Materno-foetal transmission of hepatitis B in Saudi Arabia

Clustering infection of hepatitis B virus genotype B4 among residents in Vietnam, and its genomic characters both intra- and extra-family

Vietnam has a high rate of hepatitis B virus (HBV) infection and a high mortality rate from hepatocellular carcinoma. We performed a detailed genetic analysis of 48 residents and four families from Binh Thuan Province, a southern coastal area of Vietnam. The route of infection and genomic characteristics related to hepatocellular carcinoma (HCC) were studied in HBV spread among carriers that we detected in our previous hepatitis survey. The HBV genotype was B4 in 91.7% and C1 in 8.3% of the cases. The intra-family’s HBV sequence homology was high at 96.8–99.4%. However, it was also high at 99.4–99.8% among residents of the same age and sex as family members. In addition, full genome analysis was performed in 21 cases. The core region of all 20 isolates with genotype B4 was a recombinant of genotype C, and pre-S deletion was found in 20% of cases. The promoter mutation G1613A was found in 13.6% of cases, and a 24 bp insertion from nt1673 in the X region was found in 6.3% of cases. The phylogenetic tree and homology analysis of the HBV full genome suggested the probability and its possibility of horizontal transmission not only within families nor vertical transmission but within cohorts of the same generation in the population. Moreover, the HBV genotype B4 isolates were found not only to be recombinants of genotype C, which results in a high cancer risk, but also to have other risk of HCC, pre-S deletions, the G1613A mutation, and X region insertions corresponding to the promoter. These genomic characters were suggested to be one of the factors to explain the high HCC mortality rate in Vietnam.

The clinical implications of hepatitis B virus genotypes and HBeAg in pediatrics

Although a successful vaccine against HBV has been implemented in 184 countries, eradication of hepatitis B virus (HBV) is still not on the horizon. There are over 240 million chronic carriers of HBV globally. The risk of developing chronic hepatitis ranges from >90% in newborns of hepatitis Be antigen (HBeAg)‐positive mothers, 25%–35% in children under 5 years of age and <5% in adults. HBeAg, a non‐particulate viral protein, is a marker of HBV replication. This is the only HBV antigen to cross the placenta, leading to specific unresponsiveness of helper T cells to the capsid protein and HBeAg in newborns. HBeAg is tolerated in utero and acts as a tolerogen after birth. Perinatal transmission is frequent when mothers are HBeAg‐positive, whereas it occurs less frequently when mothers are HBeAg‐negative. Sequence heterogeneity is a feature of HBV. Based on an intergroup divergence >7.5% across the complete genome, HBV is classified phylogenetically into at least nine genotypes. With between ~4% and 8% intergroup nucleotide divergence, genotypes A–D, F, H and I are classified further into subgenotypes. HBV genotypes/subgenotypes may have distinct geographical distribution and can develop different mutations in the regions of the HBV genome that code for HBeAg. These differences can be related to the role of HBV genotypes to the natural history of infection and mode of transmission. Thus genotypes/subgenotypes of HBV can be responsible for the different natural history of infection and modes of transmission in children, found in various regions of the world, where different genotypes/subgenotypes prevail. Copyright © 2016 John Wiley & Sons, Ltd.

Pregnancy and chronic hepatitis B virus infection

The combination of chronic hepatitis B virus (HBV) infection and pregnancy presents unique management questions. Aspects of care that need to be considered include effects of hepatitis B on pregnancy, effects of pregnancy itself on the course of hepatitis B infection, treatment of hepatitis B during pregnancy and prevention of mother-to-infant transmission. Chronic HBV infection is usually mild in pregnant women, but may flare shortly after delivery. Effect of HBV infection on pregnancy outcomes are generally favorable, but may depend on severity of liver disease. Mother-to-infant transmission can be minimized by current immunoprophylaxis strategies, however, high levels of viremia in mothers may be a factor in the small but reproducible failure rate of current immunoprophylaxis strategies. Use of antivirals during pregnancy needs to be individualized. Careful planning and management of pregnancy must be done among patients with chronic HBV infection.

Comparative efficacy of two dosages of recombinant hepatitis B vaccine in healthy adolescents in India

BACKGROUND

Inclusion of hepatitis B vaccine in the Universal Programme of Immunization of all Asian and African countries is hampered by the economic burden on the health budget because of the cost of hepatitis B vaccines. Here we evaluated the immunogenicity, safety, efficacy, and the persistence of antibody to hepatitis B surface antigen (anti-HBs) titers of a new and a low cost recombinant hepatitis B vaccine GeneVac B, with 2 different dosages in healthy adolescents in India.

