Injecting drug users who inject on a daily basis are likely to experience more rapid changes in the genetic make-up of their virus, raising the possibility that drug resistance will emerge more quickly in IV drug users taking anti-retroviral therapy.
A team from Johns Hopkins School of Public Health followed 15 injecting drug users for four years after seroconversion, and mapped genetic changes in the virus's coat in each individual. They found that drug users who injected on a daily basis exhibited a rate of virus diversification over 60% higher than non-injectors. This suggests much higher rates of virus turnover in active injectors, say the researchers. If similar mutation rates are found in the genes encoding reverse transcriptase and viral protease, drug resistance could emerge more quickly in regular injectors, especially if viral load is incompletely suppressed.
The full text of this report is available free in the October edition of the Journal of Infectious Diseases.