Immune response to hepatitis B vaccine in a group of health care workers in Sri Lanka

Hepatitis B Virus vaccination post serological testing and antibody levels of vaccinated health care workers in Accra, Ghana

Introduction

Hepatitis B Virus (HBV) infection is an important occupational hazard to Health Care Workers (HCWs) all over the world. International health organizations have strongly recommended the use of the HBV vaccine, especially among individuals at risk of HBV infection. A laboratory test aimed at measuring Anti-HBs concentration (titer) 1-2 months following a 3-dose vaccination schedule is the most reliable approach for diagnosing seroprotection against HBV. This study sought to assess post-vaccination serological testing, seroprotection against HBV, and associated factors among vaccinated HCWs in Ghana.

Methods

A hospital-based analytical cross-sectional study involving 207 HCWs. Pretested questionnaires were used to collect data. 5mls of venous blood were collected from consenting HCWs under strict aseptic conditions and quantitatively analyzed for Anti-HBs using ELISA procedures. SPSS Version 23 was used to analyze data with the level of significance set at 0.05.

Results

Median age; 33, IQR of 29-39. The post-vaccination serological testing rate was 21.3 %. HCWs with high-risk perception and working at the regional hospital had lower odds of adherence to post-vaccination serological testing (aOR = 0.2; 95 % CI = 0.1-0.7) and (aOR = 0.1; 95 % CI = 0.1-0.6) p < 0.05. The seroprotection rate was 91.3 % (95 % CI = 87 %-95 %). Minority, 18 (8.7 %) of the 207 vaccinated HCWs had antibody titers below 10mIU/mL and were not seroprotected against HBV. Geometric Mean Titers (GMTs) were higher in those who received three doses, took a booster, and were less than 25 kg/m².

Conclusion

The post-vaccination serological testing practice was sub-optimal. The seroprotection rate was higher with higher GMTs in those who adhered to the 3-dose vaccination regimen, took a booster dose, and had BMI < 25 kg/m². It may be inferred that those with Anti-HBs below 10 IU/ml had their antibodies diminishing or waning off with time or they are true vaccine non-responders. This observation calls for strict adherence to post-vaccination serological testing, especially for HCWs who are at high risk of percutaneous and mucocutaneous exposures that could result in HBV infection.

Post vaccination antibody titres of hepatitis B surface antigen (anti-HBs) in a mixed cohort of health care workers

Background

Hepatitis B (HepB) is an important vaccine preventable infection among healthcare workers (HCWs). Vaccination against Hep B virus, remains the foremost preventive approach. This study aims to measure the antibody titres to Hep B surface antigen (anti-HBs) in a mixed cohort of HCWs. It also aims to study the association between time since vaccination and the anti-HBs titres thus evaluating the duration of seroprotection.

Methods

A total of 200 HCWs, including nursing students (n = 112), nursing staff (n = 49), laboratory technicians (n = 30) and doctors (n = 9) who had received all three doses of the Hep B vaccine and met the inclusion criteria of having taken all three doses of vaccine were included in this study. Anti-HBs titres were estimated by bioMérieux mini VIDAS® automated immunoassay based on the principle of enzyme-linked fluorescence assay.

Results

Two hundred subjects aged 19 to 52 years were included in the study; mean age was 27.29 ± 0.568 years. Duration since vaccination in the study cohort was ≤ 5 years in 149 (74.5.0%), 6-10 years in 20 (10.0%) and >10 years in 31 (15.5%) subjects. Postvaccination antibody titres were > 100 mIU/ml in 85.0%, 10-100 mIU/ml in 11.0% and ≤ 10 mIU/ml in 3.5%. There was a decline noted in antibody titres as duration after vaccination increased. Increasing age was associated with falling protective titres.

Conclusion

The study revealed that majority of the HCWs had adequate anti-HBs titres and were protected after vaccination.

Hepatitis B surface antibody levels among health-care personnel vaccinated against hepatitis B in a teaching hospital in South India

Background:

Hepatitis B virus infection is a global health priority, and health-care personnel (HCP) have 10 times higher prevalence than the general population. Seromonitoring identifies those with low titers and vaccine nonresponders with increased risk.

Objective:

The objective of the study was to assess hepatitis B surface antibody (anti-HBs) titers and associated factors among HCP vaccinated against hepatitis B in a teaching hospital in Kerala.

