Hepatitis B infections are among the most common infectious diseases worldwide. The disease can become chronic, and is one of the most important causes of severe diseases such as liver cancer. In the scope of an international study funded by the World Health Organization, scientists from the Helmholtz Centre for Infection Research (HZI) in Braunschweig determined how often the chronic infection occurs in different countries and how many people of the general population are affected. They noted strong differences between different countries. Their results are published in the scientific journal, The Lancet.
Although an effective vaccine is available against the hepatitis B virus, many people throughout the world suffer from morbidity and mortality due to severe liver diseases caused by chronic hepatitis B infection. And the number of those individuals being infected is even larger. "According to our estimates, approximately 248 million people worldwide live with chronic hepatitis B virus infection, with a disproportionally high burden in some countries," says Dr Jördis J. Ott, who is a scientist at the Epidemiology department of the HZI.
Ott and her colleagues assessed the prevalence of chronic hepatitis B virus infection for 141 countries on the basis of all relevant data published on this topic. "While the fraction of chronically infected people in the general population is only 0.01 per cent in some countries, over 20% are infected in other countries according to our results," says Ott. Especially in parts of Africa and in lower-income countries of other geographical regions, chronic hepatitis B virus infection is a major health issue.
The scientists also looked for evidence of how the prevalence of hepatitis B infections changed between the study periods 1957-1989 and 1990-2013. Decreases were obvious in most countries and on a global average. Although an association with vaccine implementation following the universal vaccine recommendation of the World Health Organization in 1992 appears likely, reasons for the changes still need to be investigated in further studies.
Despite the availability of both vaccines and treatment options, the results highlight that chronic hepatitis B virus infections continue to be an important global health problem, mainly in countries which generally face a large number of infectious diseases and in which infection protection measures may lack. "This is the most comprehensive systematic analysis on this issue to date and the results clearly demonstrate the global health burden associated with hepatitis B," says Prof Dirk Heinz, who is the Scientific Director of the HZI.
Prof Gérard Krause, who is the head of the Epidemiology department, also sees an immediate need for action to result from the study: "We urgently need to work on making the prevention measures become more effective. Even more so since the problem is expected to be even more serious in high risk groups, such as injecting drug users, to name just one example," says Krause.
This calls for concrete action. "For example, it is very important to vaccinate newborns that are under risk in order to prevent the disease from becoming chronic," says Ott. Moreover, available options for diagnosis and treatment need to be made accessible to a broader range of the populations and basic prevention measures, such as the safety of blood products, need to be implemented on a global scale.
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