Evaluation of the hepatitis B antenatal screening and neonatal immunization program in Amsterdam, 1993-1998

Immunoprophylaxis failure and vaccine response in infants born to mothers with chronic hepatitis B infection in Djibouti

BACKGROUND

In endemic areas, vertical transmission of hepatitis B virus (HBV) remains a major source of the global reservoir of infected people. Eliminating mother-to-child transmission (MTCT) of HBV is at the heart of World Health Organization's goal of reducing the incidence of HBV in children to less than 0.1% by 2030. Universal screening for hepatitis B during pregnancy and neonatal vaccination are the main preventive measures.

AIM

To evaluate the efficacy of HBV vaccination combined with one dose of immunoglobulin in children born to hepatitis B surface antigen (HBsAg)-positive mothers in Djibouti city.

METHODS

We conducted a study in a prospective cohort of HBsAg-positive pregnant women and their infants. The study ran from January 2021 to May 2022, and infants were followed up to 7 mo of age. HBV serological markers and viral load in pregnant women were measured using aVidas microparticle enzyme-linked immunosorbent assay (Biomérieux, Paris, France) and the automated Amplix platform (Biosynex, Strasbourg, France). All infants received hepatitis B immunoglobulin and were vaccinated against HBV at birth. These infants were closely monitored to assess their seroprotective response and for failure of immunoprophylaxis. Simple logistic regression was also used to identify risk factors associated with immunoprophylaxis failure and poor vaccine response. All statistical analyses were performed with version 4.0.1 of the R software.

RESULTS

Of the 50 pregnant women recruited, the median age was 31 years, ranging from 18 years to 41 years. The MTCT rate in this cohort was 4% (2/50) in HBsAg-positive women and 67% (2/3) in hepatitis B e antigen-positive women with a viral load > 200000 IU/mL. Of the 48 infants who did not fail immunoprophylaxis, 8 (16%) became poor responders (anti-HB < 100 mIU/mL) after HBV vaccination and hepatitis B immunoglobulin, while 40 (84%) infants achieved a good level of seroprotection (anti-HB > 100 mIU/mL). Factors associated with this failure of immunoprophylaxis were maternal HBV DNA levels (> 200000 IU/mL) and hepatitis B e antigen-positive status (odds ratio = 158, 95% confidence interval: 5.05-4958, P < 0.01). Birth weight < 2500 g was associated with a poor immune response to vaccination (odds ratio = 34, 95% confidence interval: 3.01-383.86, P < 0.01).

CONCLUSION

Despite a failure rate of immunoprophylaxis higher than the World Health Organization target, this study showed that the combination of immunoglobulin and HBV vaccine was effective in preventing MTCT of HBV. Therefore, further studies are needed to better understand the challenges associated with immunoprophylaxis failure in infants in Djibouti city.

Uptake of perinatal immunoprophylaxis for infants born to women with a record of hepatitis B in Victoria (2009-2017)

BACKGROUND

Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) remains one of the leading causes of transmission worldwide. An estimated 90 % of infants who are exposed to HBV and do not receive appropriate post exposure immunoprophylaxis will go on to develop chronic hepatitis B (CHB). In Australia, universal birth dose vaccination was adopted in 2000 and universal antenatal screening for hepatitis B was introduced in the 1990 s, however up to 10 % of women may have missed screening. There is no coordinated care or data collection that systematically reports the access to interventions to prevent mother-to-child transmission (PMTCT) for women with CHB. Therefore, the incidence rate of MTCT is unknown.

METHODS

We conducted retrospective data linkage of perinatal records, public health notification and hospital admission data to identify women with a record of HBV infection who had given birth to a live infant(s) in Victoria between 2009 and 2017. We assessed uptake of birth dose vaccination and hepatitis B immunoglobulin (HBIG) and explored factors associated with administration of birth dose recorded as administered within 7 days.

RESULTS

Among 690,052 live births, 6118 births (0.90 %) were linked to 4196 women with a record of HBV infection. 89.4 % of all Victorian infants (n = 616,879), and 96.8 % of infants linked to women with a positive record of CHB (n = 5,925) received birth dose within 7 days. Infants born in private hospitals had reduced odds of receiving birth dose when compared to public hospitals births (Victorian population, aOR = 0.67, 95 %CI = 0.66, 0.69; CHB linked records aOR = 0.17, 95 %CI = 0.11, 0.25). Of the 6118 infants linked to a positive maternal record of CHB, discrepant recording of maternal CHB status between the three datasets was identified in 72.4% of records and HBIG administration was recorded for only 2.3% of births.

