A reduction in chronic hepatitis B virus infection prevalence among children in Vietnam demonstrates the importance of vaccination

Background

Vietnam has high endemic hepatitis B virus infection with >8% of adults estimated to have chronic infection. Hepatitis B vaccine was first introduced in the national childhood immunization program in 1997 in high-risk areas, expanded nationwide in 2002, and included birth dose vaccination in 2003. This survey aimed to assess the impact of Vietnam's vaccination programme by estimating the prevalence of hepatitis B surface antigen (HBsAg) among children born during 2000–2008.

Methods

This nationally representative cross-sectional survey sampled children based on a stratified three-stage cluster design. Demographic and vaccination data were collected along with a whole blood specimen that was collected and interpreted in the field with a point-of-care HBsAg test.

Results

A total of 6,949 children were included in the survey analyses. The overall HBsAg prevalence among surveyed children was 2.70% (95% confidence interval (CI): 2.20–3.30). However, HBsAg prevalence was significantly higher among children born in 2000–2003 (3.64%) compared to children born 2007–2008 (1.64%) (prevalence ratio (PR: 2.22, CI 1.55–3.18)). Among all children included in the survey, unadjusted HBsAg prevalence among children with ≥3 doses of hepatitis B vaccine including a birth dose (1.75%) was significantly lower than among children with ≥3 doses of hepatitis B vaccine but lacked a birth dose (2.98%) (PR: 1.71, CI: 1.00–2.91) and significantly lower than among unvaccinated children (3.47%) (PR: 1.99, CI: 1.15–3.45). Infants receiving hepatitis B vaccine >7 days after birth had significantly higher HBsAg prevalence (3.20%) than those vaccinated 0-1 day after birth (1.52%) (PR: 2.09, CI: 1.27–3.46).

Conclusion

Childhood chronic HBV infection prevalence has been markedly reduced in Vietnam due to vaccination. Further strengthening of timely birth dose vaccination will be important for reducing chronic HBV infection prevalence of under 5 children to <1%, a national and Western Pacific regional hepatitis B control goal.     

Prevalence of chronic hepatitis B virus infection before and after implementation of a hepatitis B vaccination program among children in Nepal

Background

In Nepal, an estimated 2–4% of the population has chronic hepatitis B virus (HBV) infection. To combat this problem, from 2002 to 2004, a national three dose hepatitis B vaccination program was implemented to decrease infection rates among children. The program does not currently include a birth dose to prevent perinatal HBV transmission. In 2012, to assess the impact of the program, we conducted a serosurvey among children born before and after vaccine introduction.

Methods

In 2012, a cross-sectional nationally representative stratified cluster survey was conducted to estimate hepatitis B surface antigen (HBsAg) prevalence among children born from 2006 to 2007 (post-vaccine cohort) and among children born from 2000 to 2002 (pre-vaccine cohort). Demographic data, as well as written and oral vaccination history were collected. All children were tested for HBsAg; mothers of HBsAg positive children were also tested. Furthermore, we evaluated the field sensitivity and specificity of the SD Bioline HBsAg rapid diagnostic test by comparing results with an enzyme immunoassay.

Results

Among 2181 post-vaccination cohort children with vaccination data by either card or recall, 86% (95% confidence interval [CI] 77–95%) received ≥3 hepatitis B vaccine doses. Of 1200 children born in the pre-vaccination cohort, 0.28% (95% CI 0.09–0.85%) were positive for HBsAg; of 2187 children born in the post-vaccination cohort, 0.13% (95% CI 0.04–0.39%) were positive for HBsAg (p = 0.39). Of the six children who tested positive for HBsAg, two had mothers who were positive for HBsAg. Finally, we found the SD Bioline HBsAg rapid diagnostic test to have a sensitivity of 100% and a specificity of 100%.

Conclusions

This is the first nationally representative hepatitis B serosurvey conducted in Nepal. Overall, a low burden of chronic HBV infection was found in children born in both the pre and post-vaccination cohorts. Current vaccination strategies should be continued.     

