Understanding risk factors

In order to understand whether someone has been put at risk of contracting the hepatitis C virus (HCV) it is important to understand that a number of factors need to be in place for infection to occur:

•    Firstly, the virus has to have a means of entering the body
•    Secondly, there has to be sufficient quantity of virus
•    Thirdly, the virus needs to be of a specific quality.

While blood is not the only body fluid that can contain the hepatitis C virus, it is in the blood that the highest concentrations of virus are found and as a consequence only a small trace of blood may have sufficient virus present to cause infection. Furthermore, the virus can survive in dried blood on everyday surfaces at room temperature for at least 16 hours but not longer than 4 days. However, it can survive longer in a confined environment such as inside a syringe.
The virus must have a means of entering another person’s body in order for transmission to occur. If the virus is able to directly enter the bloodstream via a needle or through a blood transfusion then the risk of infection is very high.
These three factors form the basis for assessing risk reduction. In addition it is useful to consider the number of times a person may have been exposed to the virus. A single exposure to an infected needle may be all that it takes for transmission via this route, whereas a single exposure via unprotected sexual intercourse is unlikely to result in transmission.

Because hepatitis C is so efficiently transmitted by the sharing of IDU equipment, the disease has come to be stigmatised as a drug-addicts' disease. In fact there are a multitude of ways you could have been put at risk of contracting the disease. Beyond that, some people who have contracted the disease have no known risk factors.

In order to determine whether you may have been exposed to risk of hepatitis C infection it would be useful to ask yourself whether you have been exposed to any of the known transmission routes and how frequent those exposures may have been. It is easy to determine some transmission routes as high or low risk, but for many potential transmission routes estimating risk is very difficult because it depends on a number of immeasurable factors.

For example, risk from clippers used by hairdressers would depend on how or whether they are cleaned, how often they are cleaned, how many customers may be exposed to the same clippers, how the clippers are used, and probably many other variables.