THERE鈥橲 no need to panic yet. But there are signs that HIV is fighting back against some of the main drugs now used to combat it, with resistant strains responsible for more than a fifth of new infections in the US.
At a meeting in Washington DC last week, it was reported that of 317 HIV-positive people who had had no previous treatment, 23 per cent failed to respond fully to one or more antiviral drugs. The biggest problems were with relatively new antiviral drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs), which block an enzyme vital for viral replication.
鈥淭he biggest problems were with relatively new antiviral drugs on the market鈥�
Advertisement
Lisa Ross, a virologist with GlaxoSmithKline Research in Triangle Park, North Carolina, found that 18 per cent of patients had a reduced response to NNRTIs, and 6 per cent were resistant to all three brands on the market. 鈥淲hether that low-level resistance would have any clinical relevance is unknown,鈥� says Ross. 鈥淚 don鈥檛 think we need to wean people off NNRTIs.鈥� On the plus side, resistance to other antiviral drugs, particularly older ones like AZT, has remained stable or declined.