CONCLUSION

An approach that involves coordinated care and integrates data collection for women with CHB and their infants is required to support the elimination of MTCT of hepatitis B in Victoria.

Evaluation of immunogenicity after first dose of hepatitis B vaccine in newborns with very low birth weight

OBJECTIVE

Hepatitis-B virus (HBV) infection is an important health problem worldwide. HBV vaccine application varies according to the birth weight and gestational week in the neonatal period. This study aimed to reconsider delaying the administration of the HBV vaccine because the birth weight of newborns was very low.

METHODS

The newborns with very low birth weight in the study group were babies weighing less than 2000 g in the postnatal first month and at the time of administering HBV vaccine. Babies born at term from mothers who did not receive an HBV vaccine, had negative hepatitis B surface antibody levels, and were given HBV vaccine at birth were included in the study as a control group. The antibody levels against HBV vaccine were compared between these two groups.

RESULTS

The retrospective study included 60 participants (32 men and 28 women) grouped as control first vaccine weight (first vaccine weight was >2000 g, control group, n = 30) and case vaccine weight (first vaccine weight was <2000 g, case group, n = 30). The mean birth weight was 2976 ± 84.8 g and 1054 ± 44.5 g in the control and case groups, respectively. The first vaccine weight was 2030-3780 g and 960-1900 g in the control and case groups, respectively. The mean antibody level was 297.8 ± 76.3IU/mL and 309.7 ± 56.3IU/mL in the <1500 g and >1500 g groups, respectively. No significant difference was found in hepatitis antibody levels between the groups.

CONCLUSION

Further studies in larger samples are needed to confirm the efficacy and efficiency of postponement of hepatitis B vaccination in babies with a birth weight of <2000 g.

Japanese original delayed hepatitis B vaccination provides adequate immunogenicity against mother-to-child hepatitis B virus infection in preterm infants: A nationwide survey in Japan

OBJECTIVE

We aimed to evaluate immunogenicity following Japanese original delayed hepatitis B (HB) vaccinations for prevention of mother-to-child HB infection in preterm infants.

METHODS

A nationwide survey in Japan was conducted at certified neonatology facilities in 2014. Eighty-four preterm infants born from a serum hepatitis B surface (HBs) antigen-positive mother were included. We collected data on the following parameters: gestational age, birth weight (BW), age at HB vaccination, age at examination of serum anti-HBs titer, and serum anti-HBs titer. The delayed HB vaccination schedule was 3 doses of HB vaccines at 2, 3 and 5 months of age. A seropositive immunogenic response to HB vaccination was defined as an anti-HBs titer ≥10 mIU/mL. Seropositive rates were calculated in all participants. Four subgroups based on BW were as follows: <1000 g (n = 13), 1000-1499 g (n = 16), 1500-1999 g (n = 26), and ≥2000 g (n = 29).

RESULTS

Among 84 preterm infants who completed the delayed vaccination schedule, 82 (98%) achieved seropositive anti-HBs titer at a median age of 6 months. Seropositive rates of infants <1000 g, 1000-1499 g, 1500-1999 g, and ≥2000 g were 92%, 94%, 100%, and 100%, respectively.

CONCLUSION

The Japanese original delayed HB vaccinations achieved sufficient seropositive rates in preterm infants and provide immunogenicity against mother-to-child HB infection.

Serologic Responses After Hepatitis B Vaccination in Preterm Infants Born to Hepatitis B Surface Antigen-Positive Mothers: Singapore Experience

BACKGROUND

The Advisory Committee on Immunization Practices (ACIP) recommends a 4-dose vaccination schedule for preterm low birth weight infants (<2 kg) and a 3-dose vaccination schedule for preterm infants (≥2 kg) born to hepatitis B surface antigen (HBsAg)-positive mothers. However, data remain limited for these high-risk infants, and the optimal dosing schedule in Asia is not well established.

AIM

The aim of this study was to evaluate the serologic vaccine responses in preterm infants born to HBsAg-positive mothers using current vaccination guidelines.

