Evaluation of a hepatitis B vaccination program in Chiang Mai, Thailand

Chiang Mai is a province in northern Thailand that started a vaccination program for hepatitis B virus (HBV) infection in 1989. In this paper, we report the long-term efficacy of this program. Of children aged 4-9 years, 65.7% had a complete course and 3.8% had an incomplete vaccination course. Urban schoolchildren had higher percentage of HB vaccination than rural schoolchildren (89.1% vs 46.9% for the complete course, p < 0.001). The overall prevalence rate of HBsAg in Chiang Mai schoolchildren was 1.2%, with no significant differences between gender (p = 0.496) and school areas (p = 0.477). Anti-HBc antibodies were detected in 6.9% of children. Overall, 26.2% of children had protective levels of anti-HBs antibodies (> 10.0 mlU/ml), and 11.2% had low levels of these antibodies (1.0-9.9 mlU/ml). Compared to previous reports, our results show a lower percentage of anti-HBs antibodies, 33.8% of children age 4 years had protective anti-HBs antibodies, dropping to 18.4% by age 9 years. Among those anti-HBs seropositive, 9.1% were anti-HBc positive, indicating a natural infection with HBV. We found a small number of children, despite adequate immunization, developed HBV infection.     

Cost-benefit analysis of hepatitis a vaccination in Thailand

We constructed a decision model to simulate costs and benefits for persons in the context of hepatitis A prevention. Three strategies were compared: i) no intervention; ii) vaccination against hepatitis A without screening; iii) vaccination against hepatitis A for those susceptible after screening for anti-HAV. We divided the population into 3 age groups : 3-11 years, 12-18 years and 19-40 years. Data regarding the cost of treatment and vaccination were obtained from the King Chulalongkorn Memorial Hospital. Relevant probabilities were obtained from published literature and expert opinion. At the present incidence of hepatitis A infection, in all age groups examined, the net benefits of a universal no-intervention strategy were higher than those of either vaccination (intervention) strategy. The cost of vaccination without screening in the 3-11-year and 12-18-year groups would equal the benefit if the incidence rates amounted to approximately 138 and 212 infected individuals per 100,000, respectively, that of vaccination with screening at incidence rates of about 200 and 260 infected persons per 100,000, respectively. In the 19-40-year group, the cost incurred by vaccination either with or without screening would equal the benefit at an incidence rate above 450 infected individual per 100,000. For the benefits to outweigh the estimated vaccination costs at present the vaccine is still too expensive. The cost of vaccination without screening in the 3-11-year group would equal the benefit if the cost of vaccine was about 586 baht/2 doses (293 baht/dose), and about 500 baht/2 doses (250 baht/dose) in the 12-18-year group. Likewise, because of the cost of vaccine, it would not be cost-beneficial in the 19-40-year group both with and without screening, and neither would it be in the 3-11-year and 12-18-year groups including screening. According to current standards, under the conditions of the present study the benefit of hepatitis A vaccination administered to the general population between the age of 3 and 40 years in Thailand does not justify the expenses incurred. Major changes in hepatitis A incidence, anti-HAV seroprevalence, vaccine cost or the treatment outcome would be required to potentially render either intervention strategy cost beneficial.     

Baseline sero-epidemiology of hepatitis B virus infection in children and teenagers in Italy. A survey before mass hepatitis B vaccination

During the period May 1987 to November 1989, the prevalence of hepatitis B virus (HBV) markers was determined by ELISA in serum samples of 7405 (55% male, 45% female) apparently healthy persons 3-19 years of age in Italy. Earlier studies of adults there had shown an intermediate degree of HBV endemicity (hepatitis B surface antigen carrier rate greater than 2%). Persons were selected by systematic cluster sampling in five different geographical areas of Italy. The overall prevalence of hepatitis B surface antigen (HBsAg) was 0.6%. The overall prevalence of at least one marker of HBV was 2.8%; it increased from 1.7% among children 3-5 years of age to 4.5% in teenagers 17-19 years of age (P less than 0.001). The prevalence of any HBV marker was higher in southern then in northern areas (3.5% vs. 1.8%, P less than 0.001). A significant association was found with sociodemographic features. Persons whose fathers had less than 6 years of schooling had a 2.3-fold risk (C.I. 95% = 1.5-3.4) while those belonging to a household of six or more under one roof had a 1.7-fold risk (C.I. 95% = 1.2-2.4) of previous exposure to HBV infection. These findings indicate that, today in Italy, exposure to HBV infection at a young age is very low and suggest a shift towards a low degree of endemicity following improvements in socio-economic conditions, decreased family size and increasing use of disposable syringes during recent years.(ABSTRACT TRUNCATED AT 250 WORDS)     