Efficacy of yeast-derived recombinant hepatitis B vaccine after being used for 12 years in highly endemic areas in China

Objective

To evaluate the long-term efficacy and duration of yeast-derived recombinant hepatitis B vaccine in hepatitis B virus (HBV)-endemic areas.

Method

A cross-sectional investigation was carried out in five HBV-endemic areas. Children who were born between 1997 and 2008 and vaccinated with yeast-derived recombinant hepatitis B vaccine were selected. Serum samples were taken to test HBV infection markers by microparticle enzyme immunoassay, and the results were compared to those before vaccination.

Results

7066 subjects were enrolled. The average adjusted hepatitis B surface antigen (HBsAg) prevalence was 1.02%. HBV core antibody (anti-HBc) prevalence was 3.54%. The overall percentage of HBsAg(−)&Anti-HBc(−)&Anti-HBs(+) was 61.34%. With time after immunization, the percentage annually decreases from 86.11% in 2008 to 49.80% in 1997. Geometric mean concentration (GMC) of anti-HBs decreased significantly annually. The portion of GMC = 100–999.9 mIU/ml was 48.0% in 2008, and decreased to 16.7% in 1997.

Conclusion

HBsAg prevalence decreased dramatically. This shows that the yeast-derived recombinant hepatitis B vaccine is effective and stable after being used for 12 years in HBV-endemic areas. It is not suggested to carry out booster immunization.     

Epidemiological serosurvey of Hepatitis B in China—Declining HBV prevalence due to Hepatitis B vaccination

Objective

To determine the prevalence of hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core anti-body (anti-HBc) in a representative population in China 14 years after introduction of hepatitis B vaccination of infants.

Methods

National serosurvey, with participants selected by multi-stage random sampling. Demographics and hepatitis B vaccination history collected by questionnaire and review of vaccination records, and serum tested for HBsAg, antibody to anti-HBc and anti-HBs by ELISA.

Findings

The weighted prevalences of HBsAg, anti-HBs and anti-HBc for Chinese population aged 1–59 years were 7.2%, 50.1%, 34.1%, respectively. HBsAg prevalence was greatly diminished among those age <15 years compared to that found in the 1992 national serosurvey, and among children age <5 years was only 1.0% (90% reduction). Reduced HBsAg prevalence was strongly associated with vaccination among all age groups. HBsAg risk in adults was associated with male sex, Western region, and certain ethnic groups and occupations while risk in children included birth at home or smaller hospitals, older age, and certain ethnic groups (Zhuang and other).

Conclusions

China has already reached the national goal of reducing HBsAg prevalence to less than 1% among children under 5 years and has prevented an estimated 16–20 million HBV carriers through hepatitis B vaccination of infants. Immunization program should be further strengthened to reach those remaining at highest risk.     

Factors associated with effectiveness of the first dose of hepatitis B vaccine in China: 1992–2005

Background

In China, the prevalence of chronic hepatitis B infection was high because of perinatal and early childhood transmission. A three-dose hepatitis B vaccine schedule with a first dose as soon as possible after birth was introduced in 1992 and generalized in 2002 in the Expanded Programme of Immunization (EPI). In 2006, a serological survey evaluated the effectiveness of vaccination.

Methods

We conducted a restricted analysis of the national serological survey that sampled children and collected information on demographic characteristics, birth history, hepatitis B vaccination and hepatitis B surface antigen (HBsAg) status as determined by ELISA testing. We compared children who received the first dose in a timely way (i.e., within 24 h of birth) with others in terms of HBsAg status, stratified by birth cohort and place of birth.

Results

Three-dose hepatitis B vaccine coverage increased from 60.8% for children born in 1992–1997 to 93.2% for children born in 2002–2005. Meanwhile, timely birth dose coverage increased from 38.7% to 74.4%. Among 29,410 children born in 1992–2005 who had received three vaccine doses and no hepatitis B immune globulin, factors associated with being HBsAg-negative in multivariate analysis included receiving a timely birth dose (p = 0.04), birth after 1998 (p < 0.001), living in an urban setting (p = 0.008) and hospital birth (p = 0.001). The relative prevalence of HBsAg among children receiving the timely birth dose was lower for children born in county or larger hospitals (0.39), intermediate in township hospitals (0.73) and highest at home (0.87).

