HIV Transmission and Primary Drug Resistance

Transmission of HIV viruses harboring resistance mutations is already a major concern in developedcountries, with the potential to impact on therapeutic strategies. Several factors influence the transmissionof such viruses, including viral replication fitness and transmission fitness, although behavioralcharacteristics must also be considered. Rates of transmission of specific mutations are relatedto therapeutic strategies. Reports of the transmission of multidrug-resistant viruses shouldalarm the medical community. An additional concern is the use of monotherapy with nevirapine forthe prevention of mother-to-child transmission of HIV in developing countries as this practice selectsfor resistance to nonnucleoside reverse transcription inhibitors and could limit future therapeuticoptions of both the mothers and infected children. HIV treatment guidelines have evolved, shiftingfrom more aggressive to more conservative approaches. This change of strategy has had a directimpact on the prevalence of drug-resistant virus in the population and the transmission of resistantviral species.