Methods:

A cross-sectional study was done among 454 vaccinated HCP, and anti-HBs antibody titers were assessed by enzyme-linked immunosorbent assay method.

Results:

Participants included 162 (35.7%) doctors, 132 (29.3%) nursing and laboratory personnel, and 160 (35.3%) supporting staff. The mean age was 38.06 ± 11.33 years, and 72% were female. Majority (92.5%, 420) were seroprotected and 78.9% (358) with high (>100 mIU) titers. Moderate (10–100 mIU) and low (<10 mIU) level seroprotection was seen in 13.7% (62) and 7.5% (34), respectively. Incomplete vaccination, >10 years since vaccination, and age >40 years were independent predictors for poor seroprotection, while increasing doses and boosters were positively associated.

Conclusions:

Majority of vaccinated HCP were seroprotected. Incomplete schedules, older age, and prolonged time since vaccination can lead to decline in titers, and periodical seromonitoring should guide hepatitis B revaccination strategies.

Clinical Evaluation of Plasma Separation Cards as a Tool to Collect, Store, and Test Blood Samples for Hepatitis B and C Serological Markers

BACKGROUND

The plasma separation card (PSC) is a new device for collecting finger-pricking-derived small amount of blood in a solid support that is stable at room temperature and can be archived, mailed, and processed at a later time. This tool can facilitate screening at risk populations located in rural areas without local health care infrastructures. We evaluated the performance of PSC in the collection and preparation of blood samples for the determination of hepatitis B and C serological markers.

METHODS

Blood obtained from 334 consecutive patients referred for the detection of hepatitis B surface antigens (HBsAg), hepatitis B surface antibodies (anti-HBs) and hepatitis C antibodies (anti-HCV) was analyzed in parallel using standard (STD) and PSC-based sample collection and preparation procedures. Results obtained from STD or PSC processed samples were compared for their detection rate and correlation.

RESULTS

Using STD, we detected 5 samples positive for HBsAg, 150 for anti-HBs, and 23 for anti-HCV with a rate of concordance with PSC of 100%, 100%, and 91% respectively. The 100% concordance observed for anti-HBs was based on a cutoff of 2.6 IU/L for PSC-derived sample corresponding to the 10 IU/L threshold associated with immunity to hepatitis B. STD and PSC showed a good correlation (R2 = 0.85) in the detection of anti-HBs titers. The 2 anti-HCV PSC negative samples had no detectable viremia.

CONCLUSIONS

These data confirm the utility of PSC as a tool to support viral hepatitis screening programs in rural areas lacking local clinical infrastructures and testing facilities.

Immune response to hepatitis B vaccine following complete immunization of children attending two regional hospitals in the Southwest region of Cameroon: a cross sectional study

BACKGROUND

Hepatitis B virus (HBV) infection despite being a vaccine preventable disease remains a global public health problem. In Cameroon, the hepatitis B vaccine was introduced in the expanded program on immunisation in 2005, but there has been limited evaluation of the HBV surface antibody response post vaccination.

OBJECTIVE

We investigated the immune response to hepatitis B vaccine in infants who received the DPT-Hep B-Hib vaccine, and we assessed HBsAg carriage in non-responders. We also investigated factors associated with non-response or poor response.

METHODS

Using a hospital based cross sectional design and a structured questionnaire over a four-month period (January to April 2019), we collected data to determine factors associated with hepatitis B surface antibody (anti-HBs) response from infants aged 6 to 9 months attending infant welfare clinics (IWC) at the Buea and Limbe regional hospitals. We collected venous blood and measured anti-HBs titres using a quantitative Foresight® ELISA. We entered and analysed data using EpiData version 3.1 and SPSS version 25 respectively.

RESULTS

Of the 161 infants enrolled, 159 (98.8%) developed anti-HBs antibodies. Of these 159, 157 (97.5%) and 117 (72.7%) developed ≥ 10.0 mIU/ml (seroprotection) and ≥ 100.0 mIU/ml anti-HBs titres respectively. Being younger (6 months old) was associated with seroprotection (Cramer V = 0.322, p = 0.001). Spearman rho's relational analysis showed that immunity against HBV reduced as the duration since the last dose increased (r = -0.172; P = 0.029). However, a Firth logistic regression showed no significant association of factors with inadequate immunity. All 12 (7.5%) infants exposed to HBV at birth, received the hepatitis B vaccine at birth, including four who received HBIG, and all were protected. Four infants (2.5%) had anti-HBs titres < 10.0 mIU/mL (non-responders) but had no peculiarity.

