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Trends in Transmission of Drug Resistant HIV
Reported by Jules Levin
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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
www.natap.org/2002/HIVDrugRes/day5.htm
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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