Conclusions

Hospital birth and receiving a timely birth dose are the main determinants of the field effectiveness of the first dose of hepatitis B vaccine. Efforts to increase the proportion of hospital deliveries are key to increasing timely birth dose coverage and its effectiveness.     

Long-term efficacy of 10-12 years after being immunized with Chinese hamster ovary cell derived hepatitis B vaccine in Chinese Rural Communities

Objective

To evaluate the long-term efficacy of Chinese hamster ovary (CHO) cell derived hepatitis B vaccine in country community in China.

Methods

A cross-sectional investigation was carried out. Children who were born between 1997 and 1999 and vaccinated with the three doses of CHO-derived hepatitis B vaccine were selected as study objects. Their serum samples were taken to test for hepatitis B virus (HBV) markers, and the results were compared to that before vaccination. In addition, for HBsAg positive children, their mothers were visited.

Results

1254 Children were enrolled in the study. The prevalence of HBsAg was 0.24% and the vaccine efficacy was 97.0%, similar to that of yeast derived hepatitis vaccines. Among 3 mothers of HBsAg positive children, 2 were HBsAg positive, indicating maternal HBV transmissions.

Conclusion

The long-term efficacy of the CHO-derived hepatitis B vaccine is good and after vaccination maternal transmission is the most important route of spreading HBV.     

Which newborns missed the hepatitis B birth dose vaccination among U.S. children?

Objectives

Hepatitis B birth dose vaccination is a critical step in preventing perinatal hepatitis B virus infection. This study assesses the prevalence of children who missed the birth dose of hepatitis B vaccination and identifies socio-demographic factors associated with non-receipt of the birth dose among children in the United States.

Methods

A survey observation study was conducted with the national representative sample of 17,053 U.S. children aged 19–35 months obtained from the 2009 National Immunization Survey. Categorical data analysis and multivariable logistic regression in the context of complex sample survey were applied to evaluate the prevalence and determine the independent risk factors.

Results

39.2% of children missed the birth dose of hepatitis B vaccination. Children who reside in states without a universal hepatitis B vaccine supply policy, are not covered by health insurance, and have only 1 vaccination provider are significantly associated with non-receipt of the birth dose hepatitis B vaccination.

Conclusions

Children who reside in states without a universal hepatitis B vaccine supply policy, and who are not covered by health insurance are two important modifiable risk factors for not receiving the birth dose hepatitis B vaccination. Future intervention studies could be needed to help control those modifiable risk factors.     

Antibody persistence of two pentavalent DTwP–HB–Hib vaccines to the age of 15–18 months,and response to the booster dose of quadrivalent DTwP–Hib vaccine

Objectives

Antibody persistence in children following three doses of primary vaccination with diphtheria, tetanus, whole-cell-pertussis (DTwP), hepatitis B, and Haemophilus influenzae type b (Hib) vaccines (SIIL Pentavac vaccine vs. Easyfive^® of Panacea Biotec), and response to the booster dose of DTwP–Hib (Quadrovax^®) vaccine.

Methods

Children who completed their primary immunization were assessed for antibodies at 15–18 months of age, and then given a booster dose of DTwP–Hib vaccine. Reactogenicity and safety of the booster dose was evaluated.

Results

Both pentavalent vaccines demonstrated a good immune response at 15–18 months. Following the booster dose, all vaccinated subjects achieved protective titers against diphtheria, tetanus and Hib, whereas the response to pertussis antigen was ∼78%. Fever and irritability was noted in 24%, local pain in 51%, and swelling in 36% of the children following booster dose.

Conclusions

Primary immunization with either pentavalent vaccine induced an excellent immunity lasting till the second year of life. A booster dose with DTwP–Hib (Quadrovax^®) vaccine effectuated a good anamnestic response to all vaccine components, being specially strong for Hib in children previously vaccinated with SIIL liquid pentavalent vaccine (Pentavac^®). Also, the safety profile of SIIL quadrivalent vaccine (Quadrovax^®) administered as booster dose was acceptable.     

