Outside of Africa drug injection is a leading vector of HIV transmission. Drug users usually inject directly into their bloodstream. In order to make sure that the needle has struck a vein the drug user will draw a little blood back into the syringe before injecting. This leaves a drop or two of blood in the syringe which is injected into the blood of the next drug user to share the needle.

These tiny amounts of blood are enough to provide HIV an ideal opportunity to be transmitted. There is an approximately 37 percent chance of infection after being accidentally pricked with a hollow-bore needle. This chance is thought to be significantly higher if this the needle had been in the vein of an HIV-infected person or the viral load is high.

Drug-users who inject drugs also put their sex partners at risk. A UNAIDS report estimated that 90% of infections in heterosexuals in New York City can be traced back to sexual contact with a drug-user who had shared needles.

In South Africa sexual contact is by far the highest method of transmission for HIV. South Africa is increasingly becoming a destination and transit point for drug traffickers. We can expect that HIV transmission from intravenous injection will increase.