Press Release WHO/36
1 May 1998
HEPATITIS C: 170 MILLION INFECTED WORLDWIDE AND STILL NO VACCINE
The current global pandemic of hepatitis C is a major public health problem. Prevalences of 0.5% to greater than 10% have been found in population samples around the world* , experts heard during a meeting at World Health Organization (WHO) headquarters from 27-29 April. More than 170 million people worldwide are now estimated to suffer from the disease, said Dr Daniel Lavanchy of WHO's Division of Emerging and other Communicable Diseases Surveillance and Control (EMC).
Moreover, information concerning the link between infectious diseases such as hepatitis C and cancer is growing: it is now estimated that about 80% of acutely infected patients progress to chronic hepatitis, that about 20% of these chronic infections develop cirrhosis, and that 1% to 5% of cirrhotic individuals will develop hepatocellular carcinoma (cancer of the liver) during the next 10 years.
And the problem continues to worsen, especially in developing countries. New infections continue to occur because of unscreened blood transfusions, failure to sterilize hospital and injection equipment and, in some instances, unprotected sexual intercourse. It is important to halt the spread of the disease, the experts emphasized.
No vaccine is available yet, although research continues and preliminary clinical trials of an experimental vaccine are in progress. Active immunization against hepatitis C may be possible early in the next century but, in the meantime, preventing the spread of the disease must be paramount.
Groups considered especially at risk should be priority targets for prevention efforts, the experts concluded. In both developed and developing countries, high-risk groups include intravenous drug users, recipients of unscreened blood, haemophiliacs, dialysis patients and the sexually promiscuous who engage in unprotected sex. In developing countries, people who take part in traditional scarification and circumcision practices are also at risk if they use unhygienic or re-used tools for these operations.
Prevention efforts should include screening of all blood donors and organ donors worldwide, informing health workers on the risk and means of transmitting hepatitis C, educating schoolchildren and others in the community about the disease, its effects and means of stopping its spread, the experts agreed.
Other pressing needs are for more accurate information on how many people have been infected with hepatitis C virus and the costs versus the benefits of different types of prevention programmes. Worldwide data on new and chronic infection are suboptimal or incomplete; most data comes from blood donor studies or other limited epidemiological investigations, and such data cannot be readily extrapolated to entire populations.
There is not yet an adequate explanation of how or why some virus or host factors will lead the carrier of the disease to develop cirrhosis and liver cancer, while others do not, the experts said, although better knowledge of the epidemiology of the disease would enable countries to prioritize their preventive measures and make the most appropriate use of available resources.
The causative agent of hepatitis C was only identified in 1989**. Its identification and characterization led to the understanding of its primary role in post-transfusion hepatitis and its tendency to induce persistent infection: percutaneous (via the skin) exposure to blood is the predominant mode of transmission of hepatitis C. In developed countries it is estimated that 90% of cases of hepatitis C infection are in current and former intravenous drug users and those with a history of transfusion of unscreened blood or blood products, such as haemophiliacs. In developing countries, it is believed that unsterile injections and unscreened blood are the predominant modes of transmission.
* See WHO Weekly Epidemiological Record, issues of 7 March and 14 November 1997, for individual country prevalence.
** For further details on Hepatitis C, see WHO Fact Sheet No. 164
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