METHODS

GeneVac-B, a recombinant hepatitis B vaccine (Serum Institute of India, Pune, India), was administered in 10 or 20 microg dose intramuscularly to 2 groups of 100 healthy school-going adolescents at 0-, 1-, and 6-month intervals, who were followed up for 1 year. Group I received 20 mug doses whereas Group II received 10 mug doses. Blood samples were collected 1 month after each dose and 1 year after the third dose. The anti-HBs titers were assayed using commercially available kits to assess the immunogenicity of the 2 dosage schedules. Safety studies were also carried out.

RESULTS

The geometric mean titer value of the anti-HBs titer 1 month after the third dose was 2629 (mlU/mL) in Group I and 1373 mlU/mL for Group II subjects. One year after the third dose, the persistence of anti-HBs in those who had received 20 mug was 2262 mlU/mL whereas it was 1039 mlU/mL in the group receiving 10 microg doses. All the subjects in both the groups were seroprotected at 1 year after vaccination. None of the vaccinees exhibited serious adverse reactions throughout the study period.

CONCLUSIONS

The study demonstrated the immunogenicity of the recombinant hepatitis B vaccine, and confirms that the 0.5 mL (10 microg) dose of GeneVac B can be administered with satisfactory safety and immunogenicity to adolescents up to 19 years of age, reducing the cost to less than U.S. $1.00 per dose making it acceptable for the Universal Programme of Immunization of developing and under developed countries.

Comparison of three different recombinant hepatitis B vaccines: GeneVac-B, Engerix B and Shanvac B in high risk infants born to HBsAg positive mothers in India

AIM: To evaluate a low cost Indian recombinant hepatitis B vaccine GeneVac-B^® for its immunogenicity and safety in comparison to Engerix B^® and Shanvac B^® vaccine in high risk newborn infants born to hepatitis B surface antigen (HBsAg) positive mothers.

METHODS: A total of 158 infants were enrolled in the study. Fifty eight infants were enrolled in the GeneVac-B^® group while 50 each were included for Engerix B^® and Shanvac B^® groups. A three-dose regimen of vaccination; at birth (within 24 h of birth), 1st mo and 6 mo. were adopted with 10 μg dosage administered uniformly in all the three groups. Clinical and immunological parameters were assessed for safety and immunogenicity of the vaccines, in all the enrolled infants.

RESULTS: Successful follow up until seven months of age was achieved in 83% (48/58) for GeneVac-B^®, 76% (38/50) and 64% (32/50) for Engerix B^® and Shanvac B^® groups respectively. 100% seroconversion and seroprotection was achieved in all the three groups of infants. The geometric mean titers of anti-HBs one month after the completion of three dose of vaccination were 90.5, 80.9 and 72.5 mIU/mL in GeneVac-B^®, Engerix B^® and Shanvac B^® vaccine group respectively. Furthermore the level of anti-HBs increases with age of babies who were born to HBsAg positive mothers. The GMT values of anti-HBs were 226.7, 193.9 and 173.6 mIU/mL respectively in GeneVac-B^®, Engerix B^® and Shanvac B^® groups one year after the completion of the three doses of vaccine. No systemic reactions were reported in infants during the entire vaccination process of GeneVac-B^® and the other two vaccines. Clinical safety parameters remained within the normal limits throughout the study period.

CONCLUSION: The study concludes that there is no significant difference between the three recombinant hepatitis B vaccines. Administration of these vaccines within 24 h of birth to babies, born to HBsAg positive mothers will reduce the incidence of HBV infection.

Screening of pregnant Saudi women for hepatitis B surface antigen

BACKGROUND

The high prevalence of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in pregnant women is considered the most important factor contributing to the higher carrier rate of HBsAg in some populations, including Saudi Arabia. Universal hepatitis B vaccination in infancy was implemented in Saudi Arabia in 1990 to avoid early acquisition of infection. At the same time, another program was launched to vaccinate all school children at school entry as a second target group. The aim of this study was to evaluate the HBsAg prevalence rate in Saudi pregnant women 12 years after launching the program and to assess regional variation, if any.

METHODS

In a cross-sectional study, 2664 pregnant Saudi women were recruited from the five main regions in Saudi Arabia. Blood samples were tested for HBsAg. Positive samples were tested also for HBeAg.