Characterization and immune effect of the hepatitis B–BCG combined vaccine for using a needle innoculation

Objective

To prepare the hepatitis B–Mycobacterium bovis Bacillus Calmette-Guérin combined vaccine (HB–BCG combined vaccine) and resolve a needle problem of the two kinds of hepatitis B vaccine (HB vaccine) and M. bovis Bacillus Calmette-Guérin (BCG) for the innoculation.

Methods

The hepatitis B surface antigen (HBsAg) was prepared by the genetic engineering technique, BCG was produced using routine biological technique, and then the finished products of the HB–BCG combined vaccine were processed on the above foundation. The content of HBsAg was measured by Enzyme linked immunosorbent assay (ELISA), the immune effect of BCG was detected by purified protein derivative (PPD) test. Cellular immune response, safety, partial poison and allergy were tested. The stability of HB–BCG combined vaccine was detected by ELISA and viable count method.

Results

The two kinds of antigens (HBsAg and BCG) had good compatibility. The comparison on immune effects of HB–BCG combined vaccine and BCG showed no significant difference. The comparison on immune effects of HB–BCG combined vaccine group (first dose for HB–BCG Combined vaccine, second and third dose for HB vaccine) and HB vaccine group (three dose all for HB vaccine) demonstrated that anti-HBs levels of the HB–BCG combined vaccine group were higher than that of HB vaccine group. No statistical significance was observed between the combined vaccine group and HB vaccine group after three doses immunization schedules. The results of safety in HB–BCG combined vaccine group accorded with that of BCG group, it had been not found the pathological changes of the tuberculosis. The characteristic and process in pathological changes of HB–BCG combined vaccine group and BCG group were similar in the partial poison test. HBsAg did not strengthen the inflammation reaction caused by BCG. Systemic allergy had not been found. The HB–BCG combined vaccine was stable in 2 years.

Conclusion

The immune effects of the HB–BCG combined vaccine were not lower than the two kinds of single dose vaccine, it had good safety.     

Seroprotection after recombinant hepatitis B vaccination among newborn infants: A review

Introduction

Hepatitis B vaccination starting at birth provides a safety net for infants exposed to hepatitis B virus (HBV) during delivery or in early life. Hepatitis B vaccine is recommended in the United States for infants prior to birthing facility discharge, and within the first 12 h of life for infants born to hepatitis B surface antigen (HBsAg)-positive mothers. We performed a literature review and summarized the response to recombinant hepatitis B vaccine among infants.

Methods

Studies published between 1987 and 2011 assessing seroprotection from recombinant hepatitis B vaccine starting within the first 30 days of life were eligible. Seroprotection was defined using an antibody to hepatitis B surface antigen (anti-HBs) threshold of 10 mIU/mL at series completion. Infant seroprotection was compared in trial arms varying by maternal hepatitis B antigen status (e antigen [HBeAg], HBsAg), hepatitis B immune globulin (HBIG) administration, birth weight, vaccine dosage, schedule, and age at first dose.

Results

Forty-three studies were included. The median seroprotection proportion overall was 98% (range 52%, 100%). The final median seroprotection proportions did not vary appreciably by maternal HBsAg status, HBIG administration, or schedule. Higher compared to lower dosage resulted in earlier increases in anti-HBs but not in final seroprotection proportions. Infants with birth weights <2000 g compared to ≥2000 g had lower median seroprotection proportions (93% and 98%, respectively). Median seroprotection proportions were also lower when infants with birth weights <2000 g were vaccinated at 0–3 days of age compared to 1 month of age or older (68% versus 95%, respectively).

Conclusion

High levels of protection from recombinant hepatitis B vaccine are achieved in term infants vaccinated at birth, effectively preventing transmission of HBV and resultant morbidity and mortality. Implications, if any, for long-term protection are unknown for differences in responses among infants vaccinated at birth compared to ages older than 1 month.     

Prevention of perinatal hepatitis B virus transmission in the Netherlands, 2003-2007: children of Chinese mothers are at increased risk of breakthrough infection

Background

In the Netherlands, different hepatitis B vaccination schedules have been used for children born to HBV-infected mothers. All schedules included a birth dose of hepatitis B immunoglobuline (HBIg). We assessed determinants of perinatal HBV transmission and determinants of anti-HBs titers in infants born to HBsAg positive mothers.

