Viral Hepatitis Facts Sheet 2 - January 1998


Viral Hepatitis

Published by the Viral Hepatitis Prevention Board

Fact Sheet - 2 - January 1998

 

 

Universal HB immunization by 1997: where are we now?

Universal HB immunization by 1997

In the seven years since the Global Advisory Group of the Expanded Programme on Immunisation (EPI) set 1997 as the target for integrating hepatitis B (HB) vaccination into national immunisation programmes worldwide more than 90 countries have included routine hepatitis B infant and adolescent immunization in their national programmes. These countries represent roughly 40% of the world’s 145 million newborns annually and almost 60% of the world’s 350 million carriers1.

A global public health priority

Hepatitis B remains a major public health problem despite the widespread availability of safe and effective vaccines for almost 15 years. More than one-third of the world’s population are estimated to have been infected with the hepatitis B virus. Most have recovered, but there are around 350 million chronic carriers of the virus2. About a quarter of these carriers will develop serious liver disease, including chronic hepatitis, cirrhosis, and primary hepatocellular carcinoma. Nevertheless, universal vaccination is still being postponed in many countries. One reason is the weakness of our social commitment to preventative medicines and vaccines3; another is a lack of medical and public awareness; a third obstacle is thought to be financial.

Unexpectedly high HBV prevalence in eastern Europe and NIS

Countries are classified as having high (³ 8%), intermediate (2-8%), or low endemicity (< 2%) based on the prevalence of carriers of hepatitis B surface antigen in the general population.

In Europe the level of endemicity generally increases from north to south and from west to east. Unexpectedly high prevalence of hepatitis B carriage (5-12%) have been found in many parts of central and eastern Europe and the Newly Independent States (NIS) of the former Soviet Union. In the Central Asian Republics of the former Soviet Union and in some countries of central and eastern Europe, the estimated annual incidence of hepatitis B infection is 520 infections/100,000. These countries have intermediate or high endemicity. The remaining countries of central and eastern Europe have an estimated annual incidence of 130 infections/100,0004.

Immunization economically attractive in low-endemicity countries

Western Europe, North America and Australia have a low endemicity of hepatitis B virus, yet the incidence of new infections and the burden of acute and chronic disease place hepatitis B among the most important communicable diseases in those regions. Epidemiological data and economic evaluation show that universal hepatitis B vaccination is cost effective in countries with low endemicity and that it will control hepatitis B. However, some western European countries remain unconvinced that the burden of disease warrants the expense of universal vaccination and have as yet failed to implement hepatitis B immunization programmes.

Hepatitis B commonest cause of liver disease in Asia

Most countries in the Western Pacific region have adopted some hepatitis B immunization programme, usually infant immunization. National immunization programmes for hepatitis B are having a major impact, with carrier prevalence dropping to low endemicity in immunized children. Countries in the Indian subcontinent, however, have not yet begun routine hepatitis B immunization. HBV remains the commonest cause of chronic liver disease and hepatocellular carcinoma in all countries of the region, with the exception of Japan5,6.

Hepatitis B hyperendemic in Sub-Saharan Africa

HBV infection is hyperendemic in many parts of Africa, with decreases in carrier rates as a result of vaccination seen in only a few countries. Across Sub-Saharan Africa, about 75% of the population is exposed to HBV at some time in their lives and about 10 percent become chronic carriers. Approximately 230,000 deaths each year can be attributed to HBV-induced diseases, and 70% of hepatocellular carcinoma in blacks is related to HBV infection7. Despite the obvious need, many countries in Africa have not yet implemented universal infant vaccination.

In Latin America reservoir of HBV in Amazon

In Latin America, the Amazon Basin is an area of hyperendemicity; about 70% of the population show serological evidence of past or current HBV infection, and the prevalence of carriers is between 8-20%. Control and prevention programmes have been implemented in parts of Amazonia, and selective immunization programmes are also being carried out in other regions of Latin America, although only a few countries in the region have instituted universal infant immunization8.

Where are we now?

With the endorsement of the World Health Organization, the Global Advisory Group set 1997 as the target date for all countries to include hepatitis B vaccine in the national EPI. 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. What follows is a regional report on the progress made towards meeting these targets, and a discussion of the obstacles faced by regions which have yet to institute policies of universal immunisation.

