Hepatitis B Vaccination: What Are the Current International Recommendations?

HBV seroprevalence after 25 years of universal mass vaccination and management of non-responders to the anti-Hepatitis B vaccine: An Italian study among medical students

According to international guidelines, healthcare workers and medical students immunized against HBV are periodically tested for anti-HBs IgG. Subjects who show an anti-HBs titre <10 mUI/mL must receive additional vaccine doses to induce a measurable antibody response. This study aimed to evaluate the long-time immunogenicity of anti-hepatitis B vaccination in a sample of medical students and residents of the University of Bari who attended the Hygiene Department for biological risk assessment (April 2014-June 2017). The strategy for the management of nonresponder subjects was evaluated. A total of 3676 students and residents were invited for testing according to a standardized protocol. Anti-HBs IgG was tested for in 3140 (85.4%) subjects: 1174/3140 (37.7%) subjects were negative. 14.6% (128/808) of subjects who received the vaccine during their 12th year of life and 45.8% (1056/2305) of subjects immunized during the first year of life (P < 0.0001) were negative. 1005/1174 (85.6%) seronegative subjects received a booster dose, and 903/1005 (89.9%) were tested for anti-HBs 1 month after the booster dose: 82/903 (9.1%) subjects were still negative. Of these, 56/82 (68.3%) received 2 additional doses of vaccine and 52/56 (92.9%) were tested 1 month after the third dose: 50/52 subjects (96.2%) developed a positive titre. In conclusion, several medical students, immunized at birth or at young age against HBV, did not develop protective titres against the virus. Our management strategy (booster retest; for negative subjects, 2 doses and retest) seems consistent with the purpose of evidencing immunological memory.

Antibody persistence and immune memory elicited by combined hepatitis A and B vaccination in older adults

Response to hepatitis A and B vaccines has been reported to decline with age. This open, prospective, single-site study examined the long-term response to the combined hepatitis A/B vaccine Twinrix in 98 primary responders aged 45-67 years. Levels of antibody against hepatitis A virus (HAV) and hepatitis B surface antigen (HBs) were tested 30 months after initial vaccination. At this stage, all participants remained seropositive for anti-HAV and 70% for anti-HBs. A booster vaccination was offered to those who had responded to the first vaccination but then lost protective levels of anti-HBs. An anamnestic response was observed in all cases.

Vaccination against hepatitis B: current challenges for Asian countries and future directions

AIMS

To review the current status of hepatitis B immunization programmes as well as future issues concerning hepatitis B immunization in Asian countries.

METHODS

Pertinent literature was identified via in-house and MEDLINE (1980-99) searches and references cited in published articles. Articles within the Proceedings of the IX Triennial International Symposium on Viral Hepatitis and Liver Disease provided valuable state-of-the-art resource data.

RESULTS

Chronic hepatitis B infection is responsible for 75-90% of primary hepatocellular carcinoma, one of the 10 most common cancers worldwide. Hepatitis B and its chronic sequelae can potentially be eradicated through vaccines that have been shown to be 95-99% efficacious in preventing development of the disease or the carrier state in immunized infants. Approximately 75% of the world's hepatitis B carriers live in Asian countries wherein wide variations in immunization strategies exist. Vaccination programmes in hyperendemic Asian countries have elicited decreases in the incidence of acute and chronic infections as well as a decrease in chronic carriers in the unvaccinated population. Decreases in the incidence of hepatocellular carcinoma have been recorded in Taiwan and Singapore after at least 10 years of universal hepatitis B immunization programmes.

CONCLUSIONS

In Asian countries currently without nationwide hepatitis B programmes, utilization of the existing vaccination infrastructure for administration of other World Health Organization Expanded Programme on Immunization vaccines will provide the most economical and efficient means of administration of the hepatitis B vaccine.