Methods

We included infants born to HBV infected mothers between 1.1.2003 and 30.6.2007, using national databases and a separate database for Amsterdam. Risk factors for perinatal transmission and determinants of the anti-HBs titer were studied using logistic and linear regression, respectively.

Results

Of 2657 infants registered in the national database, 91% were registered to have received HBIg and at least three hepatitis B vaccinations. In Amsterdam, this coverage among 413 children at risk was higher (96%, p < 0.01). Serological test results for 2121 infants (80%) indicated that 13 (0.6%) were HBsAg positive. A mother of Chinese descent was the only risk factor for perinatal HBV infection identified (RR 9.1, 95% CI 3.1–26.8). Receiving a birth dose of hepatitis B vaccine later than in the first week of life was not associated with an increased risk of perinatal HBV infection. A shorter period between last vaccination and testing, and having received more doses of hepatitis B vaccine were independently associated with a higher anti-HBs titer.

Conclusions

Infants born to Chinese mothers were at increased risk of perinatal HBV infection. All HBsAg positive pregnant women of Chinese origin should be assessed to determine whether there is an indication for anti-viral treatment during pregnancy. Among infants who received HBIg at birth, we did not detect an increased risk of perinatal HBV infection when the first dose of hepatitis B vaccine was administered after the first week of life.     

Hepatitis B seroprevalence in HIV-infected patients consulting in a public day care unit in Bobo Dioulasso,Burkina Faso

Objective

The authors had for aim to assess the prevalence of hepatitis B co-infection in a cohort of HIV-infected patients, routinely followed-up at the Day Care Unit of the Bobo Dioulasso Sanou Souro University Hospital, Burkina Faso.

Patients and methods

The Elisa technique was used to dose HBs antigen (AgHBs), antibodies anti-HBs and anti-HBc in all the patients followed by the biological laboratory, from October to December 2008.

Results

The AgHBs prevalence was 12.7% [CI at 95%: 10.7–15.0%] and men were slightly more likely to be positive for AgHBs than women (16.5% [12.0–21.9%] versus 11.6% [9.4–14.1%]; P = 0.047); 83.3% of the patients [80.8–85.6%] were positive for hepatitis B core antibody, and 32.6% [29.7–35.6%] for hepatitis B surface antibody; 29.9% of the patients [27.1–32.8%] had a complete profile of former hepatitis B infection, 41.3% [38.2–44.4%] expressed core antibodies only; 13.8% [11.7–16.0%] had a negative serological test, and 2.3% [1.5–3.4%] presented a vaccinal immunity.

Conclusion

These results stress the usefulness of screening for hepatitis B in all HIV-infected patients, along with the initial biological tests. This would help adapt HIV treatment to co-infected patients and to build an expanded program of vaccination for non-immune patients.     

Stable seroepidemiology of hepatitis B after universal immunization in Taiwan: A 3-year study of national surveillance of primary school students

Background

This study is aimed to investigate if there was increased risk of HBV acquisition among first graders in Taiwan during a 3-year follow-up period.

Methods

A total of 1545 healthy first graders, who were vaccinated against HBV in infancy, were recruited in 2005. All subjects were checked for hepatitis B surface antigens (HBsAg), antibodies to HBsAg (anti-HBs), and to the hepatitis B core antigen (anti-HBc). Nucleotide sequence of the “a” determinant of HBsAg was determined by polymerase chain reaction and direct sequencing in the HBsAg carriers.

Results

Among 1545 subjects, 0.78% were HBsAg seropositive, 54.30% were anti-HBs seropositive, and 1.68% anti-HBc seropositive. Three of the 10 HBV carriers (30%), whose HBV DNA were sequenced for the S gene, had surface antigen mutants at the “a” determinant.

Conclusion

There were no new chronic HBV infections in this cohort of children for two consecutive years. HBV S gene vaccine escape mutants did exist in the vaccine-failure population, but they may not have made a major health impact.     

