^ ..what he said, +, on a different note from weak vaccines, but also when antivirals are exposed to it in a strength or duration as to not efficiently or effectively render it non-viable. Hence, when people dont take antiviral medications with adequate adherance, they ARE modifying it. the HIV virus, for example, mutates to become resistant to that antiviral combatant. Much like when someone has a bacterial infection, and doesn't take their antibiotics for the full course, the bacteria strain becomes resistant to that antibiotic, hence, multiple (antibiotic) resistant strains of bacteria like staph aureous yeilding MRSA. -brought about by the general public modifying the bacterial strain by taking their medications incorrectly or inappropriately. This is why it is so important for people with HIV to be consistantly adherant with their medictions as they can - so they don't develop resistance to a particular medication, much less a whole classification of antiHIV medications. HIV sucks.