Seroepidemiology of hepatitis B virus infection in Saudi Arabian children: a baseline survey for mass vaccination against hepatitis B.

Saudi Arabia is considered to be an area of endemic hepatitis B virus (HBV) infection. By adult age, 7% persons have hepatitis B surface antigen (HBsAg) and about 70% have one or more HBV markers. In order to provide a baseline for the integration of hepatitis B vaccine into the extended programme of immunisation (EPI), a population-based survey of HBV markers was made among Saudi children. The overall prevalence of HBsAg was 6.7%, with at least one HBV marker being positive in 19.7% persons tested. Two peaks of HBV prevalence were observed in the 7- and 10-year-old children respectively. The prevalence of HBsAg was steady in all age groups with identifiable but insignificant peaks in children aged 4 and 7 years respectively. Despite the apparent homogeneity of the Saudi population, the prevalence rates of HBV varied among the regions and were higher in urban dwellers. There was no significant difference in the HBsAg prevalence for the sexes (7.3% for males and 6.0% for females). Socioeconomic factors and family size did not significantly influence the prevalence of HBV among children. Of 307 HBsAg-positive children, 55 (17.9%) were positive for HBeAg. The early acquisition of HBV in the Saudi population is confirmed. The most effective strategy for HBV control, therefore, is by mass vaccination of all Saudi infants. An extension of the immunisation programme so as to include all pre-school children should further reduce the reservoir of HBV in Saudi Arabia. A repetition of a similar survey after 5 and 10 years should be made in order to measure this reduction.     

Effectiveness of hepatitis B virus vaccination program in Egypt:Multicenter national project

AIM:To assess the effectiveness of hepatitis B virus(HBV) vaccination program among fully vaccinated children.METHODS:A national community based crosssectional study was carried out in 6 governorates representing Egypt. A total of 3600 children aged from 9 mo to 16 years who were fully vaccinated with HBV vaccine during infancy were recruited. Face to face interviews were carried out and sera were evaluated for hepatitis B surface antigen(HBsA g),anti-HBV core antibodies(total) and quantitative detection of hepatitis B surface antibody using enzyme linked immunoassays techniques. Samples positive to HBs Ag/anti-HBV core antibodies were subjected to quantitative HBV-DNA detection by real time polymerase chain reaction with 3.8 IU/L detection limit. RESULTS:Sero-protection was detected among 2059 children(57.2%) with geometric mean titers 75.4 ± 3.6 IU/L compared to 3.1 ± 2.1 IU/L among nonseroprotected children. Multivariate logistic analysis revealed that older age and female gender were the significant predicting variables for having non seroprotective level,with adjusted odds ratio 3.3,9.1and 14.2 among children aged 5 to 10,10 to 15 and ≥ 15 years respectively compared to those 5 years and 1.1 among girls compared to boys with P 0.01. HBs Ag was positive in 0.11% and breakthrough infection was 0.36% and 0.39% depending on positivity of anti-HBc and DNA detection respectively. The prevalence of HBV infection was significantly higher among children aged ≥ 7 years(0.59%) compared to 0.07% among younger children with odds ratio equal to 8.4(95%CI:1.1-64.2) and P 0.01.The prevalence was higher among girls(0.48%) than boys(0.29%) with P 0.05. C ON C LU S I ON :T he E gy pt ian c ompuls or y H B V vaccination program provides adequate protection. Occult HBV infection exists among apparently healthy vaccinated children. Adherence to infection control measures is mandatory.     

