“Inexperienced physicians treating patients with HIV/AIDS pose a risk factor for the development of drug resistance,” said John Mellors of the University of Pittsburgh, during an IAS-WHO satellite meeting on HIV drug resistance on Monday.

Roberto Siliciano, in his address to the first plenary session described the mechanism by which HIV infection persist in infected persons. When CD4 cells are infected, most die, but many revert to a resting state, which provides a reservoir for future resurgence of infection. With effective antiretroviral therapy (ART), the viruses in the resting memory cells are prevented from evolving, and those that are drug-resistant in the CD4 lymphocyte resting memory cells, will remain resistant, while those which are not resistant will also remain so.

Viral drug resistance is one of the major topics of discussion at AIDS 2002 and at the satellite meeting, Dr Mellors presented a scientific overview of current knowledge of drug resistance.

He provided some key points which have been learned:

· No antiretroviral drug is resistance-proof. HIV has evolved to escape selective pressure whether it be from drugs or the immune system

· Incomplete suppression of HIV replication leads to drug resistance. This is often associated with incomplete adherence; multiple drug resistance is found in up to 30% of people on HAART after two years

· Resistance can lead to disease progression and death unless the viral RNA is suppressed to below 50 copies/mL

· Resistant viruses can spread, and can affect initial responses to therapy

· Resistance is not inevitable. Careful choice of regimens can minimise or prevent resistance

In order to monitor drug resistance world wide the WHO is setting up a global drug resistance surveillance network, which will provide reliable guidelines based on geographical and temporal trends. It will monitor outcomes to determine what causes or exacerbates, and what prevents drug resistance. Surveillance will be linked to ART programmes.

One of the aims is standardisation of data collection. The WHO wants the surveillance programme to be useful to all involved from government and health care providers to the public and commercial enterprises.

AIDS 2002 Conference News produced by Health & Development Networks/Key Correspondent Team