Question about dry blood

[Worried252]

I have a question about the hep c risks associated with dry blood. Just to make sure I'm correct. I've read other places and here about all of the risks so I think I know most of what I need. But the dry blood risk concerns me. Is dry blood only a risk on say a tooth brush/needle? Or how about if there's dry blood on a rail and you touch it with a cut on your hand? Any answers would be appreciated

[Lynn K]

Dry blood on a handrail has surely degraded being exposed to the environment.

We are advised not to share personal hygiene items like toothbrushes because there could be a very small theoretical risk. The risk from a needle with blood is if it should break your skin and push the infected blood inside your blood stream.

However,  even in the situation where a health worker experiences an accidental needlestick involving a patient with known hep c and the blood is fresh the risk is only about 1.8% so even in that situation still a very low risk

So no risk to exceedingly small risk.

If you have fresh cuts to protect them from infection in general you should bandage them.

[Mugwump]

If exposure to dried blood was a significant risk then the population of cities where there are large numbers of infected individuals would not be constantly increasing! I had HCV for very many years not knowing if I infected others before testing for the disease was available. During the HCV epidemic scare of the late 1980's when the disease was first isolated and before I was diagnosed I must have exposed others in this fashion especially my family. Non of whom has tested positive for exposure to HCV.

The fact is that the encapsulation of active virus breaks down with exposure to O2. It is effectively killed by exposure to dry air or agents like very mild hydrogen peroxide in a standard quat dilution (used on food preparation tables, knives and all surface sanitation). As well as a standard sanitizing agent in places like operating rooms but at higher levels of concentration for obvious reasons.

Much more concern for all of us is exposure to bacteria that has become resistant to all current treatments and antibiotics. Some dangerous bacteria have the ability to resist more readily standard sanitation and their protein encapsulation and capacity to survive exposure to the air and heat is much higher than HCV, which cannot stand exposure to the air. Blood residue contained in an anaerobic environment like a used needle is a different story. In short contracting HCV requires an almost completely anaerobic incident for an infection transfer to occur.

Non infectious contact of inert virus in dried blood that has lost the viral encapsulation will not result in spread of the disease. Secondly it would require direct spread to an open membrane or wound with active intact virus in an aqueous anaerobic situation, like being stabbed with a knife with fresh blood on it during combat. Or something equally barbaric, say perhaps a cage fight to the death between numbers of HCV infected bare handed pugilists.

A great many people are ignorant of how HCV cannot spread other than by direct wet blood to blood contact. And this causes many to worry needlessly about the disease, which is indeed a great misfortune for those who are infected!