RESULTS

Of 2664 pregnant Saudi women, 65 were positive for HBsAg (2.46%, 95% CI=2.11%-2.69%). Four were positive for HBeAg (0.15%). The HBsAg prevalence rate was higher in Gizan (4.2%) and lower in Tabuk (1.4%) (P=-0.035). Only one case was positive for HBsAg in women under the age of 20 years (1/186), a 0.5% positivity rate in this age group compared with 2.6% in the older age group (P=-0.049 for the one-sided test). A history of surgical procedures was associated with a higher (3%), but not significantly higher rate of HBsAg positivity. No significant association was found between HBsAg positivity and a history of dental procedures or blood transfusion.

CONCLUSION

Although the HBsAg prevalence rate among Saudi pregnant women was lower than previously published data, the full impact of the hepatitis B vaccination program in infancy and childhood will take more years to decrease the prevalence rate in pregnant women. The MOH should continue to give the first dose of hepatitis B vaccine at birth to prevent early acquisition, but in the meantime a regional policy can be adopted to deal with the high prevalence rate of HBsAg among pregnant Saudi women.

The epidemiology and prophylaxis of hepatitis B in sub-Saharan Africa: a view from tropical and subtropical Africa

There are approximately 50 million chronic carriers of hepatitis B virus (HBV) in Africa, with a 25% mortality risk. In sub-Saharan Africa, carrier rates range from 9-20%. Many studies have suggested that HBV transmission in Africa occurs predominantly in childhood, by the horizontal rather than the perinatal route. The exact mode of transmission is uncertain but probably involves percutaneous infection through saliva or traces of blood, as well through unsterile needles, tribal scarification, and other possible vehicles. Compared with adult HBsAg carriers in the Far East, those in Africa have a low rate of HBeAg positivity, which may account for the relatively low rates of perinatal infection. It is also possible that African infants are less susceptible to perinatal HBV infection compared with their Asian counterparts. Alternatively, it may be that African infants are indeed infected with HBV at birth but, for genetically determined reasons, have persistently negative tests for a number of years until the virus is reactivated. In view of the high HBV carrier rates in the general population, universal immunisation of all infants is recommended. Ways of incorporating the hepatitis B vaccine into the Expanded Programme on Immunisation in each country are being evaluated.

Familial clustering of hepatitis B virus infections and prevention of perinatal transmission by immunization with a reduced number of doses in an area of intermediate endemicity (Tunisia)

Hepatitis B surface antigen (HBsAg) was detected in 3.3% of 7162 pregnant Tunisian women tested and HBeAg in 9.6% of the HBsAg-positive mothers. Family members of 46 of these HBsAg-positive mothers (33 husbands and 61 children aged 1-6 years) were investigated for the presence of HBV markers. HBsAg was detected in 21% of the children and 18% of the husbands. Fifty children born to HBsAg-positive mothers received hepatitis B vaccine at birth, at the age of 2-3 months and at the age of 9 months. After immunization, anti-HBs were detected in 92% of them with an anti-HBs geometric mean titre of 415 mIU ml-1. Compared with the HBsAg carrier state in older siblings, the protective efficacy was estimated to be 60%. It was 100% for infants born to HBeAg-negative mothers, but only 31% for those born to HBeAg-positive mothers. For a better efficacy, the schedule of the EPI needs to be modified to include an immunization session at 1 month of age.

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.

Experience with interferon in chronic hepatitis B in Egypt

Forty patients with compensated chronic active hepatitis B and elevated aminotransferases who were HBsAg and HBeAg positive were randomised to a treatment group receiving recombinant interferon alpha-2b (rIFN alpha-2b) or no treatment as a control group. The treated patients were divided into 2 groups, group I (n = 12) received IFN in a dose of 5 MU/m2 thrice weekly by subcutaneous injection for 16 weeks, and group II (n = 8) received the same dose daily for the same duration. Patients were followed up for 12 months after therapy ended. Initiation of IFN therapy was associated with an increase in aminotransferases, reaching a peak at 4-6 weeks in most patients, associated with clearance of HBeAg. At end of follow-up, 81% of the treated patients had cleared HBeAg vs 33% of the control group (p less than 0.01). Changes in other HBV markers were more frequent in the treated patients, though insignificantly. The type of response to therapy was significantly related to the duration of illness, being shortest in those who cleared HBsAg. A complete response to therapy with loss of HBsAg was associated with marked reduction in biochemical and histological activity. A partial response with clearance of HBeAg was associated with moderate improvement in biochemical parameters and ongoing activity in liver histology; whereas persistence of HBeAg was associated with elevated aminotransferases and histological deterioration in most cases. The rise in aminotransferases during seroconversion was associated with hepatic decompensation and death on 3 occasions: one during spontaneous seroconversion, and the other 2 during IFN therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