METHODS

Preterm babies of gestation less than 37 completed weeks born to HBsAg-positive mothers were prospectively recruited during 6 years (June 2009 to December 2015) and retrospectively recruited via convenience sampling in 2 years (June 2013 to April 2015) in 2 tertiary pediatric centers. The preterm infants were given 4 or 3 vaccine doses as per ACIP 2005 guidelines. Vaccine response was defined as achieving hepatitis B surface antibody values of >10 IU/L [Abbott Architect (Abbott Laboratories, Chicago, IL)] at 9 months of chronologic age.

RESULTS

A total of 24 preterm infants were recruited. Four had a birth weight <2 kg. Of 23 surviving infants, all were negative for HBsAg. One baby (4.5%) did not achieve adequate vaccine response. All 4 infants with birth weight <2 kg achieved seroprotective values.

CONCLUSION

The current ACIP-recommended vaccination schedule results in adequate antibody responses in preterm infants of HBsAg-positive mothers.

Hepatitis B vaccination coverage and risk factors associated with incomplete vaccination of children born to hepatitis B surface antigen-positive mothers, Denmark, 2006 to 2010

In Denmark, universal screening of pregnant women for hepatitis B has been in place since November 2005, with the first two years as a trial period with enhanced surveillance. It is unknown what the change to universal screening without enhanced surveillance has meant for vaccination coverage among children born to hepatitis B surface antigen (HBsAg)-positive mothers and what risk factors exist for incomplete vaccination. This retrospective cohort study included 699 children of mothers positive for HBsAg. Information on vaccination and risk factors was collected from central registers. In total, 93% (651/699) of the children were vaccinated within 48 hours of birth, with considerable variation between birthplaces. Only 64% (306/475) of the children had received all four vaccinations through their general practitioner (GP) at the age of two years, and 10% (47/475) of the children had received no hepatitis B vaccinations at all. Enhanced surveillance was correlated positively with coverage of birth vaccination but not with coverage at the GP. No or few prenatal examinations were a risk factor for incomplete vaccination at the GP. Maternity wards and GPs are encouraged to revise their vaccination procedures and routines for pregnant women, mothers with chronic HBV infection and their children.

Hepatitis B Postexposure Prophylaxis in Preterm and Low-Birth-Weight Infants

Objective Recommendations for immunoprophylaxis in low-birth-weight (LBW) infants born to hepatitis B surface antigen (HBsAg)-positive mothers vary. We successfully immunized an HBsAg-exposed infant (birth weight: 400 g) and performed a literature review on the outcome of postexposure immunoprophylaxis in HBsAg-exposed preterm and LBW infants. Methods By use of PubMed we identified articles relevant to the topic. Studies were included if the intended vaccine schedule was completed and follow-up data were reported. Results Antibody response was reported in 31 LBW infants (birth weight < 2,500 g) and 49 infants with gestational age of < 38 weeks. Low anti-HBs antibody levels (< 100 IU/L) were found in 9 (29%) of the 31 LBW infants. Overall, 2 of 20 (10%) preterm infants and 2 of 17 (12%) LBW were HBsAg-positive on follow-up. In one study, none of the 26 exposed very LBW infants became infected. Conclusion Due to heterogeneity in immunization schedules, lack of information on transmission rates, and the small number of included subjects, no firm conclusions can be drawn regarding the optimal postexposure prophylaxis in LBW infants. We propose that active and passive immunization at birth should be completed by three further active doses (0-1-2-12 month schedule) until further prospective studies are available.

Infection with hepatitis B and C virus in Europe: a systematic review of prevalence and cost-effectiveness of screening

BACKGROUND

Treatment for chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection is improving but not benefiting individuals unaware to be infected. To inform screening policies we assessed (1) the hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus antibody (anti-HCV-Ab) prevalence for 34 European countries; and (2) the cost-effectiveness of screening for chronic HBV and HCV infection.

METHODS

We searched peer-reviewed literature for data on HBsAg and anti-HCV-Ab prevalence and cost-effectiveness of screening of the general population and five subgroups, and used data for people who inject drugs (PWID) and blood donors from two European organizations. Of 1759 and 468 papers found in the prevalence and cost-effectiveness searches respectively, we included 124 and 29 papers after assessing their quality. We used decision rules to calculate weighted prevalence estimates by country.

