R. PRASAD The presence of drug resistant strains may be found even in HIV infected people who have never been on antiretroviral drugs Drug resistance may arise even when there is good compliance as the virus keeps mutating Of the 60 patients tested so far in a hospital in Chennai, 45 failed for the first-line drugs Transmitted resistance: In a study conducted at YRG Care, Chennai, of the 50 volunteers who had never been on antiretroviral drugs, about 14 per cent were found to have viruses with mutations that may lead to drug resistance. Four years after starting the antiretroviral therapy (ART) programme to treat people infected with HIV, efforts are underway to determine the extent of drug resistance in the treated population. That drug resistance is present is well known. The necessity to provide second-line drug treatment to people who are not responding to the first line drugs is a testimony of drug resistance in the population. Drug resistance may come up in two ways. The most common cause is when patients either fail to take the drugs regularly or stop taking the drugs sometime after the treatment has begun. But even when there is very good compliance, drug resistance may arise as the virus continuously mutates leading to treatment failure. "About 3 per cent of patients who have very good drug compliance would have developed resistance to the first-line drugs,' said Dr. Rajasekaran of the Chennai based Government Hospital of Thoracic Medicine. According to him, about 15 per cent loss of efficacy of the drug can be seen even when the compliance is good leading to treatment failure. Currently the Government Hospital of Thoracic Medicine provides antiretroviral drugs to 6,400 patients. "The condition of around 180 would not have improved from first-line treatment [due to treatment failure],' Dr. Rajasekaran said. The YRG Care at Chennai has also looked into drug resistance. About 370 of over 3,000 patients on antiretroviral therapy (ART) at YRG Care, have been found to be drug resistant. According to Dr. P. Balakrishnan, Microbiologist at YRG Care, the actual number may be more as many do not get themselves tested as they cannot afford to pay for the tests. Widely prevalent About 350 patients from other centres, either in Chennai or elsewhere in the country, have also been found to be drug resistant. YRG Care has a facility to test for drug resistance and they have been testing for it since 2005. The facility is accredited by the National Institute of Health, U.S. Incidentally, the presence of drug resistant HIV strains is not restricted to patients who are on antiretroviral treatment for HIV. It may be found in people who have never been on antiretroviral drugs. These are people who have been infected with the drug resistant strains. A study was conducted by YRG Care to understand drug resistance in people who were never on antiretroviral drugs. The results were published in 2005 in the journal AIDS Research and Human Retroviruses. "Of the 50 volunteers who were tested, about 14 per cent were found to have viruses with mutations that may lead to drug resistance,' said Dr. Balakrishnan. Two programmes The National AIDS Control Organisation (NACO) has initiated two programmes this year to study drug resistance in people who are on antiretroviral drugs as well as those who have been recently infected but not on antiretroviral drugs. The Government Hospital of Thoracic Medicine is one of the two centres to study drug resistance in people leading to treatment failure. The other centre is the Mumbai based J.J. Hospital. It is a pilot study to know the feasibility of implementing the second-line drugs in a public health programme. Treatment failure Only those with above 95 per cent drug adherence are considered for drug treatment failure assessment. "Of the 60 patients tested so far, 45 have been found to have failed for the first-line drugs,' said Dr. Rajasekaran. "Already 38 are on second-line drugs.' The target sample size is 100 patients. It is then validated based on the viral count. The CD4 count serves as an indicator of the person's immune response. The other programme is to know the drug resistance in people who have never been on ART. Three hospitals