By Dr Ananya Mandal, MD
Hepatitis C infection is one of the most widely spread infections worldwide and affects 3% of the world population.
The World Health Organization (WHO) also estimates that there are 170 million of carriers of hepatitis C who carry the potential to spread the infection and go on to develop liver cirrhosis and liver cancer.
As many as 2 to 4 million persons may be chronically infected in the United States, 5 to 10 million in Europe.
About 150 000 new cases occur annually in the US and in Western Europe, and about 350 000 in Japan.
Most European countries have a prevalence of between 0.5 and 2%.
Of these infected cases worldwide, about 25% show no symptoms but 60 to 80% may progress to chronic liver disease. 20% of these develop liver cirrhosis and 5%-7% of patients may ultimately die of the consequences of the infection including liver cancer.
Hepatitis C from blood transfusions
Before screening for hepatitis C of donors of blood, tissues and organs came into practice in 1992, hepatitis C remained a common cause of blood transfusion related hepatitis C.
In the United States alone 90% of all hepatitis C infections were due to contaminated blood transfusions.
Before the 1970’s around 7% of transfusion recipients developed hepatitis (that was not hepatitis A or B) and up to 1% of blood units contained the responsible virus.
After screening blood and other donor products came into being the numbers declined by nearly 100%.
Hepatitis C in the USA
In the USA at present hepatitis C forms around 20% of acute viral hepatitis cases and less than 5% of these are associated with blood transfusion.
The highest risk group remains injecting drug users and haemophilia patients forming 98% of all infections.
The prevalence varies among patients receiving haemodialysis for kidney damage and is low among homosexual men, healthcare workers, heterosexuals with multiple sexual partners and family contacts of hepatitis C infected persons.
The prevalence is lowest among volunteer blood donors (0.3%-0.5%). In the general population the prevalence is between 0.2% and 18%.
Worldwide hepatitis C prevalence
Worldwide, areas with high prevalence of the infection include countries in the Far East, Mediterranean countries and some countries in Africa and Eastern Europe.
Egypt for example has a high prevalence of the infection and has high disease and death rates due to chronic liver disease, liver cirrhosis and liver cancer caused by hepatitis C infection.
Approximately 20% of Egyptian blood donors test positive for hepatitis C antibodies.
Clusters of prevalence are also seen among some communities in Italy as well. The prevalence of anti-hepatitis C virus is greater than 5% in some communities.
The rates are higher among those over 60 and this is attributed to the early use of glass syringes for medical purposes rather than disposable syringes that are being used after 1970’s.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)