BMJ  2006;332:179-180 (21 January), doi:10.1136/bmj.332.7534.179-c

Letter

Resistance to HIV drugs in UK may be lower in some areas

Editor—The UK Group on Transmitted HIV Drug Resistance reports an estimated prevalence of transmitted HIV drug resistance of 14.2% between 1996 and 2003 which is increasing over time.¹ Using the same definition of drug resistance as the UK group, a study of primary HIV infection at St Mary's Hospital, London, showed that the prevalence and annual incidence of transmitted drug resistance have remained low and stable, at 6% (9/140) between 2000 and 2005. Resistance to nucleoside reverse transcriptase inhibitors was detected in 1/9, to non-nucleoside reverse transcriptase inhibitors in 5/9, to protease inhibitors in 1/9, and to more than one class of drug in 2/9.

The disparity in estimated prevalence of transmitted drug resistance is interesting and may reflect the differences between the two cohorts. In our cohort, all individuals acquired HIV within six months of baseline genotyping and were predominantly white with homosexually acquired B clade viruses (125/140, 89%).

The UK group described a large cohort of 2357 individuals with chronic HIV infection presumed to be naive to antiretroviral therapy. Of these, 172 (7%) were infected within the previous 18 months, 22% of whom had drug resistance. The country of acquisition of HIV infection may contribute to the disparity since the use of antiretroviral therapy globally differs considerably, as in the use of nevirapine to prevent mother to child transmission.^{2 3} Most of our patients (98%) were infected in the UK. Although this was not assessed by the authors, the diversity of viral clades reported implies greater HIV acquisition outside the UK.⁴

The advantage of prospectively recruiting individuals with primary HIV infection and confirmed naive to antiretroviral treatment avoids the difficulties acknowledged by the group in relying on treatment histories reported by patients and doctors. Prevalence estimates of transmitted drug resistance in newly infected patients may not therefore be generalised to patients with established infection who are reportedly treatment naive.

Section of Infectious Diseases, Faculty of Medicine, Imperial College, London W2 1PG julie.fox{at}imperial.ac.uk

Section of Infectious Diseases, Faculty of Medicine, Imperial College, London W2 1PG

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Competing interests: None declared.

References

1. UK Group on Transmitted HIV Drug Resistance. Time trends in primary resistance to HIV drugs in the United Kingdom: multicentre observational study. BMJ 2005;331: 1368. (10 December.)[Abstract/Free Full Text]
2. McIntyre J. Prevention of mother-to-child transmission of HIV: treatment options. Expert Rev Anti Infect Ther 2005;3: 971-80[CrossRef][Medline]
3. Jourdain G, Ngo-Giang-Huong N, Le Coeur S, Bowonwatanuwong C, Kantipong P, Leechanachai P, et al. Intrapartum exposure to nevirapine and subsequent maternal responses to nevirapine-based antiretroviral therapy. N Engl J Med 2004;351: 229-40.[Abstract/Free Full Text]
4. Tatt ID, Barlow KL, Clewley JP, Gill ON, Parry JV. Surveillance of HIV-1 subtypes among heterosexuals in England and Wales, 1997-2000. J Acquir Immune Defic Syndr 2004;36: 1092-9.[ISI][Medline]

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Relevant Article

Time trends in primary resistance to HIV drugs in the United Kingdom: multicentre observational study

UK Group on Transmitted HIV Drug Resistance
BMJ 2005 331: 1368. [Abstract] [Full Text] [PDF]