Efficacy of accelerated hepatitis B vaccination program in patients being actively treated for hematologic malignancies.

BACKGROUND: The goal of this study was to conduct an accelerated vaccination program and to determine its efficacy in patients susceptible to hepatitis B virus (HBV) receiving chemotherapy because of their hematologic malignancies. METHODS: Over a one-year period, a total of 327 patients who were diagnosed as having a hematologic malignancy were serologically analyzed in terms of HBV infection. Of those found to be susceptible to HBV infection, a total of 42 patients consisting of 16 females and 26 males were enrolled in the accelerated vaccination program. All the patients were administered a 20-microg yeast-derived recombinant hepatitis B vaccine on days 0, 14, and 28. Anti-HBs titers above 10IU/l at 1 and 3 months after the final dose were accepted as protective. RESULTS: A total of 146 (44.6%) patients were susceptible to HBV, while 13 (4.0%) were carriers, 28 (8.6%) were vaccinated, and 113 (34.5%) had had a previous HBV infection. A total of 42 patients (16 females and 26 males, mean age 34.5+/-10.9 years) were enrolled in the vaccination program. Overall, 23.8% (10/42) of the patients in the program had developed anti-HBs at one month after the last vaccination. CONCLUSIONS: Poor results obtained by different vaccination programs suggest the need for alternative strategies to prevent the disease.     

Seroepidemiology of antibody to hepatitis A in the rural eastern part of Thailand.

Hepatitis A is a disease commonly found in Thai children. However, there are very few reports on the age specific prevalence in Thailand. We studied the hapatitis A virus (HAV) antibody titer in a population in the rural eastern part of Thailand, using an antiHAV ELISA test (Abbott Laboratories, North Chicago Ill). Three hundred and sixty four subjects from Pong Nam Ron, Chanthaburi Province and 236 of children and adults from Bo Thong, Chon Buri Province were studied for age specific prevalence of antiHAV. The immunity against HAV increased with age. Fifty percent of Pong Nam Ron children had antiHAV antibodies at the age of 8-9 years and at the age of 12-13 years of Bo Thong children. The overall antibody prevalence rate was 67.9% in Pong Nam Ron and 59.3% in Bo Thong Districts. According to our data, less than 30 percent of children under 10 years old in the eastern part of Thailand were seropositive for HAV. This finding indicated a much lower incidence than previously reported which may reflect better personal and food hygiene.     

Long-term immunogenicity of hepatitis B vaccination in children and adolescents in a southern Italian town

Purpose

Universal anti-hepatitis B vaccination of infants and of 12-year-old children became mandatory in Italy in 1991. The purpose of this study was to evaluate the persistence of anti-hepatitis B surface (HBs) antibodies several years after a primary course of vaccination.

Methods

In 2010, anti-HBs titers were measured in all subjects aged between 5 and 25?years residing in a southern Italian town. Individuals with an anti-hepatitis B antibody concentration of 10?IU/ml or more were considered to be protected.

Results

Of the 671 subjects evaluated, 149 (30%) lacked protective antibodies. Fifty-three (29.4%) of the subjects had been vaccinated ??10?years earlier and 96 (30.3%) more than 10?years earlier (P?=?not significant). Subjects vaccinated in infancy were more likely to lack protective anti-HBs antibodies than subjects vaccinated at 12?years of age, regardless of the years elapsed since immunization.

Conclusions

Most subjects maintained protective antibodies for a considerable number of years after vaccination. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy.     

Rheumatic disorders developed after hepatitis B vaccination.

OBJECTIVE: To obtain an overview of rheumatic disorders occurring after hepatitis B vaccination. METHODS: A questionnaire was sent to rheumatology departments in nine French hospitals. Criteria for entry were rheumatic complaints of 1 week's duration or more, occurrence during the 2 months following hepatitis B vaccination, no previously diagnosed rheumatic disease and no other explanation for the complaints. RESULTS: Twenty-two patients were included. The observed disorders were as follows: rheumatoid arthritis for six patients; exacerbation of a previously non-diagnosed systemic lupus erythematosus for two; post-vaccinal arthritis for five; polyarthralgia-myalgia for four; suspected or biopsy-proved vasculitis for three; miscellaneous for two. CONCLUSIONS: Hepatitis B vaccine might be followed by various rheumatic conditions and might trigger the onset of underlying inflammatory or autoimmune rheumatic diseases. However, a causal relationship between hepatitis B vaccination and the observed rheumatic manifestations cannot be easily established. Further epidemiological studies are needed to establish whether hepatitis B vaccination is associated or not with an incidence of rheumatic disorders higher than normal.     

