Gilead makes a drug called Truvada -- AKA Prep -- that was developed at US taxpayer expense, whose patents are held by the US government; Truvada is on track to eliminating the spread of HIV forever (people who are HIV positive but take Truvada are seemingly not infectious), but taking Truvada in the USA (where the patents haven't expired) is incredibly expensive, running $1,780/month, whereas in Australia, it's available as a generic for $8/month. If the widespread use of Prep eliminates the spread of HIV, it will be both a humanitarian victory and a practical one, with the American taxpayers' investment in HIV prevention paying off handsomely in the form of billions in medical and social spending saved.