CONCLUSION

The seroprotective rate following hepatitis B vaccination of infants is high even in exposed infants. Our study suggests that Cameroon's HBV vaccine in the Expanded Program on Immunisation (EPI) is effective against HBV, although we could not account for the 2.5% non-response rate. Large scale studies are needed to further explore non-response to the vaccine.

Immunogenicity and safety of HBAI20 Hepatitis B vaccine in non-responders: Double-blinded, randomised, controlled phase 2 trial

BACKGROUND & AIMS

Approximately 5%-10% of the general population respond inadequately to licensed recombinant hepatitis B vaccines. We assessed the immunogenicity and safety of a new HBAI20 vaccine, consisting of a new AI20 adjuvant (20-µg recombinant human IL-2 attached to 20-µg aluminium hydroxide) in combination with HBVaxPro®-10 µg.

METHODS

In a double-blinded, randomised, controlled phase 2 trial, 18- to 59-year-old healthy non-responders (titre <10 mIU/ml after three or more doses of hepatitis B vaccine) were assigned (3:1 ratio) to receive either HBAI20 vaccine or HBVaxPro®-10 µg in a 0, 1 and 2-month schedule. The primary outcome was seroprotection (titre ≥ 10 mIU/ml) measured 1-3 months following the third vaccination.

RESULTS

A total of 133 participants were randomised to receive either HBAI20 vaccine (n = 101) or HBVaxPro®-10 µg (n = 32). In the modified intention-to-treat analysis, the seroprotection rate after the third vaccination was 92.0% (80/87) in the HBAI20 group and 79.3% (23/29) in the HBVaxPro®-10-µg group, P = .068. Using a generalised linear mixed model to adjust for stratification factors, a higher odds of seroprotection with HBAI20 vaccine was shown (adjusted odds ratio = 3.48, P = .028). Frequency of mild and moderate local adverse events was greater in the HBAI20 group than in the HBVaxPro®-10 µg. Rates of severe local adverse events and systemic adverse events were low and similar in both groups.

CONCLUSIONS

In this group of hepatitis B vaccine non-responders, the HBAI20 vaccine demonstrated a higher seroprotection rate when adjusting for stratification factors and a similar safety profile compared to the licensed recombinant HBVaxPro®-10 µg.

Adherence and Effectiveness of HBV Vaccination among Healthcare Workers in Egypt

Context:

Healthcare workers (HCWs) face a potential risk of acquiring different bloodborne pathogens, by occupational exposure to contaminated blood and body fluids. Hepatitis B vaccine is a safe, effective method of conferring long-term protection against HBV infection.

Aims:

The study aimed to assess the adherence and effectiveness of HBV vaccination among HCWs at Gastrointestinal Surgical Center, Mansoura University, Egypt.

Settings and Design:

A prospective descriptive study was carried out between June 2019 and December 2019 at Gastrointestinal Surgical Center, Mansoura University, Egypt.

Methods and Material:

All HCWs with anti-HBs levels below 10 mIU/mL were advised to receive 3 doses of recombinant HBV vaccine, at 0, 1, and 6 months. The anti-HBs levels were checked 3 months after the third dose of the HBV vaccine.

Statistical Analysis Used:

Data was analyzed using the Statistical Package of Social Science (SPSS) program for windows (version 16).

Results:

A total of 442 healthcare providers were included. Most of them completed the 3 doses of the vaccine (81.7%), 10.2% refused the vaccine, while 0.9% and 7.2% received 1 and 2 doses, respectively. Odds of vaccination were the highest (88.1%, 273/310) among nurses (OR, 4.7; 95% CI, 2.6–5.2; P ≤ 0.001). The overall anti-HBs positivity of 97% (350/361) was observed. The main reasons for not being vaccinated included the fear of vaccine side effects 25/81 (30.9%) and lack of trust in the vaccine effectiveness 18/81 (22.2%).

Conclusions:

The outcome of the present study emphasizes the need to apply alternative and innovative measures to build a positive attitude toward the HBV vaccine among HCWs.