Hepatitis B epidemiology in Asia, the Middle East and Africa

Asia and Africa have previously been classified as areas of high endemicity for hepatitis B virus (HBV), but in some countries highly effective vaccination programmes have shifted this pattern towards intermediate or low endemicity. Thus, China is now the only country in Asia where HBV endemicity is high. Countries with intermediate endemicity include India, Korea, the Philippines, Taiwan and Thailand, and those with low endemicity include Japan, Pakistan, Bangladesh, Singapore, Sri Lanka and Malaysia. Most countries in Africa have high HBV endemicity, with the exceptions of Tunisia and Morocco, which have intermediate endemicity. Zambia has borderline intermediate/high endemicity. In the Middle East, Bahrain, Iran, Israel and Kuwait are areas of low endemicity, Cyprus, Iraq and the United Arab Emirates have intermediate endemicity, and Egypt, Jordan, Oman, Palestine, Yemen and Saudi Arabia have high endemicity. All of these Middle East countries reach a large proportion of their population with hepatitis B vaccination, which is reducing the infection rate, particularly in Saudi Arabia. The vaccination programme in Taiwan has also greatly reduced the HBV infection rate. Future vaccination programmes must take into account the mode of transmission of HBV, the healthcare infrastructure to deliver vaccination, and the socioeconomic and political factors in each individual country, to determine the most cost-effective way of infection control.

Over a decade of experience with a yeast recombinant hepatitis B vaccine

Experience with the yeast recombinant hepatitis B vaccine Engerix-B now exceeds 10 years. We reviewed published studies on this vaccine. These show the vaccine to be safe, causing mostly only minor local symptoms and to be highly immunogenic both in monitored clinical trials and under field conditions. Engerix-B consistently elicits high geometric mean antibody titres and a high protective efficacy has been established in three groups at high-risk of hepatitis B infection, homosexual men, institutionalised mentally handicapped subjects and neonates of chronic carrier mothers. The profile of the recombinant hepatitis B vaccine in certain high-risk groups and immuno compromised people is discussed. Finally we present updated post marketing surveillance data based on 496 million distributed doses of vaccine.

Immunisation strategies for viral diseases in developing countries

In just under a quarter of a century, the Expanded Programme on Immunisation has been associated with an increase in infant immunisation coverage from around 5% to 80%, and the prevention of at least 3 million deaths annually, at very low cost. The global target of poliomyelitis eradication by the year 2000 appears feasible. Measles is the next likely target for eradication via immunisation, through 'catch-up', 'keep up' and 'follow-up' strategies which have proven highly effective in the Americas. Yet much needs to be done in order to extend readily achievable immunisation benefits equitably to all the world's people and to realise the potential of existing and soon to be available vaccines for disease control and eradication, as experience with yellow fever and hepatitis B vaccines demonstrates. Unsafe injection practices are widespread, have received inadequate attention, and cause a substantial global burden of blood-borne infections. The risk of increasing global inequity in immunisation highlights the centrality of resource allocation priorities in determining the extent to which the benefits of immunisation will be realised, particularly for new vaccines which are significantly more costly than established EPI vaccines. WHO/UNICEF strategies to target more effectively immunisation support to the neediest countries, to prioritise new vaccines, and to target carefully vaccine procurement and encourage sharply tiered vaccine pricing support both equity and sustainability. However, increasing the resources available to immunisation is vital and requires powerful advocacy on public health, moral, cost-effectiveness and legal grounds. More appropriate resource allocation priorities could readily provide the means necessary to address both technical and operational immunisation challenges.

Juvenile offenders and hepatitis B: risk, vaccine uptake and vaccination status

OBJECTIVE

To determine the hepatitis B vaccination status of juvenile offenders in a custodial setting, their perceived risk of hepatitis B infection, and factors influencing vaccine uptake.

DESIGN

130 males aged 14-17 years resident at the Melbourne Juvenile Justice Centre for at least one week between mid-January and mid-December 1996 were invited to participate; 90 (69%) completed a doctor-administered questionnaire, and blood for serological testing was obtained from 83 of these participants.

MAIN OUTCOME MEASURES

Whether hepatitis B vaccine had been offered; whether hepatitis B vaccine had been given; the presence of antibodies to hepatitis B and C; risk factors and self-perceived risk of hepatitis B.

RESULTS

About a quarter of participants (22/83) had protective levels of antibody to hepatitis B surface antigen (anti-HBs). Forty (44%) participants reported having been offered hepatitis B vaccine; they were more likely to be vaccinated and have protective levels of anti-HBs. Perceived risk for bloodborne virus infection was low, although two-thirds of participants were at high risk of hepatitis B infection. On serological testing, 6.4% (5/78) were positive for antibody to hepatitis B core antigen (anti-HBc), and a further 2.6% (2) had equivocal antibody levels. Of the 71 who were negative for anti-HBc, 51 (71.8%) were negative for anti-HBs.

