As many as 21 million people worldwide inject drugs, putting them at heightened risk for infection from blood-borne pathogens such as the hepatitis C virus (HCV), especially if syringes are shared.
A newer type of syringe designed to reduce HCV transmission by decreasing the so-called dead space — the volume that exists between the syringe hub and needle in comparison to standard and widely used high dead space designs — is not particularly effective, a new Yale School of Public Health-led study has found.
The research is published today in the journal PLOS ONE.
The study’s lead author, Professor Robert Heimer, and colleagues from the Yale schools of medicine and public health and the Center for Interdisciplinary Research on AIDS at Yale, concluded that the best of the low dead space (LDS) syringe-needle combinations still retained HCV infection, though it reduced the percentage of contaminated syringes to 65 percent compared to 98 percent found for standard high dead space (HDS) syringes.
None of the LDS syringes yielded percentages of comparable to insulin syringes with fixed needles. This design had the lowest proportion of hepatitis C infection; only 47 percent yielded viable HCV.
“Attempts to reduce HCV transmission through engineering design seemed to hold great promise to protect people who required syringes with larger volumes or needles with higher gauges than are found on insulin syringes,” said Dr. Heimer. “Unfortunately, none proved equal to the insulin syringes.”
The study is believed to be the first of its kind to assess the infectivity of hepatitis C in different syringe designs.
The LDS syringe-needle combinations were created over the past several years seeking a way to reduce virus transmission. Heimer and his team wanted to determine their effectiveness compared to other designs and whether they offer a safer alternative for people who inject drugs. They have not finished testing the syringes’ effectiveness at reducing other blood-borne pathogens such as HIV.
Providing comprehensive advice to prevent HCV transmission among people who inject drugs can include using LDS syringes, but with major caveats, Dr. Heimer said.
“We would advise that all individuals be informed that they should, first and foremost, always prepare drugs and inject them with new, sterile syringes,” he said.
Yale has been in the forefront of safer-needle programs to reduce the transmission of AIDS and other life-threatening viruses for many years. More than 25 years ago, a needle exchange program was initiated in New Haven to provide clean syringes to injection drug users to slow the spread of HIV/AIDS. That effort is still active and has been replicated in cities around the country.
Other Yale researchers involved in the current study are Dr. Mawuena Binka, Dr. Elijah Paintsil, Dr. Amisha Patel and Dr. Brett Lindenbach.