RESULTS

The HBsAg and anti-HCV-Ab prevalence in the general population ranged from 0.1%-5.6% and 0.4%-5.2% respectively, by country. For PWID, men who have sex with men and migrants, the prevalence of HBsAg and anti-HCV-Ab was higher than the prevalence in the general population in all but 3 countries. There is evidence that HCV screening of PWID and HBsAg screening of pregnant women and migrants is cost-effective.

CONCLUSION

The prevalence of chronic HBV and HCV infection varies widely between European countries. Anti-HCV-Ab screening of PWID and HBsAg screening of pregnant women and migrants have European public health priority. Cost-effectiveness analyses may need to take effect of antiviral treatment on preventing HBV and HCV transmission into account.

Incidence of acute hepatitis B in different ethnic groups in a low-endemic country, 1992-2009: increased risk in second generation migrants

BACKGROUND

The Netherlands is a low-incidence country for acute hepatitis B (HBV) infection (1.2/100,000 in 2010), where it is typically acquired in adulthood through injecting drug use or homosexual exposure. Recently, the number of heterosexually acquired acute infections in the Netherlands has increased. Ethnicity may be a risk factor. We describe trends in the incidence of acute HBV among heterosexual adults in ethnic groups in Amsterdam from 1992 to 2009 and discuss future control of HBV in the Netherlands.

METHODS

We studied all cases of acute HBV acquired in heterosexuals aged ≥15 years in the Amsterdam region (1992-2009, n=238) by ethnic group. Incidence rates were estimated as the average number of cases per 100,000 per year. Using Poisson regression, we calculated univariable and multivariable incidence rate ratios (IRR) by ethnic group over calendar year, by age and gender.

RESULTS

The incidence in first generation migrants from HBV-endemic countries (FGM) was 4.1/100,000 showing no trend over time. Since 1999, incidence in Dutch-born cases in Amsterdam has increased by 13% annually from 0.2/100,000 in 1999 to 2.1/100,000 in 2009 (annual IRR 1.13, 95% CI:1.0-1.22). From 2004 to 2009, the incidence in native Dutch/Western in Amsterdam was 1.6/100,000 (reference for IRR), in FGM was 4.3/100,000 (IRR of 2.7, 95% CI:1.8-4.2) and in Dutch-born second generation migrants (SGM) was 3.7/100,000 (IRR:2.4, 95% CI:1.2-4.7).

CONCLUSION

Incidence of acute hepatitis B in Amsterdam in FGM and SGM is higher than in the native Dutch population. Low-endemic countries with migrant populations from HBV-endemic areas should consider offering screening and vaccination to both FGM and SGM.

Cultural tailoring for the promotion of hepatitis B screening in Turkish Dutch: a protocol for a randomized controlled trial

BACKGROUND

Chronic hepatitis B virus infection (HBV) is an important health problem in the Turkish community in the Netherlands, and promotion of screening for HBV in this risk group is necessary. An individually tailored intervention and a culturally tailored intervention have been developed to promote screening in first generation 16-40 year old Turkish immigrants. This paper describes the design of the randomized controlled trial, which will be used to evaluate the effectiveness of the two tailored internet interventions as compared to generic online information on HBV, and to assess the added value of tailoring on socio-cultural factors.

METHODS/DESIGN

A cluster randomized controlled trial design, in which we invite all Rotterdam registered inhabitants born in Turkey, aged 16-40 (n = 10,000), to visit the intervention website is used. A cluster includes all persons living at one house address. The clusters are randomly assigned to either group A, B or C. On the website, persons eligible for testing will be selected through a series of exclusion questions and will then continue in the randomly assigned intervention group. Group A will receive generic information on HBV. Group B will receive individually tailored information related to social-cognitive determinants of screening. Group C will receive culturally tailored information which, next to social-cognitive factors, addresses cultural factors related to screening. Subsequently, participants may obtain a laboratory form, with which they can be tested free of charge at local health centres. The main outcome of the study is the percentage of eligible persons tested for HBV through to participation in one of the three groups. Measurements of the outcome behaviour and its determinants will be at baseline and five weeks post-intervention.

DISCUSSION

This trial will provide information on the effectiveness of a culturally tailored internet intervention promoting HBV-screening in first generation Turkish immigrants in the Netherlands, aged 16-40. The results will contribute to the evidence base for culturally tailored (internet) interventions in ethnic minority populations. An effective intervention will lead to a reduction of the morbidity and mortality due to HBV in this population. This may not only benefit patients, but also help reduce health inequalities in western countries.