Effects of hepatitis B immunization on prevention of mother-to-infant transmission of hepatitis B virus and on the immune response of infants towards hepatitis B vaccine

Background

Combined immunization with hepatitis B immunoglobulin (HBIG) plus hepatitis B vaccine (HB vaccine) can effectively prevent perinatal transmission of hepatitis B virus (HBV). With the universal administration of HB vaccine, anti-HBs conferred by HB vaccine can be found increasingly in pregnant women, and maternal anti-HBs can be passed through the placenta. This study was designed to evaluate the effect of hepatitis B immunization on preventing mother-to-infant transmission of HBV and on the immune response of infants towards HB vaccine.

Method

From 2008 to 2013, a prospective study was conducted in 15 centers in China. HBsAg-positive pregnant women and their infants aged 8–12 months who completed immunoprophylaxis were enrolled in the study and tested for HBV markers (HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc). Antepartum administration of HBIG to HBsAg-positive women was based on individual preference. HBsAg-negative pregnant women and their infants of 7–24 months old who received HB vaccines series were enrolled and tests of their HBV markers were performed.

Results

1202 HBsAg-positive mothers and their infants aged 8–12 months were studied and 40 infants were found to be HBsAg positive with the immunoprophylaxis failure rate of 3.3%. Infants with immunoprophylaxis failure were all born to HBeAg-positive mothers of HBV-DNA ≥ 6 log₁₀ copies/ml. Among infants of HBeAg-positive mothers, immunoprophylaxis failure rate in vaccine plus HBIG group, 7.9% (29/367), was significantly lower than the vaccine-only group, 16.9% (11/65), p = 0.021; there was no significant difference in the immunoprophylaxis failure rate whether or not antepartum HBIG was given to the pregnant woman, 10.3% (10/97) vs 9.0% (30/335), p = 0.685. Anti-HBs positive rate was 56.3% (3883/6899) among HBsAg-negative pregnant women and anti-HBs positive rate was 94.2% in cord blood of anti-HBs-positive mothers. After completing the HB vaccine series, anti-HBs positive rate among infants with maternal anti-HBs titers of <10 IU/L, 10–500 IU/L and ≥500 IU/L was 90.3% (168/186), 90.5% (219/242) and 80.2% (89/111) respectively, p = 0.011. Median titers of anti-HBs (IU/L) among infants in the three groups was 344.2, 231.9 and 161.1 respectively, p = 0.020.

Conclusions

HBIG plus HB vaccine can effectively prevent mother-to-infant transmission of HBV, but no HBV breakthrough infection was observed in infants born to HBeAg-negative mothers who received HB vaccine with or without HBIG after birth. Antepartum injection of HBIG has no effect on preventing HBV mother-to-infant transmission. High maternal titer of anti-HBs can transplacentally impair immune response of infants towards HB vaccine.     

Seasonal influenza vaccine effectiveness in pre- and full-term children aged 6–23 months over multiple seasons

Introduction

This study aimed to determine the effectiveness of seasonal influenza vaccine in pre- and full-term children aged 6–23 months.

Methods

We examined a cohort of 683,354 young children (7.7% preterm) over five influenza seasons (2004–2005 to 2008–2009) in Ontario, Canada. Vaccine effectiveness was estimated using influenza-coded ambulatory visits during virologically-confirmed influenza season periods as the outcome and multivariable Cox proportional hazards modeling.

Results

Full vaccination was associated with a 19% reduction in influenza-coded ambulatory visits (HR = 0.81; 95% CI, 0.68–0.97) in all children, and an 18% reduction in full-term children (HR = 0.82; 95% CI, 0.68–0.99). We did not find significant vaccine effectiveness for preterm children. No benefit was found for partial vaccination.

Conclusions

In children younger than two years, only full influenza vaccination is associated with reduced influenza-coded ambulatory visits. Since the effectiveness of influenza vaccination in preterm children remains uncertain, further study of this highly vulnerable population is warranted.     

Long-term efficacy of plasma-derived and recombinant hepatitis B vaccines in a rural township of Central Taiwan

Aims

To assess the differences of long-term efficacy between plasma-derived and recombinant hepatitis B virus (HBV) vaccines and the effectiveness of catch-up vaccination in adolescents with undetectable anti-HBs.