Efficacy of hepatitis B vaccination in children with rheumatic diseases

BACKGROUND

Vaccination to prevent hepatitis B (HB) virus infection is important for children undergoing immunosuppressive treatment. Information on the efficacy of HB vaccination in children with rheumatic diseases undergoing immunosuppressive therapy is scarce.

METHODS

Children with rheumatic diseases administered HB vaccine during immunosuppressive treatment between May 2013 and September 2016 were enrolled. Patients were vaccinated three times (primary series). Those who remained seronegative after the primary series received a secondary series of vaccinations. Patient baseline characteristics and treatment details from the medical records were retrospectively investigated. The proportion of patients that was seropositive for HB virus antibody after primary-and secondary series of vaccinations was calculated. Associations between immunosuppressants and serostatus were evaluated.

RESULTS

Fifteen of 26 patients (58%) produced anti-hepatitis B surface antibody (anti-HBs) after the primary vaccinations. Eight of 10 patients (80%) taking methotrexate and 3 of 11 (27%) taking mycophenolate mofetil (MMF) were seropositive. Multivariate analysis adjusted for dosage of prednisolone per body weight. Multivariate analysis showed MMF was a factor impeding seroconversion (odds ratio 0.093, 95% confidence interval 0.014-0.615). In six of seven patients (86%) who received a secondary series of vaccinations, anti-HBs were produced.

CONCLUSIONS

MMF may impede seroconversion after a primary series of HB vaccinations, thus requiring secondary series of vaccinations in pediatric patients with a rheumatic disease undergoing immunosuppressive therapy.

Risk factors of the efficacy of hepatitis B vaccine in health-care workers

Background

Conventional hepatitis B virus vaccination fails to achieve efficient protection in about 5%-10% of the world population. Different factors influence the immunogenicity of hepatitis B vaccine. This study aimed to evaluate these factors in health-care workers.

Materials and Methods

This was a descriptive study which was implemented among 140 of medical and dental staff working as health-care workers who were low responder after vaccination entered the study.

Results

Age (>40 years), weight (body mass index >25), immunodeficiency diseases, (primary immune deficiency and immunosuppressant drugs), diabetes mellitus, and smoking were the important factors.

Conclusion

In the high-risk group of hepatitis B disease, the risk factors of immunogenicity must be evaluated at vaccination and check titers of antibody after vaccination.

Protective immunity against hepatitis B virus infection in a group of vaccinated Sri Lankan military service men following a complete course of vaccination

Vaccination is the appropriate measure to protect military personnel against the hepatitis B virus (HBV) infection. Testing the military personnel for anti-HBs levels after vaccination is vital in re-vaccinating those that have not developed protective immunity. The aim of the current study was to determine the immunity in a group of vaccinated Sri Lankan military personnel (n = 150; age = 26-44 years) following a complete course of hepatitis B virus surface antigen (HBsAg) vaccination by assessing the antibodies against HBsAg (anti-HBs) levels. Three months after the last dose of the vaccination, blood samples were collected from the study population and tested for anti-HBs levels using a commercially available ELISA. Of the 150 military service men tested, 139 (92.67%) had anti-HBs levels higher than 10 mIU/mL, WHO approved levels for protective immunity against HBV infection. Of the 139 that had sufficient anti-HBs levels, 24% (36/150) had anti-HBs levels between 10 and 100 mIU/mL and 68.67% (103/150) had anti-HBs levels > 100 mIU/mL. Overall, 7.33% (11/150) participants had anti-HBs levels < 10 mIU/mL. Sero-conversion to > 10 mIU/mL anti-HBs was more than 90% in those that were less than 40 years of age and it was less than 90% in those that were more than 40 years of age.

Evaluation of a hepatitis B virus protection intervention among interns at Zagazig University Hospitals, Egypt

BACKGROUND

Hepatitis B virus (HBV) infection is the most common serious liver infection. The study aimed to evaluate the effect of a HBV protection intervention on interns, as regards their knowledge, attitude and immune response to HB vaccine and to identify the factors affecting their compliance and immune response to HB vaccination at Zagazig University Hospitals.

METHODS

A quasi-experimental study was conducted in 3 phases over 10 months. Phase 1: assessment of knowledge, attitude and HCV/HBV immune status. Phase 2: the implementation of HBV protection campaign; vaccine administration and health education sessions. Phase 3: the assessment of the immune response to the vaccine and the change in knowledge and attitude.