CONCLUSIONS

The targeted hepatitis B vaccination program has not adequately protected this group at high lifetime risk of hepatitis B. Failure to deliver vaccine may reflect lack of contact with healthcare services, oversight in offering vaccine and reluctance of youth to participate in preventive healthcare measures, often through not seeing themselves to be at risk. Universal approaches to vaccination may be more successful in vaccinating this group.

Immunogenicity and reactogenicity of a combined hepatitis A-hepatitis B vaccine in adolescents

OBJECTIVE

To evaluate the immunogenicity and reactogenicity of two lots of a combined hepatitis A-hepatitis B vaccine (HAV, HBV) in healthy 15 to 18 year olds.

DESIGN

This was a double-blind, randomized clinical study. Vaccine was administered into the deltoid at 0, 1, and 6 months. Immunogenicity was assessed by anti-HAV and anti-HBs antibody levels at 2, 6, and 7 months after the first vaccine dose. Reactogenicity was assessed through use of 3-day diary cards following each vaccination, plus recording other unsolicited reactions.

RESULTS

A total of 160 adolescents were vaccinated; 155 who were seronegative for hepatitis A and B at baseline and who completed the study were included in the immunogenicity analysis. The vaccine was well tolerated; most side effects were local, of low intensity and short duration. Good immunogenicity was determined by antibody titers. High rates of seropositivity (99.4%) were achieved after two doses against HAV, and after three doses for anti-HBs (seroprotection = 98.7%).

CONCLUSIONS

This combination vaccine will be useful for immunizing selected high-risk groups in developed countries. In countries where endemicity is low for both diseases, targeting students prior to risk of acquisition would be a feasible preventive strategy.

Hepatitis B immunisation rates among infants in ethnic groups with high prevalences of hepatitis B surface antigen carriers

To determine hepatitis B immunisation rates in infants from ethnic groups with hepatitis B surface antigen chronic carrier prevalence over 5 per cent, a questionnaire was sent to all Maternal and Child Health Centres in Victoria, requesting information on the hepatitis B and diphtheria-tetanus-pertussis (DTP) or combined diphtheria-tetanus (CDT) immunisation status for all infants born between 1 July 1992 and 30 June 1993 and at risk of hepatitis B infection because of maternal ethnicity. We received data on 3611 of 5744 infants (62.9 per cent) in targeted ethnic groups. Of these, 12.8 per cent had not received hepatitis B vaccine, and 81.6 per cent, 76.8 per cent and 64.0 per cent had received at least one, two and three doses respectively, while 84 per cent had received at least three doses of DTP vaccine and/or CDT vaccine. Coverage with DTP or CDT was higher than for hepatitis B vaccine (P < 0.001), and coverage was better in areas with a higher percentage of infants in high-prevalence ethnic groups (P < 0.001). Changes in the program in Victoria in terms of timing of the first dose of vaccine plus greater attention to follow-up may lead to improved hepatitis B immunisation rates among infants in targeted ethnic groups. Adoption of universal infant hepatitis B immunisation, by increasing familiarity with hepatitis B vaccine, is likely to be the best way to increase immunisation coverage for these infants.

Epidemiology of hepatitis B infection in the Western Pacific and South East Asia

The Western Pacific and South East Asia regions are the largest and most populous of the six World Health Organisation regions and include more than 40 countries. More than 75% of the world's estimated 350 million carriers are located here. The region has therefore provided many insights into the epidemiology, natural history, and control of hepatitis B infection and has been home to the first national control programmes. Hepatitis B is hyperendemic in most countries of the region, with carrier rates ranging from 5-35% except in Australia, New Zealand, and Japan, where the mean carrier rate is less than 2%. Patterns of infection vary considerably from country to country, city to city, and even village to village, and can change with time. Most infections are acquired early in childhood or in early adult life. A variety of control measures are in place and many countries in the region have introduced widespread or universal childhood immunisation policies with significant success. While it is theoretically possible that hepatitis B infection could be eradicated by universal childhood immunisation, there are several biological and practical issues that make this extremely difficult, suggesting that, for the foreseeable future, control may be a more realisable goal.