TRIAL REGISTRATION

The Netherlands National Trial Register NTR 2394.

Awareness, knowledge and self-reported test rates regarding Hepatitis B in Turkish-Dutch: a survey

Background

Hepatitis B virus infection is an important health problem in the Turkish community in the Netherlands. To prevent transmission and progression of the disease in this community, increased screening is necessary. This study aimed to determine 1) the levels of awareness and knowledge regarding hepatitis B, comparing these in tested and non-tested Turkish-Dutch in Rotterdam; 2) the self-reported hepatitis B test status in this population, and how this is related to demographic characteristics, knowledge and awareness.

Methods

We conducted a postal survey amongst first and second generation migrants, aged 16 - 40 years.

Results

The response rate was 30.2% (n = 355 respondents). Levels of awareness and knowledge regarding hepatitis B were low, as the majority of respondents (73%) never thought about the disease and 58% of the respondents scored 5 or less out of ten knowledge items. Weighted analysis of self-reports showed a test rate of 15%, and a vaccination rate of 3%. Regression analysis showed that having been tested for hepatitis B was related to being married and higher levels of awareness and knowledge.

Conclusions

This study shows low levels of hepatitis B awareness and knowledge in the Turkish community in Rotterdam. Self-reported test rates are lower in people who are not currently married, and in those who have low levels of awareness and knowledge. Especially, knowledge about the consequences of hepatitis B, such as liver cancer, was lacking. Therefore, a health promotion intervention should foremost raise awareness, and increase knowledge on the seriousness of this disease.

Evaluation of the compliance with recommended procedures in newborns exposed to HBsAg-positive mothers: a multicenter collaborative study

BACKGROUND

Maternal-infant transmission of hepatitis B virus (HBV) during birth carries a high risk for chronic HBV infection in infants with frequent subsequent development of chronic disease. This can be efficiently prevented by early immunization of exposed newborns. The purpose of this study was to determine the compliance with official recommendations for prevention of perinatal HBV transmission in hepatitis B surface antigen (HBsAg) exposed infants.

METHODS

Records of pregnant women at 4 sites in Switzerland, admitted for delivery in 2005 and 2006, were screened for maternal HBsAg testing. In HBsAg-exposed infants, recommended procedures (postnatal active and passive immunization, completion of immunization series, and serological success control) were checked.

RESULTS

Of 27,131 women tested for HBsAg, 194 (0.73%) were positive with 196 exposed neonates. Of these neonates, 143 (73%) were enrolled and 141 (99%) received simultaneous active and passive HBV immunization within 24 hours of birth. After discharge, the HBV immunization series was completed in 83%. Only 38% of children were tested for anti-HBs afterwards and protective antibody values (>100 U/L) were documented in 27% of the study cohort. No chronically infected child was identified. Analysis of hospital discharge letters revealed significant quality problems.

CONCLUSIONS

Intensified efforts are needed to improve the currently suboptimal medical care in HBsAg-exposed infants. We propose standardized discharge letters, as well as reminders to primary care physicians with precise instructions on the need to complete the immunization series in HBsAg-exposed infants and to evaluate success by determination of anti-HBs antibodies after the last dose.

Hepatitis B screening in the Turkish-Dutch population in Rotterdam, the Netherlands; qualitative assessment of socio-cultural determinants

Background

Hepatitis B is an important health problem in the Turkish community in the Netherlands. Increased voluntary screening is necessary in this community, to detect individuals eligible for treatment and to prevent further transmission of the disease.

Methods

We investigated socio-cultural determinants associated with hepatitis B screening in male and female, first and second generation Turkish migrants, by means of Focus Group Discussions.

Results

Socio-cultural themes related to hepatitis B screening were identified; these were social norm, social support, sensitivity regarding sexuality, reputation, responsiveness to authority, religious responsibility, cleanliness and religious doctrine regarding health and disease, and the perceived efficacy of Dutch health care services. Motivating factors were the (religious) responsibility for one's health, the perceived obligation when being invited for screening, and social support to get tested for hepatitis B. Perceived barriers were the association of hepatitis B screening with STDs or sexual activity, the perception of low control over one's health, and the perceived low efficacy of the Dutch health care services. Reputation could act as either a motivator or barrier.