Methods

Before 1992, infants born in Taiwan were immunized using plasma-derived HB vaccine, and thereafter, by using recombinant HB vaccine. From the only junior middle school of a rural township in central–southern Taiwan, 1788 (93.7%) students from five cross-sectional screenings, grouping into three birth cohorts (Group I: born during 1984–1986, II: 1986–1992 and III: 1992–1995), were enrolled for checking HBsAg, anti-HBs and anti-HBc. Students with undetectable HBsAg and anti-HBs underwent a booster dose (2.5 ug) of recombinant HB vaccine (Engerix-B; GlaxoSmithKline, Rixensart, Belgium) and had anti-HBs re-checked 3 weeks later. Individuals who had remained undetectable for anti-HBs completed the other two doses of HB vaccines at 1 and 6 months later.

Results

The prevalence of HBsAg (11.4, 5.4 and 1.2%), anti-HBs (64.5, 44.1 and 36.0%) and anti-HBc (29.5, 12.5 and 4.4%) decreased from Group I to III (P < 0.001 for trends). After a booster dose, the positive rates of anti-HBs increased up to 80.5% (16% increase) in Group I, 81.0% (36.9% increase) in Group II, and 94.4% (58.4% increase) in Group III. The percentages of anamnestic response increased with a trend (P < 0.001). A total of 110 non-responders completed 3 doses of catch-up HB vaccination, but 3 cases (2.7%) of Group II, evoked primary vaccination response.

Conclusion

Recombinant vaccine showed predominant disappearance rate (62.7%) of anti-HBs 12–15 years after vaccination, but provided better anamnestic response after a booster dose. It also showed high success rate (97.3%) in catch-up vaccination in adolescents.     

Safety and immunogenicity of a recombinant hepatitis B vaccine manufactured by a modified process in renal pre-dialysis and dialysis patients

Background

Patients with renal insufficiency are hyporesponsive to vaccination, including to hepatitis B vaccines. A manufacturing process modification for a hepatitis B vaccine (mpHBV) was studied in renal pre-dialysis and dialysis patients.

Methods

This randomized, open-label, multicenter, estimation study enrolled previously unvaccinated, HBV-seronegative adult dialysis and pre-dialysis patients (N = 276, median age 72.0 years). At 0, 1, 6, and 8 months, group 1 received a 1 mL intramuscular dose of mpHBV (containing 40 μg HBsAg) as a single injection, while group 2 received a 1 mL intramuscular dose of a licensed hepatitis B vaccine as two injections (each containing 20 μg HBsAg; 40 μg HBsAg total). Serum antibody to HBsAg (anti-HBs) was measured predose 1, and 1 month postdose 3 and 4. Anti-HBs geometric mean concentration (GMC) and seroprotection rate (SPR, % of subjects with anti-HBs titer ≥10 mIU/mL) were estimated at months 7 and 9.

Results

For group 1, month 7 SPR was 48.5% (49/101, 95% CI: 38.4%, 58.7%); with an additional dose, month 9 SPR increased to 66.7% (66/99, 95% CI: 56.5%, 75.8%). For group 2, month 7 SPR was 57.7% (64/111, 95% CI: 47.9%, 67.0%); with an additional dose, month 9 SPR increased to 69.2% (72/104, 95% CI: 59.4%, 77.9%). group 1 GMCs at months 7 and 9 were 27.5 mIU/mL (95% CI: 15.7, 48.0) and 61.7 mIU/mL (95% CI: 34.2, 111.5), respectively. group 2 GMCs at months 7 and 9 were 48.7 mIU/mL (95% CI: 28.7, 82.7) and 115.8 mIU/mL (95% CI: 65.2, 205.5), respectively. There were 22 serious adverse events; none were considered related to study vaccine.

Conclusions

Both formulations were immunogenic in this population but required more vaccinations to reach seroprotective levels than comparable regimens in healthy individuals, as expected. The relatively reduced SPRs seen in this population support the need for routine screening and re-dosing in this population.     

