There are no documented cases of HIV infection through contact with a needle or syringe discarded in a public place. Infection is theoretically possible, but injuries are usually superficial and blood in syringes may no longer be infectious. Exposure to HlV-infected blood is 0.3% (i.e. Three-tenths of one percent, or about 1 in 300). Stated another way, 99.7% of needlestick/cut exposures do not lead to infection. Blood is estimated to be, on average, 0.1% (1 in 1,000).
Although HIV does not generally survive well outside the body, it can survive for long periods of time (over 28 days) if hermetically sealed in syringe. There is a risk of HIV infection through intravenous injecting, subcutaneous injecting (injecting into the fat under the skin) and intramuscular injection.