Epidemiology - Hepatitis C Virus

Epidemiology

Hepatitis C is prevalent worldwide.

◗ Geographical distribution

More than 3% of world’s population is infected with HCV. Worldwide 170 million people are estimated to be infected with HCV. It is the most important cause of parenteral NANBH worldwide. The prevalence rates are reported to be as high as 22% in Egypt due to use of parenteral antischistosomal therapy. The prevalence rates in healthy blood donors are also equally high. Hepatitis C virus is highly prevalent in central Europe, Middle East, Spain, Italy, and Japan.

◗ Reservoir, source, and transmission of infection

Hepatitis C is exclusively a human disease. Patients who are infected with the virus are the important reservoir of infection. Blood or blood products and also organs of infected patients are the major sources of infection. Hepatitis C can be transmitted by following methods:

Blood transfusion: Blood transfusion is the most importantroute of transmission of HCV. The current risk of transfusion-derived HCV is estimated to be one case in every 100,000 units transfused.

Parenteral transmission: HCV is transmitted parenterally(a) through transfusion of infected blood or blood products, (b) transplantation of organs from infected donors, and (c) also by sharing of contaminated needles among intravenous drug users. The use of intravenous drugs is most important risk factor responsible for around 50% of both acute and chronic infections.

Sexual transmission: Sexual transmission is believed to beresponsible for approximately 20% of cases of hepatitis C. The presence of coexisting sexually transmitted disease, such as HIV, appears to increase the risk of transmission.

Perinatal transmission: Perinatal transmission is possible andis observed in fewer than 5% of children born to HCV-infected mothers. The risk of perinatal transmission of HCV is higher in children born to mothers who are coinfected with HCV and HIV.

Other methods of transmission: Hemodialysis, tattooing,body piercing, and acupuncture with unsterile equipments are other, but less frequent, means of transmission of HCV. Needle stick injury among healthcare workers who are exposed to infected blood accounts for nearly 4% of new infections. The possibility of acquiring HCV after needle stick injury involving an infected patient appears to range from 0% to 7%.