WHO strategy for the global elimination of new cases of hepatitis B

Hepatitis B infection and its sequelae remain major public health problems internationally despite the existence of sensitive tests to screen blood and blood products for hepatitis B surface antigen (HBsAg) and immunogenic vaccines. Since the human hepatitis B virus has no known animal reservoir, a systematic vaccination programme against hepatitis B, including vaccination of all newborns and young children within the framework of the WHO Expanded Programme on Immunization, as well as protection of high-risk individuals, together with the testing of all blood and blood products for HBsAg, could eliminate hepatitis B virus infection and its sequelae. However, for the successful realization of this programme, many important and difficult problems need to be solved, especially those related to vaccination strategy, determination of the duration of immunity, investigation of the mechanisms of perinatal and horizontal virus transmission, and improvement of the immunogenicity of hepatitis B vaccine. The problem of the hepatitis B carrier is also paramount as the eradication of hepatitis B can be achieved only after the 300 million carriers of the disease in the world today are either cured or dead.

Combined immunoprophylaxis in the prevention of perinatal transmission of hepatitis B and hepatitis D virus infections in Saudi children

The efficacy of the combined immunoprophylaxis approach (passive plus active immunization) was evaluated in babies born to 52 HBsAg-carrier Saudi mothers, of whom seven (13.5%) were HBeAg-positive and seven were anti-HDV-positive. Newborns were given 100 IU of hepatitis B immune globulin (HBIG) from the Hepuman Berna-Swiss Serum and Vaccine Institute, Berne, and hepatitis B vaccine (5 micrograms) within 12 hours of birth, and the vaccine was given again at 1 and 6 months of age (5 micrograms/injection). After 18 months of follow-up, all but one baby had protective levels of antibody to HBsAg and none of the babies born to anti-HDV-positive carrier mothers showed evidence of HDV infection. These results show that the combined immunoprophylaxis approach is quite successful in protecting against perinatal transmission of HBV and HDV in the Saudi population. Furthermore, early vaccination against HBV will also protect against HDV infection later in life.

Baseline seroepidemiology of hepatitis B virus infection in two Saudi high-risk groups: patients on haemodialysis and patients with congenital bleeding disorders

Because background seroepidemiological data are required before nationwide vaccination against hepatitis B virus (HBV) is attempted, the rate of exposure to HBV was investigated in two high-risk Saudi groups: patients on haemodialysis and patients with congenital bleeding disorders. Although the HBsAg carrier rate was higher in patients with congenital bleeding disorders (11.1%) than in patients on haemodialysis (4.6%), the exposure rate to HBV was similar in both groups (38.8%-44.5%). Because of this high exposure rate it seems cost-effective, at least in the Saudi population or in countries which are endemic for HBV, to screen for HBV markers before vaccination against HBV is recommended.

Lack of evidence for transplacental transmission of HBV infection by HBsAg-carrier mothers

The possibility of transplacental transmission of HBV infection was investigated in 54 HBsAg-carrier Saudi mothers and their newborns. Controls were 60 Saudi mothers with previous exposure to HBV, and their newborns. Thirteen cord blood samples were HBsAg-positive by ELISA, including three from mothers with previous exposure to HBV, compared with one sample which was HBsAg- and HBeAg-positive and three samples which were only HBeAg-positive. Eight of the 13 cord blood samples which were HBsAg-positive by ELISA were haemolysed sera and were found to be HBsAg-negative by RIA and RPHA. None of the infants' sera, taken within 1-4 days of delivery, was positive for HBsAg or IgM anti-HBc. These results indicate that HBV markers in cord blood are either false-positive or due to contamination by maternal blood rather than an indication of in utero infection.

Hepatitis B surface antigen associated nephrotic syndrome

Hepatitis B virus (HBV) has been reported in association with the nephrotic syndrome from different parts of the world, but its role as a cause of the pathological findings of nephrotic syndrome is still controversial. We report seven nephrotic children with positive hepatitis B markers in which members of their families were also positive for the markers but without clinical, renal or hepatic involvement. Four showed haematuria at onset and three developed hypertension later in the course of the disease. Only two were responsive to steroid therapy. Renal biopsy was performed in four, of whom three showed membranous nephropathy and the other showed mesangioproliferative glomerulonephritis. Four patients developed end-stage renal disease. We conclude that in our environment HBV, when detected in children with nephrotic syndrome, should not be considered as a chance finding, but may have a definite role in its pathogenesis. Moreover, the prognosis of HBV-associated nephrotic syndrome appears poor.