RESULTS

Out of 120 participants, 60% were compliant to the vaccination schedule. Needle-stick injury, the seriousness of HBV infection and attendance of infection control courses are the motivating factors to vaccination (p < 0.05). After the 3rd dose, 9.7% were non-responders. BMI and diabetes were the statistically significant predictors of the immune response. The HCWs compliant with vaccination schedule had higher mean scores regarding; total knowledge (15.5 ± 2.1), p < 0.0001 and attitude (14.34 ± 3.8) p < 0.05. A significant improvement is recorded from the posttest results, p < 0.000.

CONCLUSIONS

A comprehensive protective program against HBV is an effective tool. A compulsory vaccination program is still needed for interns. Post vaccination monitoring program, including protective measures for vaccine non responders is urgently needed with strict follow up of at risk groups. Occult HBV cases should not be overlooked when screening for immune response to vaccine.

Ethnicity and response to primary three-dose hepatitis B vaccination in employees in the Netherlands, 1983 through 2017

BACKGROUND AND AIMS

Hepatitis B virus (HBV) vaccination is recommended to all employees who have an occupational risk in the Netherlands. This study assessed the determinants of the immune response to primary standard three-dose HBV vaccination (0, 1, 6 months), with the main focus on ethnicity.

METHODS

Out of 76 239 individuals who received HBV vaccination between April 1983 and December 2017, 11 567 persons with a known country of birth and complete vaccination schedule were included in this study. Weighted multiple logistic regression with Firth's bias adjustment was used to assess the determinants of nonresponse (anti-HBs < 10 mIU/mL) and low response (anti-HBs 10-99 mIU/mL).

RESULTS

Baseline characteristics of the study population (n = 11 567) were as follows: mean age 27.5 years (95% confidence interval [CI], 27.23-27.72), 99.4% born in the Netherlands and 93.5% of Western European origin. Of all identified subjects, 180 (1.6%) were HBV vaccine nonresponders and 549 (4.8%) were low responders. When compared with individuals aged <40 years, the rate of nonresponse (4.3% vs 0.8%; P < .001) and low response (11.9% vs 2.9%; P < .001) was higher in those aged 40 years or older. The height of anti-HBs levels were lower in those subjects aged >40 years in comparison with those younger than 40 years, P < .001. All nonresponders were born in the Netherlands. Although no significant association was found between nonresponse and individuals of Western European origin (adjusted odds ratio [aOR] = 1.20; 95% CI, 0.66-2.44; P = .163), low response to HBV vaccination was significantly associated with Western European origin (aOR = 2.21; 95% CI, 1.41-3.86; P = .001). Significant determinants for nonresponse were older age at vaccination (aOR = 1.06; 95% CI, 1.06-1.07; P < .001) and male gender (aOR = 2.51; 95% CI, 1.97-3.22; P < .001).

CONCLUSIONS

The nonresponse rate was low in our study population. Our findings suggest that the vaccines being used for the primary vaccination are probably less immunogenic for older individuals, males, and persons of Western European origin.

Post Hepatitis B vaccination sero-conversion among health care workers in the Cape Coast Metropolis of Ghana

Background

HBV vaccine is known to offer protection against transmission of HBV infection. Health care workers are mandated to have this vaccination as part of their occupational health safety measures. Post vaccination response data for HCWs in our setting is not available. This study therefore aimed to evaluate the anti-HBs titre levels after Hepatitis B vaccination among HCWs from selected heath facilities in the Cape Coast Metropolis, Ghana.

Methods

A multicenter (3 selected sites) analytical cross-sectional study involving 711 HCWs was conducted. Five (5mls) of blood samples were collected from each study participant and the serum used for HBV immunological profile testing anti-HBs quantification by ELISA test (Fortress Diagnostics Limited, Northern Ireland, United Kingdom). Data analyses were performed using Stata version 14.0 software (STATA Corp, Texas USA).

Results

The median age of participants was 29 years (IQR = 26–35 years). Majority (80.9%, n = 575) took their vaccination from Government health facilities compared with 19.1% (n = 136) from private vaccination sources. A total of 7 (3 males and 4 females) were found to be HBsAg positive giving prevalence of 1%. In all, 8.2% (n = 58) of the HCWs had anti-HBs titre levels <10IU/ml giving a sero-protection rate of 91.8%. HCWs who received 3 doses of HBV vaccine were more likely to be sero-protected as compared to those who received only one dose in multivariate analysis (aOR = 3.39, 95%CI: 1.08–10.67), p<0.037). Gender, cigarette smoking and alcohol consumption were not found to be associated with sero-protection.

