Understanding Risk
In order to understand what constitutes a risk and to therefore determine whether an individual has been exposed to risk it is important to understand that a number of factors need to be in place in order 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 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 for up to two weeks or more, it has even been suggested for up to 3 months. The virus must have a means of entering another persons body in order for transmission to occur. If virus is able to directly enter the blood stream 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.
What are the risk factors?
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.
The risk factors are arranged in alphabetical order, rather than from high risk to low risk, as for some transmission routes the risk factor isnt known. So you will need to look through them all.
Blood and blood products
In the UK since September 1991 all blood and blood products are screened for blood borne viruses. People in receipt of blood from transfusions or blood products (including clotting agents for haemophiliacs) may have been exposed to hepatitis C prior to 1991.
If you have had an accident or operation in the UK prior to 1991 that may have required you to have a transfusion of blood or blood products you may have been exposed to tainted blood. It is worth noting that you may not always be aware that you were given blood, especially if you were very ill. If you have received blood this will be recorded in your medical records.
The Global Database on Blood Safety indicates that 80% of the worlds population does not have access to reliable and safe blood. It is estimated that 43% of the blood collected in developing countries is not tested for HIV, Hepatitis B, Hepatitis C or Syphilis and globally 5-10% of infections are caused by unsafe blood and blood products. (World Health Organisation).
Drug use
Because between 30-80% of IV drug-users are reckoned to be infected with hepatitis C and because you put the potentially infected material directly into your blood stream, sharing injecting equipment is one of the most high risk behaviours.
If you have been an injecting drug user and shared any injecting paraphenalia - needle, syringe, spoon, filter water, even once, even if it was a long time ago, then you are at significant risk of having contracted the virus.
Sharing snorting equipment e.g. rolled bank notes or straws potentially poses a risk of transmission. This is because the lining of the nose is very thin and fed with a rich supply of blood. Cocaine for example is very corrosive to the mucous membranes of the nose. As a result traces of blood perhaps even too small for the eye to see, but still containing enough virus, can lurk on banknotes and straws. While there have been no documented cases, in theory the risk is significant. The risk is much lower than sharing IV equipment as it is not such an efficient method of transmission . Clearly if you have damaged nasal membranes and have shared straws or notes with a known IV drug user then the risk is higher.
Hairdressers/Barbers
The hepatitis C virus can be present in small traces of blood, often invisible to the naked eye. Equipment used by hairdressers and barbers including scissors, clippers and razors may have been exposed to infected blood and if not sterilised or cleaned between customers pose a risk of transmission. The likelihood of this happening is very difficult to estimate as it will depend on a number of variables. If you got cut at a barbers or hairdresser, particularly abroad in high prevalence countries, then you may be at some risk. However, blood does flow out of the body when you get cut which may lessen the chances of infection.
Haemodialysis
Haemodialysis for those with kidney failure is a known transmission route for hepatitis C. Haemodialysis involves the removal of waste products from the blood. This is done by passing a persons blood through an artificial kidney machine, and re-introducing the filtered blood back into the body. The risk of infection is increased in those who undergo long-term dialysis and has been estimated at between 10%-20%.
Household Transmission e.g. sharing razors and toothbrushes
Because razors, nail scissors, nail clippers, toothbrushes and possibly even towels may carry traces of blood, sharing them with an infected person may present a risk of acquiring hepatitis C. If the implement is tainted with infected blood and you sustain an injury from it, then the virus could be introduced into your bloodstream. Similarly, traces of blood which could contain virus can be present on toothbrushes and if shared by a person with bleeding gums or a mouth injury transmission is possible. The risk is hard to assess.
Medical and dental procedures
Invasive surgical and dental procedures pose a risk of exposure to the virus, especially in less developed countries. In developed countries healthcare workers are required to use new or sterilised equipment and observe universal control procedures that safeguard both patients and themselves; this does not, however, exclude all risks. In many developing countries these precautions may not be observed. If you have ever had a dental or medical procedure performed abroad, you may have been exposed to risk of infection.
A similar distinction also exists regarding infected doctors carrying out invasive procedures (particularly those where doctors are using sharp instruments but cannot see his or her own hands). This is not permitted in developed countries but this only guards against those whose infections are known. Many developing countries may have less stringent regulations.
Mother To Baby
The risk of transmission from mother to child is thought to be approximately 5%. The risk is higher in women who are co-infected with HIV. If you are pregnant or planning to have a child and are hepatitis C positive, it is important to discuss this with your consultant. Whether there is anything you can do to lessen the transmission risk is uncertain. There is some evidence that mothers with lower viral loads are less likely to transmit infection. It is not believed that caesarean delivery makes any difference. On the other hand breastfeeding if your nipples are bleeding is also believed to pose a risk.
Needlestick Injury
Needle stick injuries are an occupational hazard of many health care workers, including nurses, anaesthetists, dentists and laboratory technicians. If you know the needle or implement has been exposed to the blood of someone who has hepatitis C the risk is thought to be around 3.3% which is a 1 in 30 risk.
Piercing
Piercing is a potential source of risk unless all equipment is new or sterilised (sterilisation must be done ultrasonically in an autoclave) click here for more details and only new jewellery, preferably from a sealed package, is used. This equally applies to self-piercing. Most body piercing parlours in the UK operate to high standards. However, the situation differs across the country because regulation is carried out by local authorities in some cases, (most of London) by licensing and in other cases using byelaws. These can vary from area to area but the DoH have produced a model set of byelaws (click here) that set out the standards that you ought to expect from a piercing shop. You are unlikely to find these standards in developing countries.
There is also a risk in sharing jewellery that goes through the skin with other people.
Sexual intercourse
The risk of sexual transmission of hepatitis C is considered very low. The risk is higher for some sexual activities, especially where there is potential exposure to blood. This includes vaginal sex during menstruation or anal sex, with the associated risk of anal tears. Sex toys such as vibrators or dildos used during these activities are a potential risk. Oral sex, in the absence of blood is considered to be a low risk activity. In addition, the presence of some sexually transmitted infections may increase the risk. Unprotected sex, even once, with someone who is HIV-positive as well as hepatitis C-positive is a significant risk. The risk of hepatitis C transmission is much higher in the presence of HIV as well. Click here to read the results of a 10 year study into sexual transmission.
Steroids
Sharing any injecting equipment poses a risk of hepatitis C transmission, this includes equipment used to inject steroids to enhance fitness and physique.
Tattoos
The risks of tattooing are predominantly associated with re-used and unsterilised needles, although the virus has been found in tattooing ink also. The hygiene standards of tattoo parlours in the UK are uneven. Regulation is carried out by local authorities in some cases, (most of London) by licensing and in other cases using byelaws. These can vary from area to area but the DoH have produced a model set of byelaws (click here) that set out the standards that you ought to expect from a tattoing parlour. You are unlikely to find these standards in developing countries.
Tattooing with re-used equipment in high risk countries is a significant risk.
Vaccinations
Vaccination programmes in the developed world are considered to pose a very low risk of hepatitis C transmission. However, in the developing world, evidence exists that the same needles are sometimes used to vaccination numerous individuals, especially school children. The high incidence of hepatitis C in Egypt is largely attributed to mass public immunisation programmes.
