

When resistance emerges, an anti-HIV drug that was once effective becomes less able to fight the virus. That drug will need to be switched to a more expensive second-line alternative. The consequences of drug resistance include treatment failure, increased direct and indirect health costs, transmission of resistant the strain to treatment-naive subjects and the need to develop new anti-HIV drugs. Thus, HIV resistance has been recognized as a serious threat to the effi cacy of current HIV treatments.

It is not clear that resistance will either emerge or spread more rapidly in countries with limited resources. However, while uncertainties remain about the future dimension of the resistance problem and the impact it will have on our ability to effectively treat HIV, there are clear concerns that resistance could become a major public health problem. It is difficult to quantify this threat because, until now, it has been extremely diffi cult to collect reliable, standardized and comparable global data on the level of HIV drug resistance and its transmission. Only a small number of patients in resource-limited settings have been on ART and almost all have had to pay for treatment. Financial constraints have fuelled poor adherence and inadequate therapy, with the appearance of resistance. This does not mean public sector; free-of-charge services will have the same problems. Indeed, adherence may be better in Africa than the United States of America.

Data on the prevalence of resistance among treatment-naive subjects in countries where ARV drugs have been available for years ranged from 5 % to 27 %. For example, a study performed in Boston in 1999 indicated that resistance mutations were present in 18 % of the subjects examined. Recent data from 17 European countries showed that 10 % of the untreated patients carry drug resistant virus. There are almost no data from countries that will implement ART programmes in line with the 3 by 5 target.

The threat of increased levels of resistance is not a reason to decline providing life-prolonging therapy to persons in need. Instead, what is required is monitoring the emergence of resistance and developing approaches to reduce the emergence of resistance to ARV drugs. WHO and its partners intend to collect reliable and updated information on the prevalence of HIV-resistant strains as ARVs become widely available.

Three major public health questions need to be answered:

  • What is the level of resistance to ARVs in circulating HIV strains?
  • How is HIV drug resistance prevalence changing over time in different areas?
  • Is increased treatment availability causing a rise in HIV resistance?

To address these questions, WHO and its partners established the following objectives:

  • to track HIV drug-resistance prevalence and assess its geographical and temporal trend;
  • to understand more completely the determinants of resistance;
  • to identify ways to minimize its appearance, evolution and spread; and
  • to provide information to international and country-level policy-makers through a rapid and easily accessible dissemination system.

To achieve these objectives, WHO will:

  1. develop and maintain surveillance systems at national and regional levels that measure HIV drugresistance prevalence among newly diagnosed and treatment-naive subjects. This target population is easily accessible in any epidemiological setting and can provide information on drug-resistance transmission levels;
  2. develop and maintain monitoring systems to measure HIV drug-resistance prevalence among treated subjects;
  3. establish a global network of laboratories involved in HIV-resistance testing and support technology transfer in limited-resources countries; and
  4. support operational research in different aspects of HIV drug resistance surveillance.

The implementation of the WHO programme needs the involvement of the global HIV/AIDS scientific and public health community. As a first step, WHO has established a coalition of 50 of the world’s experts in the public health, policy, clinical management, laboratory and science of HIV drug resistance (HIVResNet), to develop guidelines on how to conduct resistance surveillance in different setting and population groups.

On 1 December 2003, WHO Guidelines for HIV drug resistance surveillance in newly diagnosed and treatment-naive HIV subjects will be launched on the WHO web site. The Guide will address important aspects of a good, quality surveillance system such as sampling, data collection, laboratory testing, data management and analysis, quality control and ethical issues. The development and implementation of the HIV-resistance surveillance system will be primarily supported in those countries that WHO has identified as high-burden countries and where ARVs, currently not available, will be initially assured.

The acquisition of data on HIV drug resistance prevalence in those areas will allow a base-line picture that can be compared with data obtained over time. By contrast, HIV drug-resistance monitoring in treated subjects will be supported in those resource-limited countries where a small number of more wealthy individuals have had access to ARVs for two to three years.

The acquisition of data on HIV drug resistance prevalence in those areas will allow a base-line picture that can be compared with data obtained over time. By contrast, HIV drug-resistance monitoring in treated subjects will be supported in those resource-limited countries where a small number of more wealthy individuals have had access to ARVs for two to three years.

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