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and Hepatitis.com Coverage of the
17th Conference on Retroviruses and
Opportunistic Infections (CROI 2010)
February 16 - 19, San Franciso, California
Hepatitis C Virus Can Survive in Syringes Up to 2 Months under Favorable Conditions
Elijah Paintsil and colleagues from Yale School of Medicine designed a study to test the hypothesis that the high prevalence of HCV among injection drug users may be due to the fact that the virus remains viable for long periods in contaminated syringes.
HCV transmission occurs 10 times more often than HIV transmission from an accidental needle stick, the investigators noted as background, and harm reduction measures such as needle exchange programs that have dramatically reduced new HIV infections have had a lesser effect on HCV incidence.
The study evaluated 2 types of syringes:
The researchers developed a new microculture assay for measuring viral viability in syringes, using a genotype 2 HCV strain that can live and replicate in a laboratory cell line. They first loaded syringes with HCV-spiked blood, then depressed the plunger to expel it; this process simulates "booting," when a user draws blood up into the syringe to mix with the drug before injecting it.
immediately or after a storage periods of up to about 2 months, the
investigators flushed out the syringes and introduced the recovered
virus into cell cultures. Syringes were stored at 3 different temperatures:
40ºF (4ºC), the temperature of an average refrigerator; 72ºF
(22ºC), or room temperature in a temperate climate; and 98ºF
(37ºC), equivalent to body temperature or a very warm climate.
Based on these findings, the researchers concluded that survival of viable HCV is dependent on syringe type, as those with detachable needles "appear far more likely" to transmit the virus.
"Lower temperature preserves HCV viability in low void volume syringes more than in high void volume ones," they continued. "HCV and HIV survival in low void volume syringes show similar time course, but HCV appears to survive longer than HIV in high void volume syringes."
Speaking at a press conference following the presentation, Paintsil said it is "probably advisable" for needle exchange programs to offer the smaller insulin syringes, but acknowledged that individuals who inject hormones (e.g., transgender people, body-builders) prefer larger ones.
The most important thing, he emphasized, is to distribute enough needles so that people do not have to share, and to promptly remove used needles from circulation.
In response to a question about whether HCV transmission among injection drug use varies between warm and cold climates or between summer and winter, he said that was excited about exploring this possibility.
Yale School of Medicine, New Haven, CT.