Conclusion

This study identified relevant socio-cultural themes related to hepatitis B screening, which may serve to customize interventions aimed at the promotion of voluntary hepatitis B screening in the Turkish-Dutch population in the Netherlands.

Population-based study on the seroprevalence of hepatitis A, B, and C virus infection in Amsterdam, 2004

In order to enhance screening and preventive strategies, this study investigated the seroprevalence of hepatitis A, B, and C in the general adult urban population and in subgroups. In 2004, sera from 1,364 adult residents of Amsterdam were tested for viral markers. Sociodemographic characteristics were collected using a standardized questionnaire. For hepatitis A, 57.0% was immune. Of first-generation immigrants from Turkey and Morocco, 100% was immune. Of all Western persons and second-generation non-Western immigrants, approximately half was still susceptible. For hepatitis B, 9.9% had antibodies to hepatitis B core antigen (anti-HBc) and 0.4% had hepatitis B surface antigen. Anti-HBc seroprevalences were highest among first-generation immigrants from Surinam, Morocco, and Turkey, and correlated with age at the time of immigration, and among men with a sexual preference for men. Seroprevalence among second-generation immigrants was comparable to Western persons. The seroprevalence of hepatitis C virus antibodies was 0.6%. In conclusion, a country with overall low endemicity for viral hepatitis can show higher endemicity in urban regions, indicating the need for differentiated regional studies and prevention strategies. More prevention efforts in cities like Amsterdam are warranted, particularly for hepatitis A and B among second-generation immigrants, for hepatitis B among men with a sexual preference for men, and for hepatitis C. Active case finding strategies are needed for both hepatitis B and C.

Cancer mortality rates among first and second generation migrants in the Netherlands: Convergence toward the rates of the native Dutch population

This study investigates the difference in cancer mortality rates between migrant groups and the native Dutch population, and determines the extent of convergence of cancer mortality rates according to migrants' generation, age at migration and duration of residence. Data were obtained from the national cause of death and population registries in the period 1995-2000. We used Poisson regression to compare the cancer mortality rates of migrants originating from Turkey, Morocco, Surinam, Netherlands Antilles and Aruba to the rates for the native Dutch. All-cancer mortality among all migrant groups combined was significantly lower when compared to that of the native Dutch population (RR = 0.55, CI: 0.52-0.58). For a large number of cancers, migrants had more than 50% lower risk of death, while elevated risks were found for stomach and liver cancers. Mortality rates for all cancers combined were higher among second generation migrants, among those with younger age at migration, and those with longer duration of residence. This effect was particularly pronounced in lung cancer and colorectal cancer. For most cancers, mortality among second generation migrants remained lower compared to the native Dutch population. Surinamese migrants showed the most consistent pattern of convergence of cancer mortality. The generally low cancer mortality rates among migrants showed some degree of convergence but did not yet reach the levels of the native Dutch population. This convergence implies that current levels of cancer mortality among migrants will gradually increase in future years if no specific preventive measurements are taken.

Effectiveness of a hepatitis A vaccination program for migrant children in Amsterdam, The Netherlands (1992-2004)

OBJECTIVE

To evaluate the impact and effectiveness of risk-group vaccination against hepatitis A targeted at migrant children living in a country with low endemicity of hepatitis A.

METHODS

Retrospective population based data analysis. Routinely collected data on hepatitis A incidence in migrant children and other risk groups in Amsterdam from 1 January 1992 to 2004 were analyzed and related to exposure, immunity and vaccination coverage in migrant children.

RESULTS

The overall hepatitis A incidence in Amsterdam declined after a pediatric vaccine was introduced in 1997. This decline was seen in migrant children traveling to hepatitis A-endemic countries, contacts with hepatitis A patients, primary school students, injecting drug users, and persons with unknown source of infection, but not in men who have sex with men (MSM) or in travelers to endemic countries other than migrant children.

CONCLUSION

The hepatitis A vaccination campaigns are effective: they reduce both import and secondary HAV cases. The campaigns could be more efficient and cost-effective if the hepatitis B vaccinations currently given to these groups were replaced by a combined hepatitis A and B vaccine. This would increase the hepatitis A vaccination coverage considerably and further reduce the hepatitis A incidence.