Viral Hepatitis Facts Sheet 1 - January 1996

FACT SHEET VHPB/ 1996/1

TARGETS:

In 1991, the Global Advisory Group of EPI (Expanded Programme on Immunization) set 1997 as the target for integrating the hepatitis B vaccination into national immunisation programmes worldwide. The group recommended strategies for implementation and delivery that vary according to epidemiology: advocating integration of the vaccine into immunisation programmes by 1995 in countries with a HBV carrier prevalence of eight percent or higher; and setting 1997 as the target date for all other countries. The World Health Organisation endorsed the recommendation in May 1992; and the World Health Assembly added a disease reduction target for hepatitis B in 1994, calling for an 80 percent decrease in new HBV child carriers by 2001.

EUROPE:

Although Europe is considered a region of low endemicity for the HB virus, the prevalence of carriers, the incidence of new cases, and the burden of acute and chronic disease place hepatitis B among the most serious communicable diseases in the region. In terms of the estimated number of serious sequelae and deaths, the HB virus poses a more serious health risk than many other vaccine-preventable infections. The burden of disease highlights the necessity for action in eradicating hepatitis B as a community-acquired risk.

Presently, more than 75 countries have national policies including the routine vaccination of infants and/or adolescents against hepatitis B. These countries are home to approximately 37 percent of the world's 145 million newborns, but almost 60 percent of the world's 350 million carriers.

In Europe, a number of countries have instituted national policies to immunise infants or adolescents against hepatitis B. These include: Albania, Bulgaria, France, Germany, Luxemburg, Italy, Moldova, Portugal, Romania and Spain (see map). The decision to include the HB vaccine in immunisation programmes was supported by a variety of cost-effectiveness analyses.

The universal immunisation programmes in Spain and Italy have proven to be highly successful, and offer exemplary models for other countries. Whether infant and/or adolescent immunization should be implemented, depends on country-specific epidemiology and existing delivery systems.

In several Northern European countries decision makers are not convinced that the disease burden of hepatitis B justifies the expense of universal vaccination. Numerous cost-effectiveness studies performed for low-endemic countries, however, indicate that universal vaccination against hepatitis B is economically advantageous and health policy makers should carefully consider these studies when formulating policy.

RECOMMENDATIONS:

The Viral Hepatitis Prevention Board (VHPB) - an independent, international, multi-disciplinary group of experts - endorses the recommendation of EPI, and reiterates the advisory group's advice that all countries should meet the 1997 target for universal HB vaccination to improve the control and prevention of hepatitis B. In addition, the VHPB formulated the following recommendations at its recent meeting in Genoa, November 7 and 8, 1995.

1. The VHPB reaffirms its endorsement of the 1991 recommendation put forward by the EPI Global Advisory Group of WHO - a recommendation endorsed by the World Health Assembly in May, 1992. Accordingly, the hepatitis B vaccine should be integrated into all national immunisation programmes by 1997, regardless of the prevalence of the infection.

2. The VHPB supports efforts to add the hepatitis B vaccination to existing infant and adolescent immunisation programmes. Hepatitis B vaccines can and should be integrated into any existing schedule. In addition, combination vaccines would be useful in hepatitis B control programmes. Existing recommendations for vaccinating individuals identified as having a high risk of contracting hepatitis B should be maintained to provide protection on an individual basis. Vaccinating only high-risk groups against hepatitis B, however, will not significantly control hepatitis B infection in the population at large.

3. The VHPB advocates the development and use of combination vaccines which contain a hepatitis B component. These vaccines require fewer injections, thus making them more acceptable to the public and the health care providers and representing savings on syringes, storage, transportation, record keeping and training. In adddition, it could possibly reduce the number of medical visits required. The implementation of universal hepatitis B immunisation, however, should not be delayed until combined vaccines are available.

4. The VHPB seeks to raise the awareness of health care providers about the need for hepatitis B immunisation, both for themselves and for their patients. The board also realises the importance of understanding the attitudes, beliefs and behaviours of health care providers, health policy makers and the general public when working to improve the success of universal hepatitis B vaccination programmes.

5. There are few absolute contraindications to vaccination. Still, withholding vaccination for inappropriate contraindications has been identified as an important cause of under-immunisation. For hepatitis B, only severe reactions to previous doses, hyper-sensitivity to one of the vaccine components, and fever above 38.5oC are considered contraindications.