The impact of the universal infant varicella immunization strategy on Canadian varicella-related hospitalization rates

Introduction

Varicella vaccine was introduced to the infant immunization schedule in each province or territory between 2000 and 2007 as a result of the Canadian Immunization Strategy. The impact of vaccinating children against this disease is potentially far reaching, as immunization may also benefit those segments of the population not immunized. The objective of this paper is to examine the effects of varicella vaccine on related hospitalizations across the entire Canadian population.

Methods

This study is an ecological study using annual hospitalization rates in all ten provinces between 1990 and 2010.

Results

There were decreased varicella-related hospitalization rates for all ages across Canada following the introduction of varicella vaccination programs. The majority of changes in hospitalization rates were greater than 70% across all ages less than 40. Statistically significant declines in hospitalization were found for children aged 1–4 (ranges from 65 to 93%), and children less than 1 (ranges from 48 to 100%). Adults aged 20–39 and 40–59 also experienced statistically significant declines (55–100%, and 39–76% respectively).

Conclusion

Results suggest that decreased circulation of varicella appears to significantly contribute to declines in varicella-related hospitalizations for infants <1, as well as adults aged 20–39.     

Global epidemiology of hepatitis B virus infection: new estimates of age-specific HBsAg seroprevalence and endemicity

Objective

Chronic hepatitis B virus infection is one of the most serious infections and a major risk factor for deaths from cirrhosis and liver cancer. We estimate age-, sex- and region-specific prevalence of chronic HBV infection and calculate the absolute number of persons being chronically infected.

Methods

A systematic review of the literature for studies reporting HBV infection was conducted and worldwide HBsAg seroprevalence data was collected over a 27-year period (1980–2007). Based on observed data, age-specific prevalence and endemicity were estimated on a global level and for all world regions for 1990 and 2005 using an empirical Bayesian hierarchical model.

Findings

From 1990 to 2005, the prevalence of chronic HBV infection decreased in most regions. This was particularly evident in Central sub-Saharan Africa, Tropical and Central Latin America, South East Asia and Central Europe. Despite this decrease in prevalence, the absolute number of HBsAg positive persons increased from 223 million in 1990 to 240 million in 2005. Age-specific prevalence varied by geographical region with highest endemicity levels in sub-Saharan Africa and prevalence below 2% in regions such as Tropical and Central Latin America, North America and Western Europe. Asian regions showed distinct prevalence patterns with lower intermediate prevalence in South Asia, but up to 8.6% HBsAg prevalence in East Asia. Strong declines were seen in South East Asian children.

Conclusion

Declines in HBV infection prevalence may be related to expanded immunization. The increasing overall number of individuals being chronically infected with HBV, and the widespread global differences in HBV prevalence call for targeted approaches to tackle HBV-related mortality and morbidity. HBV infection prevalence data are needed at country and sub-national level to estimate disease burden and guide health and vaccine policy.     

Effectiveness of a Chinese hamster ovary cell derived hepatitis B vaccine in Chinese rural communities

Objective

To evaluate the effectiveness of a Chinese hamster ovary cell derived hepatitis B vaccine in a country community in Hebei Province, PR China.

Method

A cross-sectional investigation was carried out in 4 of 7 randomly selected country communities in Zhengding County in 2005. All of the children who were born between 1997 and 1999 were selected as study objects. Their serum samples were taken to test for HBV markers, and HBsAg prevalence was compared to that of the same age group before hepatitis B vaccination in 1983. In addition, for HBsAg positive children, their mothers were visited and tested for serum HBV markers, in order to distinguish maternal HBV transmissions.

Results

Among the 2205 children of the selected birth cohort, 1696 (76.9%) were visited. The prevalence of HBsAg was 0.53%, and by comparing to that of before hepatitis B vaccination, the effectiveness was 95.3%, similar to that of yeast derived hepatitis B vaccines. Among 7 mothers of HBsAg positive children, 5 were HBsAg positive, indicating maternal HBV transmissions; and although one mother was HBsAg negative, her kid was not vaccinated, which indicates a horizontal transmission. As for the other kid, he was adopted and the HBV infection status of his birth mother was unknown.

Conclusion

The effectiveness of the CHO derived hepatitis B vaccine is comparable to yeast derived ones, and after the hepatitis B vaccination maternal transmission is the most important route of spreading HBV.