Monday, August 30, 2010

Hepatitis C and its transmission........something to know!

I came across this article from Yale(presented at the 17th CROI in Feb 2010), where they did a research on the Survival of hepatitis C virus in the syringes ..mainly with respect to intravenous drug users, as the main form of transmission of Hep C in US is intravenous drug abuse(IVDA). Eventhough HIV and HCV almost have the same mode of trasmission, there are differences in their prevalance.For example...in places where HIV prevalance is 1-10 %,the HCV prevalance has been around 40-50%. This is likely due to longer survival of HCV.

Ok...what they studied in Yale is ....loading insulin and tuberculin syringes (both are commonly used by IVDA) with a lab strain of Hepatits C virus, and they stored the syringes at varying temperatures of 4 C(fridge temp), 22 C(room temp), and 37 C(autoclave temp) for up to 63 days. They checked for viability of HCV. The insulin syringes did not show viable HCV beyond day 1 at all temp except 4C where it was viable until Day 7
The tuberculin syringes there was 96%, 71% & 52% viability for HCV at temp of 4C, 22C, & 37C respectively, at 7 days.
This is likely due to the high void volume ( volume left in syringe after injection) in case of the tuberculin syringe.This study gives us some idea about the transmission of HCV on syringes. Since this study has been done on lab strains, it may not apply for the actual HCV. With this ..I will leave you to decide on the final sentence..

This gives us something to add to our history taking skills..when it comes to IVDA. And we can add this to our counselling skills as well (if we have time!!). Preventing needles is the best way to prevent HCV.But if not possible..then may be using an Insulin syringe instead of a tuberculin syringe may help. This will be a advice from me to my patients until we have any further compelling evidence to change this.

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