Prevalence in primary infection

Wide variations in the prevalence of drug-resistant HIV in newly infected and treatment-naive individuals have been reported, together with differences in the rates of change in prevalence over time.

The CATCH study assessed resistance in over 1630 newly infected people in Europe between 1996 and 2002, finding primary resistance mutations in 10% of the group: nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations in 7%, non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations in 3%, and protease inhibitor (PI) mutations in 2%.1

An analysis of 2208 newly infected Europeans, first presented in 2003, found drug resistance in 11%.2 Similar rates were found in the SPREAD study of 1083 newly infected individuals from 17 European countries, with only 1% of the study group demonstrating dual-class resistance.3

In the United Kingdom, rates have varied with time, reaching a high around 2002 and then declining. From 1994 to 2000, 14% of newly infected individuals (seroconverters) had resistant virus, but 27% of people who contracted HIV in 2000 were infected with drug-resistant virus.4 In 2002, 27% of gay men identified as recent seroconverters in England, Wales, and Northern Ireland had resistance to at least one drug, compared to 20% in 2001.5

The prevalence of genotypic resistance in antiretroviral-naive individuals in the United Kingdom declined from 16% in 2002 to 12% in 2003 and 8% by the end of 2004. Most of the resistant cases were resistant to a single drug class (4.5% to NRTIs or NNRTIs, 2.1% to PIs); 17% to two drug classes, and 8% to three. Resistance in antiretroviral-experienced individuals is also showing a downward trend.6 7

Estimates of drug-resistant new infections in the United States also vary, from reports of 8 to 9% prevalence in treatment-naive people 8 9 10 to nearly 25% in others.11 12 Upward trends in overall resistance have been shown in many cities (3% between 1995 and 1998 versus 12% between 1999 and 2000).11 13 However, at least in San Francisco and New York, the prevalence of NRTI resistance has been declining: by 2001, to 6% in San Francisco and 3% in New York. 13 12

In the Swiss HIV Cohort Study, researchers found an 8% overall prevalence of transmitted drug resistance (6% NNRTI, 3% PI, and 2% NRTI class) during the period 1996 to 2005. Analysis of data from 858 participants found no temporal increase in the prevalence of transmitted drug resistance, with the exception of a rise in transmission of NNRTI-resistant strains from 0% in 2004 to 6% in 2005. An average of 3.4 drugs were affected by transmitted resistance. A 2% prevalence of dual- or triple-class resistance did not reflect a significant increase. Of gender, exposure category, ethnicity, and subtype, only infection with subtype B was a factor in the prevalence of transmitted drug resistance; however, this too was not a temporal change. The researchers found that effective antiretroviral treatment by itself can help contain the spread of primary HIV drug resistance; in particular, through the use of boosted PI-based regimens for first-line treatment regimens.14

References

  1. van der Vijver DAMC et al. Analysis of more than 1600 newly diagnosed patients with HIV from 17 European countries shows that 10% of the patients carry primary drug resistance: The CATCH study. Second International AIDS Society Conference, Paris, late breaker 1, 2003
  2. Wensing AMJ et al. Prevalence of drug-resistant HIV-1 variants in untreated individuals in Europe: implications for clinical management. J Infect Dis 192: 958-966, 2005
  3. Wensing AMJ et al. First representative prospective surveillance data on HIV baseline drug resistance from 17 countries in Europe; the SPREAD-programme. Fourth European HIV Drug Resistance Workshop, Monte Carlo, abstract 1, 2006
  4. UK Collaborative Group on Monitoring the Transmission of HIV Drug Resistance. Analysis of prevalence of HIV-1 drug resistance in primary infections in the United Kingdom. Br Med J 322: 1087-1088, 2001
  5. Rinck G et al. Trends in transmitted antiretroviral drug resistance in men who have sex with men attending genitourinary medicine clinics in England, Wales and Northern Ireland. Fifteenth International AIDS Conference, Bangkok, abstract PpC4713, 2004
  6. Health Protection Agency, Centre for Infections The UK Collaborative Group for HIV and STI Surveillance. A Complex Picture. HIV and other Sexually Transmitted Infections in the United Kingdom Health Protection Agency, 2006
  7. UK Collaborative HIV Cohort (CHIC) Study Steering Committee. Rate of AIDS diseases or death in HIV-infected antiretroviral therapy-naive individuals with high CD4 cell count. AIDS 21: 1717-1721, 2007
  8. Becker M et al. HIV-1 genotypic resistance in treatment-naive subjects enrolled in an observational trial (GAIN). Antivir Ther 7: S134, 2002
  9. Ross L et al. Prevalence of antiretroviral drug resistance and resistance mutations in antiretroviral therapy (ART)-naive HIV-infected individuals from 40 US cities during 2003. 44th Interscience Conference on Antimicrobial Agents and Chemotherapy, Washington, abstract H-173, 2004
  10. Weinstock H et al. The epidemiology of antiretroviral drug resistance among drug-naive HIV-1-infected persons in 10 US cities. J Infect Dis 189: 2174-2181, 2004
  11. Little S et al. Antiretroviral-drug resistance among patients recently infected with HIV. N Engl J Med 347: 385-394, 2002
  12. Simon V et al. Evolving patterns of HIV-1 resistance to antiretroviral agents in newly infected individuals. AIDS 16: 1511-1519, 2002
  13. Grant RM et al. Time trends in primary HIV-1 drug resistance among recently infected persons. JAMA 188: 181-188, 2002
  14. Yerly S et al. Transmission of HIV-1 drug resistance in Switzerland: a 10-year molecular epidemiology survey. AIDS 21(16): 2223-2229, 2007
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