Which is NOT a preventive measure against the spread of HIV?

1. HIV spreads through blood, semen and vertical transmission (mother-to-child). 2. Condoms, safe blood screening and public education all reduce risk. 3. Sharing intravenous needles INCREASES the risk — it is a major transmission route. 4. So the "not a preventive measure" is the sharing of needles. _Source: syllabus Biology, Ch 7 "Human Health and Disease", §7.3_