 

Africa9

Virtually all countries in Sub-Saharan Africa are areas of high endemicity for hepatitis B, most with surface antigen carriers rates above seven percent. The need to introduce hepatitis B vaccine into the national immunization programmes is obvious, but at present the overall situation in Africa is as follows:

Asia and the Pacific Basin10

Over 75 percent of the world’s hepatitis B carriers live in the Asia-Pacific region. Even though 34 of the 36 countries in the region have hepatitis B vaccination policies, the programmes and levels of success vary. Where programmes have not been implemented successfully, the key constraints have been economic, organisational, technical and political.

An overview of the status of the programmes in the region highlights the challenges and obstacles to hepatitis B control:

What becomes clear when comparing the programmes in the region is that key to the success of any programme is political commitment to adequate funding of public sector programmes and delivery mechanisms in line with primary maternal and child healthcare. A decrease in cost through competitive tender has in some cases provided the springboard for commitment to national immunization.

It has also been shown that the addition of hepatitis B vaccine to the EPI can strengthen rather than detract from the overall vaccination programme. HB vaccination can actually be a vehicle for improving maternal and child healthcare in general, and it was demonstrated consistently that with the focus on hepatitis B immunization raised, rates of vaccination for other vaccines were raised as well.

Innovative vaccine delivery methods have sometimes been necessary to ensure good vaccine coverage: these include trials on a pre-filled, non-reusable, injection device for vaccine taken out of the cold chain and delivered to newborns in the home, and the use of combined DTP-HB vaccine.

Control of Hepatitis B in China12

Because of the high chronic carrier rate in China, control of HBV could be achieved only through universal immunization. Therefore, efforts to include hepatitis B vaccine in immunization programmes using the Chinese plasma-derived vaccine have been ongoing since 1986.

A programme of universal infant vaccination was begun in major cities, and screening of pregnant women and catch-up immunization of older children were later added. A two-prong immunization strategy was employed: infants whose mothers were not screened were given a standard vaccine dose, while infants born to HBsAg-seropositive women received a high vaccine dose or a standard dose plus HBIG. The city programmes have been successful, with coverage rates often above 90%. With urban programmes now well established, similar hepatitis B immunization programmes are now being implemented in rural areas. At present, approximately 20 million people are immunized per year in China.

During a nine-year follow-up to the immunization programme conducted in five provinces, over 25,000 blood samples from children up to nine years old were collected. In areas using a standard dose strategy, seropositivity for HBsAg dropped from 16.3% to between one and two percent. In areas using the high-dose strategy, the HBV carrier rate dropped from 8.8% to .41%. Anti-HB seroprevalence in vaccinees decreased from 96% in the first year to 68% in the ninth. In populations with a 90% vaccination rate, about 50% of unvaccinated children were also shown to be protected against HBV. Vaccine failure occurred almost exclusively in infants whose mothers had a high HBV-DNA content during pregnancy.

A high percentage of children in China are born at home, so it was key to the success of the immunization programme to develop vaccines that would remain effective when stored at room temperature. This was accomplished, making it possible for the first vaccine dose in the schedule to be delivered by midwives at home births.

Indian Ocean Programme of Immunization13

Since 1990, the Italian Institute for Prevention of Liver Disease has carried out a hepatitis B prevention programme in the Indian Ocean Islands of Comoros, Madagascar, Maldives, Mauritius, Seychelles, Sri Lanka and Zanzibar.

The purpose of the Indian Ocean Programme of Immunization (IOPI) is to:

Results of the ongoing study show that Comoros, Madagascar, Maldives, Zanzibar are islands of intermediate to high endemicity (HBsAg >4%); while Mauritius, Seychelles and Sri Lanka are low endemic islands (<1%). A high rate of HBe-antigen is present in pregnant women and their offspring, indicating that the main route of transmission in the area is vertical.

Strategies implemented for prevention of HBV infection include:

In high-endemic islands, vaccination of newborns has begun or been suggested. Selective vaccination of high-risk groups has been carried out or recommended for low-endemic islands. Seroconversion has been demonstrated in more than 90% of those immunised.