Therapeutic vaccination in chronic hepatitis B

AIMS: The aim was to test the efficacy of a pre-S2-containing vaccine (Genhevac-B) in chronic hepatitis B (CHB). Twenty-five naive patients (22 male, three female; median age 35; range: 6-69 years) with CHB were recruited. The inclusion criteria were: hepatitis B e antigen (HBeAg) positive or HBV-DNA detectable with liquid hybridization; alanine aminotransferase (ALT) is at least 1.5-fold the upper normal limit and histological evidence of chronic hepatitis. METHODS: In the first period, all patients received monthly injections of 20, 40 and 60 microg of the vaccine. One month after the last injection, patients who still had HBV-DNA were divided into two randomly assigned groups. While the patients in the first group and the patients who lost HBV-DNA in the first period continued to receive monthly injections of 20 microg vaccine for a further 6 months, the patients in the second group received 9 MU interferon alpha-2b (Roferon-A), three times per week using the same method as for the first group. Patients were followed up after 12 months without treatment. Response was defined as the loss of HBV-DNA and normalization of ALT. RESULTS: Six of the 25 patients lost HBV-DNA after 3 months. Nine of the remainder were randomly placed in the first group (vaccine-only) and 10 were placed in the second group (vaccine + interferon). End-of-treatment response was achieved, overall, 8/15 from the vaccine group and 6/10 from the combination. One patient from each group relapsed during the follow up. Overall, the sustained response (SR) rate was 46% (7/15) in the vaccine group, and 50% (5/10) in the combination group. Histological improvement was achieved in 6/7 SR with vaccine-only and all five with combination treatment, while 1/8 of failures of vaccine and 2/5 of failures of combination improved. CONCLUSIONS: It was concluded that Genhevac-B decreases serum HBV-DNA levels in the majority of patients with CHB and sustained clearance was achieved in some patients. Combination of interferon-alpha with Genhevac-B is effective for the vaccine failures and may increase sustained response compared to interferon-alpha alone. However, the mechanism of action is yet to be explained.     

Results of hepatitis B vaccination in sarcoidosis

BACKGROUND: Sarcoidosis is known to be associated with defects in cellular immunity, especially in reference to T helper lymphocytes. Anergy to a tuberculin skin test is most characteristic of this disease. OBJECTIVES: To further the data on impaired immunity, we studied the antibody response to hepatitis B vaccination in patients with sarcoidosis. METHODS: Serologic markers of hepatitis B virus (HBV) (HBsAg, anti-HBs, anti-HBc) were studied in 40 patients with sarcoidosis (32 female, 8 male; mean age: 45 +/- 11 years, range: 25-66 years) with a mean duration of disease of 6 years. While all the markers were negative in 22 patients (55%), 2 had isolated anti-HBc positivity and 16 had both anti-HBc and anti-HBs antibodies. Thirty-five age- and sex-matched healthy subjects were studied as controls. Recombinant HBV vaccines (Genhevac B Pasteur, 20 microg) were administered (at 0, 1, and 6 months) to 16 of the seronegative cases and the controls and antibody titres were measured 1 month after the last dose. The tuberculin skin test was negative in all cases. RESULTS: While none of the vaccinees in the diseased group responded, the control group yielded an antibody response rate of 85. 7% (30/35), with a mean titre of 257.9 mIU/ml. CONCLUSIONS: Patients with sarcoidosis were invariably unresponsive to standard vaccination, while some of the diseased subjects had already mounted a natural antibody response, either before or after the development of the original disease. Cellular immunodeficiency in sarcoidosis could be a suitable model for studying immunological interactions between HBV and the host.