• Prevalence of Drug-Resistant HIV-1 Variants in Newly Infected Individuals during 1999-2000 (Poster 423)
  Authored by V. Simon, J. Vanderhoeven, A. Hurley, B. Ramratnam, D. Boden, M. Louie, R. Kost, K. Dawson, N. Parkin, J. P. Routy, R. P. Sekaly, and M. Markowitz
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Several studies continue to monitor for the degree of drug resistance seen in untreated persons. This monitoring is one set of information useful for not only describing the consequences of ongoing HIV transmission, but guides clinicians in the potential for needing a resistance test to guide the initial regimen, a practice that is still not considered standard.

This study reported on 61 recently infected people in North America, most of whom presented for care in the New York City area, and some from Montreal, Canada. Overall, they reported that 26% had some degree of potential resistance to at least one medication. However, when focusing only on high levels of resistance more likely to interfere with the expected potency of medications, about 7% showed a >10 fold loss of sensitivity to at least one medication based on phenotypic testing. This included higher level genotypic resistance to the non-nucleosides, nucleosides and protease inhibitors seen in between 5-10% of persons overall. They reported on three people whose virus contained mutations to multiple classes of medications.

This report continues to provide monitoring of the consequences of ongoing transmission. Those on medications and doing well on them are less likely to have resistance -- thus, it is worrisome that some will start with a virus that is likely to be more difficult to treat. This report fits in with many of this type that suggest this problem may continue to worsen over time. This also suggests that newly-infected people may be candidates for early resistance testing as the likelihood of identifying resistance appears to be increasing, and clinically these strains may be ultimately much more difficult to control.