Central and Eastern Europe and the NIS14

The need for immunization programmes in areas of intermediate and high endemicity is undisputed. In the 25 countries in central and eastern Europe and the Newly Independent States (NIS) - many of which have high incidence rates of hepatitis B infection - only Albania, Bulgaria, Moldova, Poland, and Romania have included HBV in their national immunization programmes. The other countries have not yet begun mainly because of economic constraints.

In countries where hepatitis B vaccination has been introduced into national immunization programmes a substantial reduction in incidence rates can be seen. For instance, Bulgaria introduced mandatory universal immunization of all newborns and healthcare workers at high risk in 1991 and has subsequently implemented further measures in its programme to eliminate HBV by the year 2020. No deaths from HBV infection in infants were reported in 1993-1994 and no case was seen in an infant in 1995.

In Poland, immunization of newborns and infants of HBsAg-positive mothers was introduced in 1989; of health workers, medical students, nursery school children and laboratory technicians in 1990; of patients before operation in 1993; and for all newborns and infants in 1994-1996 (starting in districts with highest incidence).

Introduction of universal vaccination should save millions of lives in the countries of the region, particularly in those where HBV is hyperendemic. In Turkmenistan the Ministry of Health has conducted a pilot study with follow-up 4-6 years after a group of infants was vaccinated. Whereas in unvaccinated children HBsAg carrier rates of 7-17% were detected, the rate was 3% in the vaccinated 4-6-year-old children.

The Middle East15

The prevalence of HBsAg in the Middle East has been reported to vary from between four and 15 percent. Figures are relatively constant throughout age groups.

HBV marker prevalence shows that the virus is acquired early in life, usually at under five years of age. Most mothers in the region are e-antigen negative, unlike in Asia, reducing the importance of mother-child transmission. Instead, post-natal horizontal childhood transmission is the predominant means of transmission in the region, which accounts for high rates of chronic liver disease and carcinoma later in life. In particular, siblings of carriers have a carrier rate of 20 to 40 percent.

Cost-benefit analyses have shows that a post-natal immunization programme which integrates HB immunization into the national EPI programme would result in a 57% decrease in HBV carrier rate in the birth cohort and a sevenfold savings in direct healthcare costs. While a 60% decrease in mortality from HBV is also expected, this will not become apparent for 40-50 years. Perinatal programmes, on the other hand, would offer a twofold savings.

Universal HB vaccination programmes have been instituted in most Middle Eastern country. Vaccine uptake has been improved by education campaigns directed at families and healthcare workers, with a 95% vaccine uptake seen in populations exposed to the information campaigns, as compared to 65% in those populations not exposed to information campaigns.

Northern and Southern Europe

In Europe, a number of countries have instituted national policies to immunize infants or adolescents against hepatitis B. These include: France, Germany, Israel, Italy, Luxembourg, Portugal and Spain. The decision to include the HB vaccine in immunization programmes was supported by a variety of cost-effectiveness analyses. Belgium, Greece, Switzerland and Turkey have accepted recommendations that hepatitis B vaccine be included in the EPI. Most countries which use vaccine have started with adolescent immunization. Some have begun both adolescent and infant immunization. The United Kingdom, Ireland, the Netherlands and the Scandinavian countries have not introduced HB vaccine into the EPI - the argument being that the burden of disease does not warrant the expense of universal vaccination.

North America16

In the North American region Canada has instituted an adolescent programme of hepatitis B immunization; Mexico has vaccinated healthcare workers and high-risk groups since 1989 and is considering programme expansions; and the United States has incorporated hepatitis B immunization into the EPI.

In the United States the hepatitis B control and prevention programme includes a universal infant vaccination programme, a perinatal programme, and adolescent immunization. The goals of the infant vaccination programme are to:

The primary goal of the perinatal immunization programme in the United States is to reduce by the year 2000 the number of perinatal HBV infections by 80%, from the current 9,500 to 1,900. To achieve this, every state should have a law requiring HBsAg screening of all pregnant women by 1998, and by 2000, at least 90% of infants born to HBsAg-positive mothers should receive the first does of hepatitis B vaccine and hepatitis B immune globulin at birth and the remaining two doses by 6-8 months of age.

