But HIV transmission due to needle sharing could nearly be eradicated by merely changing the design of the syringe.So says a study in the international journal of Drug Policy.When the plunger on a syringe is fully depressed,a small amount of fluid stays trapped in what is known as the dead space,by reducing the amount of dead space in the syringe design,researchers say they can reduce the amount of infectious blood trapped inside by a factor of 1000.And thus,vastly reduce the number of viral particles available to spread disease.

　　Using a simulation model,the authors found that switching to low-dead-space syringes would reduce annual HIV infection from Syringe sharing to nearly zero within eight years.

　　Although there are still a number of barriers to making low-dead-space syringes available worldwide,the authors say this low-cost invention could help keep drug users and their families disease free.

　　Thanks for the minute,for Scientific American 60-second Science,I'm Gretchen Cuda Kroen.