HIV treatment works best when the virus has not yet learned to fight back. But that learning happens. A new look at data from 826 people in 14 countries shows how HIV adapts to specific medicines. The findings reveal that the type of HIV virus and the drugs a person took before matter a lot.
Most infections in this group were caused by Subtype C. This is the most common version of the virus in many parts of the world. However, the virus had already built up defenses against common drugs. High-level resistance was found in 88.3% of cases for lamivudine and emtricitabine. Resistance to efavirenz was even higher at 92.8%. Nevirapine resistance reached 96.8%.
Specific mutations tell the story of past treatments. The M184V mutation appeared in 86.2% of cases. This mutation makes the virus resistant to certain drugs. The K103N mutation was found in 57.8% of cases. People who took nevirapine or rilpivirine before were less likely to have this specific mutation. But those who took zidovudine were more likely to have a different resistance mutation.
These patterns change based on where a person lives and what they took before. The study found that K103N mutations were more common in African and South American countries. This shows that HIV evolves differently in different places. Doctors must know these local patterns to pick the right medicine. Ignoring them could leave a patient with a virus that no longer responds to standard care.