KEY STATISTICS:

Hepatitis B is one of the world's most common and serious infectious diseases. It is estimated that more than one third of the world's population has been infected with the hepatitis B virus. Approximately 350 million people - or five percent of the population - are chronic carriers of the HB virus. Nearly 25 percent of all carriers will develop serious liver diseases such as chronic hepatitis, cirrhosis and primary hepatocellular carcinoma. According to WHO estimates, hepatitis B infection causes more than one million deaths every year.

TRANSMISSION:

Currently, there are four recognised modes of transmission:

1. transmission from mother to child at birth (perinatal);

2. transmission from contact with an infected person (horizontal);

3. transmission through sexual contact;

4. transmission through parenteral exposure to blood or other infected fluids.

Three epidemiological patterns of the hepatitis B virus are represented in Europe: high endemicity in some parts of Eastern and Central Europe; intermediate endemicity in Southern Europe; and low endemicity in Western Europe.

Although Europe is considered a region of low endemicity for the HB virus, the burden of acute and chronic disease place hepatitis B among the most serious communicable diseases in the region. In most European countries, procedures for mandatory notification of HB infections are not well established. Consequently, the number of cases reported each year is far below the actual incidence of infection.

Approximately 160,000 cases of acute hepatitis B infections are reported each year in the WHO European region1. Because of under-reporting, and because at least half of all HB infections occur asymptomatically, WHO estimates the actual number of people infected with hepatitis B yearly to be 950,000. Of these, 90,000 will become chronic HBV carriers and 24,000 will die from the consequences of chronic disease, cirrhosis and primary liver cancer (see figure).

In the Central Asian Republics of the former USSR2 and in some countries of Eastern Europe3, hepatitis B is a serious threat to community health, with an estimated annual incidence of 520 HBV infections per 100,000 people. Some of these countries are classified as areas of high endemicity, which is characterised by a carrier rate of eight percent or more and an overall HBV prevalence of 70 percent or more (see table). The remaining countries in the Eastern European region have an estimated annual rate of infection of 130 per 100,000 people, making them areas of intermediate endemicity.

(adapted from Roure C. Vaccine, 1995; 13(suppl.1): S18-S21; and Van Damme P., et al. Vaccine 1995; 13(suppl.1): S54-S57).

Figure: Annual estimated outcome of HBV infection in the WHO European region.

(adapted from: Van Damme P.,et al. Vaccine, 1995; 13(suppl.1): S54-S57).

In Southern Europe4 the prevalence of HB carriers varies between one and five percent (table), while the lifetime risk of HB has been estimated at between 10 and 20 percent. The annual rate of HB infections is approximately 37 per 100,000. In this region, chronic liver disease is a leading cause of death, accounting for 34 cases per 100,000 annually.

Most carriers are infected early in life. Because the prevalence of HBeAg among carriers' mothers is low, it is horizontal rather than perinatal transmission that plays the major role in HB epidemiology in Southern Europe.

In Western Europe the HBsAg carrier rate is between 0.1 and 0.5 percent; the overall HBV markers prevalence rate varies from five to 10 percent (see table). Acute hepatitis B is more common among young adults, with a peak incidence of 20 to 30 acute cases per 100,000 in the 20 to 30 age group.

As far as risk factors could be traced, sexual transmission prevails, accounting for at least 40 percent of all cases. IVDU accounts for 10 to 25 percent of hepatitis B cases of identified origin.

Northern Europe5 shows the lowest rate of hepatitis B infection: the HBsAg carrier rate and the overall prevalence of HBV are estimated at less than 0.1 percent and less than 0.5 percent, respectively (see table). The annual incidence rate of HBV infections is approximately eight per 100,000.

1 The WHO European region has a total population of 839 million inhabitants

2 Azerbaijan, Kazakstan, Kyrgyzstan, Tadjikistan, Turkmenistan and Uzbekistan

3 Albania, Bulgaria, Moldova and Romania

4 Greece, Italy, Portugal and Spain

5 Denmark, Iceland, Ireland, Finland, Norway, Sweden, and United Kingdom

Comments, feedback and suggestions are encouraged. Please send mail to
Pierre Van Damme