Maternal-infant transmission of hepatitis B in Egypt

In order to determine whether maternal-infant (vertical) transmission of hepatitis B is a common route of infection leading to chronic antigenemia in Egypt, 901 asymptomatic women in labor were evaluated. Forty-three women (4.8 percent) were positive for HBsAg, but only one woman was positive for HBeAg. From one year of observation of children born to 13 of the HBsAg-positive mothers, vertical transmission of hepatitis B was estimated to have occurred in approximately 1.7% of births, with chronic antigenemia resulting from 0.6% of births. It was also possible to observe 29 children born to women negative for HBsAg. Horizontal transmission of hepatitis B occurred in 17.2 percent of these children during the first year of life. Maternal-infant transmission of hepatitis B at birth does not appear to be the predominant mechanism of hepatitis B transmission or a common cause of chronic antigenemia in Egypt. The first year after birth appears to be a more important period of hepatitis B transmission. Therefore, vaccination of all children at birth with hepatitis B vaccine could be an effective vaccine strategy despite a low incidence of vertical hepatitis B transmission.

Perinatal transmission of hepatitis B virus in high-incidence countries

Hepatitis B is a serious public health problem throughout the world. Hepatitis B virus (HBV) induces acute hepatitis with a case-fatality rate of about 1%. Even more important, 5-10% of patients infected with HBV become chronic carries and about 25% of these will die due to cirrhosis and hepatocellular carcinoma. The reservoir of HBV chronic carriers in the world is estimated at more than 200 million people and 80% of them reside in Asia and the western Pacific. In high-incidence areas, such as south-east Asia, perinatal transmission of HBV from carrier mothers to newborns appears to be the most important factor for the high prevalence of HBV infection and 70-90% of infants born to HBsAg/HBeAg-positive mothers become chronic carriers. Three possibilities of transmission of HBV from carrier mothers to newborns are suggested: (a) transplacental transmission in utero - it was estimated that such transmission occurred in 5-15% of newborns; (b) transmission during delivery, which is considered the main mode of perinatal transmission; (c) postnatal transmission from mother to newborn, which is not common. HBeAg is the main maternal factor in determining whether infection of newborns will occur; the expression of this antigen seems to be determined genetically. Recently it has shown that immunoprophylaxis is highly effective in preventing the development of the carrier state in infants born to HBsAg/HBeAg-positive mothers. Only 5-10% of high-risk infants are not protected by vaccination. If it becomes possible to immunize the entire world population including all babies born to carrier mothers at birth, and if our knowledge of the mechanisms of perinatal transmission of HBV is accurate, the carriers and acute cases of HB ought to disappear in two to three generations.

Hepatitis B virus perinatal transmission among Arab women

One thousand five hundred and fifty-four Arab women were screened at delivery for the presence of hepatitis B virus (HBV) antigenaemia in their sera. Forty-five or 2.9% were found to be positive. Only three of 41 (7.3%) of these hepatitis B surface antigen-positive (HbsAg) mothers were found to be positive for the presence of hepatitis B e antigen (HBeAg), 27 (65.8%) had anti-HBe and the remaining 11 (26.8%) had neither HBeAg nor its corresponding antibody. These results, therefore, predicted a low rate of transmission of virus from mother to newborn. Follow-up for 4-13 months after delivery on 14 of these HBsAG-positive mothers and their infants indicated that in only one infant born to an HBeAg-positive mother did HBV antigenaemia develop. Another infant died from undetermined causes. Therefore, HBV perinatal transmission among Arabs, unlike that among populations in Southeast Asia, does not appear to contribute in an important way to the pool of carriers in this population.

The prevalence of hepatitis B serological markers in dental personnel

There is a need to assess the risk to members of the dental profession in the U.K. of acquiring hepatitis B from patients. Towards this end a study was performed in order to determine the degree of carriage of serological markers of hepatitis B in a sample of dental workers in and around Edinburgh. Of a total of 88 persons tested only one, a dental assistant, was positive. She had evidence of past infection but did not give a history of previous jaundice. We conclude that in the Edinburgh area the risk of dental personnel acquiring hepatitis B from patients is very small and that routine active immunisation is not necessary. Those who volunteer to treat known hepatitis B virus (HBV) carriers should be offered immunisation and the recommendations of the expert group of the Health Departments of Great Britain on the treatment of HBV carriers should be implemented.