South America8

In the last six years, over 2 million people have received hepatitis B immunization in Latin America. A pilot study programme of childhood immunization in the hyperendemic area of the Amazon in Brazil began in 1988. In 1990, that programme - the first in Latin America - was incorporated into the National Programme of Immunization, and in 1992 it was expanded to include all healthcare workers and residents of the Amazon State.

Colombia has since 1991 been working to incorporate HBV vaccination into the EPI: vaccinating children up to 5 years old, the indigenous population and healthcare workers. In 1992, Argentina instituted a National Programme for vaccination of healthcare workers and plans are in the works to widen the programme to include screening of pregnant women and vaccination of high-risk populations. Uruguay and Chile are also promoting vaccination programmes, though not as part of EPI. In the South America region only Brazil, Columbia and Peru have decided to include hepatitis B in the EPI.

In Central America, Costa Rica is devising a hepatitis B vaccination programme, beginning with healthcare workers and high-risk groups (since 1989), and is planning on expanding the programme to include neonates of HBV-positive pregnant women, household contacts of HBV-positive carriers, and polytransfused and haemodyalisis patients. Panama, Honduras, El Salvador, Guatemala and recently Nicaragua have initiated vaccination of healthcare workers.

 

 

References

  1. Van Damme P, Kane MA, Meheus A on behalf of the Viral Hepatitis Prevention Board. Integration of hepatitis B vaccination into national immunisation programmes. BMJ 1997; 314: 1033-7.
  2. Kane MA, Clements J, Ju D, Hepatitis B. In: Jamison DT, Mosley WH, Measham AR, Bobadilla J, eds. Disease control priorities in developing countries. New York: Oxford University Press, 1993: 321-30.
  3. Francis DP. The public’s health unprotected - reversing a decade of underutilization of hepatitis B vaccine. JAMA 1995; 274: 1242-3.
  4. Roure C. Overview of epidemiology and disease burden of hepatitis B in the European Region. Vaccine 1995; 13 (suppl 1): S18-21.
  5. Gust ID. Current epidemiological trends of viral hepatitis in Australia and the Western Pacific region. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 45.
  6. Tandon BN, Tandon A, Acharya SK. Current epidemiological trends of viral hepatitis in Asia. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 44.
  7. Kew MC. Current epidemiological trends of viral hepatitis in Africa. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 45.
  8. Fay O, Fonseca JC, Martén A, et al. HBV vaccination in Latin America region. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 45.
  9. Ndumbe P, Maynard J, Goudeau A, Kane M. Control of Hepatitis B in Africa. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 22.
  10. Ruff T. Control of Hepatitis B in Asia and the Pacific Basin. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 22.
  11. Chang MH, Chen CJ, Lai MS, Hsu HM, Wu TC, Kong MS, Liang DC, et al. Universal hepatitis B vaccination in Taiwan and the incidence of hepatocellular carcinoma in children. NEJM 1997; 336: 26: 1855-59.
  12. Xu ZY, Cao HL, Lui CB, Wang SS, Yan TQ, Zhao SJ, Wu WS. Control of Hepatitis B in China. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 21.
  13. Da Villa G, Andjaparidze A, Elia S. Indian Ocean programme of immunization: progress and results. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 21.
  14. The Viral Hepatitis Prevention Board. Prevention and Control of hepatitis B in central and eastern Europe and the Newly Independent States. Report of a meeting organized by the Viral Hepatitis Prevention Board, the World Health Organization and the Centers for Disease Control and Prevention, Siofok, Hungary, October 6-9, 1996. Vaccine 1997; 15: 15: 1595-1597.
  15. Toukan A. Control of hepatitis B in the Middle East. Abstract volume ‘IX Triennial International Symposium on Viral Hepatitis and Liver Disease.’ Rome, Italy, April 21-25, 1996. 22.
  16. Centers for Disease Control and Prevention. Hepatitis Surveillance: New Horizons. Evaluating the effectiveness of the programmes to prevent hepatitis B virus (HBV) transmission in the United States. Report Number 56, 1996.

 

 

 

 

 

Regional status report on hepatitis B immunization and control programmes

 

 

With the endorsement of the World Health Organization, the Global Advisory Group set 1997 as the target date for all countries to include hepatitis B vaccine in the national EPI. The World Health Assembly added a disease reduction target, calling for an 80% decrease in new HBV child carriers by 2001.