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Trends in Transmission of Drug Resistant HIV
Reported by Jules Levin
  In the August 8th issue of the New England Journal of Medicine Susan Little reports a study that had been previously reported at conferences which shows an increase in transmission of resistant virus among patients she studied in 10 US cities. Her findings are reported below. I think there is little question but that the risk for acquiring HIV drug resistant virus is a serious concern today both for the patient and the public health. Several studies show that patients who acquire drug resistant HIV are at risk for a diminshed initial response after starting HAART; and a response might occur but fade more quickly. However, the latest information on trends in transmission of resistant virus was reported this Summer at the Resistance Workshop in Seville, Spain. A number of researchers reported that rates of transmission of resistant virus appear to be leveling off, not increasing. But, researchers at the meeting cautioned against reading too much into the trends reported in the studies at this meeting. Further research and discussion is needed to follow this question. Here is link to report on the studies reported on this question at the Resistance Workshop. News coverage of Little's NEJM article again show the imprecise and often unreliable nature of journalist reporting of HIV science in mainstream press.
Patterns & Trends in HIV Drug Resistance Transmission
NEJM, Susan Little study findings:
"Over the five-year period, the frequency of transmitted drug resistance increased significantly. The frequency of high-level resistance to one or more drugs (indicated by a value of more than 10 for the ratio of the 50 percent inhibitory concentration [IC50] for the subject's virus to the IC50 for a drug-sensitive reference virus) increased from 3.4 percent during the period from 1995 to 1998 to 12.4 percent during the period from 1999 to 2000 (P=0.002), and the frequency of multidrug resistance increased from 1.1 percent to 6.2 percent (P=0.01). The frequency of resistance mutations detected by sequence analysis increased from 8.0 percent to 22.7 percent (P<0.001), and the frequency of multidrug resistance detected by sequence analysis increased from 3.8 percent to 10.2 percent (P=0.05). Among subjects infected with drug-resistant virus, the time to viral suppression after the initiation of antiretroviral therapy was longer (P=0.05), and the time to virologic failure was shorter (P=0.05).
Conclusions The proportion of new HIV infections that involve drug-resistant virus is increasing in North America. Initial antiretroviral therapy is more likely to fail in patients who are infected with drug-resistant virus. Testing for resistance to drugs before therapy begins is now indicated even for recently infected patients."
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