New research published in the International Journal of Drug Policy suggests that widespread use of thinner syringes could reduce HIV transmission among injection drug users who share syringes. Thinner syringes have less “dead space,” which refers to the space in a syringe that contains fluid even when the plunger is fully depressed. According to the study, certain behaviors and practices involved with injection and sharing syringes results in retention of blood in the needle. Syringes with less dead space will hold less blood.
The amount of blood that is in the syringe is important, because that determines the potential amount of HIV found in the syringe.
The authors found that the more common “fat” syringes have forty times more dead space than the thinner version and can hold a thousand times as much HIV. The thinner ones were originally manufactured in the 1960s as a better deliverer of insulin to diabetes patients.
HIV, an incurable disease that weakens the immune system, can be transmitted through blood, semen, vaginal fluid, and breast milk. Injection drug users can pass the disease to one another by sharing needles contaminated with trace amounts of virus. It is estimated that nearly 20,000 injection drug users were diagnosed with HIV in the US from 2004-2007.
Switching from use of fat needles to the thinner version could have dramatic effects on HIV transmission rates in countries with epidemics driven by injection drug users. In Russia, where most HIV infections occur through sharing contaminated needles, the study estimated that a switch to all thin needles by 2018 could prevent 260,000-280,000 new infections between now and 2030. Preventing new infections could mean huge savings in expensive HIV treatment drugs and services.
However, not all injection drug users will accept thin syringes. The study acknowledges that, depending on the substance being injected, syringes of different sizes are necessary. The size of the syringe may also be determined by where one is injecting – a deep vein versus a shallow vein. Thinner syringes can also sometimes be slightly more expensive in developing countries although their prices are roughly the same in most countries.
The study noted that no human trials have been conducted to demonstrate the effectiveness of such a switch. However, they encouraged needle exchange programs and governments to prioritize thin syringes because these trials are still many years away from completion.
More research is needed on how to encourage drug users to switch to thin needles and whether they will switch at all. Dr. William Zule, an author of the study, pointed out to The New York Times that users can get more drug from the syringes with less dead space, and that this could be a major selling point for the switch. Dr. Zule acknowledged, “That may not be politically correct, but to be successful, campaigns…need to be organized by, for, and in collaboration with people who inject drugs and their communities.”