Conclusion

There is a high HBV vaccine efficacy among HCWs in the Cape Coast Metropolis of Ghana with higher prevalence of anti-HBs titre level associated with full vaccine dose adherence. Post vaccination antibody titre determination could be an integral part of HBV vaccination protocol for HCWs in Ghana.

Evaluation of immune response to hepatitis B vaccine in healthcare workers at a tertiary care hospital

Purpose

Healthcare workers (HCWs) are at high risk of acquiring hepatitis B virus (HBV) infection through occupational exposure which is preventable through hepatitis B vaccination. In the current study, the response to HBV surface antigen (HBsAg) vaccine was assessed in a selected group of HCWs by testing for antibodies against HBsAg (anti-HBs).

Methods

Blood samples were collected in all HCWs, who have received the complete schedule of hepatitis B vaccination and anti-HBs levels, were assessed quantitatively in sera using ELISA.

Results

The age range of the study participants was 20-55 years. The mean months after the last dose of vaccination were 60.36. Among the 85 participants, 96.5% (n = 82) have protective immunity to hepatitis B. The anti-Hbs response was similar in both male and female (P > 0.05). There was a decline in immune response as the age was increasing (P < 0.05). The results of the study found a significant decline in the immune response with time (P < 0.05). The anti-Hbs response was declined with smoking habit (P < 0.05) and with increasing body mass index (P < 0.05).

Conclusion

Post-HBsAg vaccination immunity to hepatitis B was 96.5% in HCW and was similar to that of global rates. Increasing age, time period, smoking habit, and overweight were associated with decreased immunity. Many studies are needed in developing newer HBV vaccines with very high immunogenicity. Giving highly immunogenic vaccine to HCWs will ensure safety at work by reducing nosocomial transmission which is very much desired in a resource-limited country.

Hepatitis B vaccination coverage among healthcare workers at a tertiary hospital in Rwanda

OBJECTIVE

We evaluated post-vaccination immunity status and describe potential risk factors associated with the lack of response among healthcare workers (HCWs) at a tertiary care hospital in Kigali, Rwanda.

RESULTS

Of 373 HCWs, 291 (78.2%) were female and 81 (21.8%) were male. The mean age of the study participants was 40.2 years (standard deviation [SD], 7.7 years), within a range of 24-41 years. Participants' mean BMI was 25.4 ± 6.6 kg/m², with more than half of patients (60.3%) being overweight. 96% received all three doses of vaccination. A total of 36 participants (9.6%) were considered non responders as they did not develop a sufficient anti-HBs response post vaccination. The anti-HBs response was significantly higher in females when compared to males (p = 0.02). Interestingly, there was no significant association between decline in antibody levels with age (p = 0.242) and BMI (p = 0.516) of the participants. The anti-HBs titers were similar in the group of participants who had received two doses and those who had received three doses of the HBV vaccination. Overall the findings of our study provide a basis for testing for anti-HBs in all HCWs post vaccination in Rwanda.

Decrease in Anti-HBs Antibodies over Time in Medical Students and Healthcare Workers after Hepatitis B Vaccination

Background

Hepatitis B is one of the most important occupational hazards among healthcare workers (HCWs). This study aimed to measure the anti-HBs titres among the medical students and HCWs vaccinated against hepatitis B virus and to determine the association between anti-HBs levels and time since vaccination.

Materials and Methods

In this cross-sectional study, medical students and healthcare workers who had received all three doses of hepatitis B vaccination and completed at least six months after vaccination since the last dose were included. 3 ml blood was collected from subjects (n = 340) and anti-HBs titre was estimated using ELISA.

Results

A total of 340/400 subjects were aged between 18 and 60 years; 204 were females and 136 males. The median and interquartile range for time since vaccination were 5 and 5 years, respectively. Duration since vaccination was ≤5 years in 223 (65.5%), 6–10 years in 84 (24.7%), and >10 years in 33 (9.70%); among them, antibody titres were >10 mIU/ml in 94.1%, 79.7%, and 72.7% subjects, respectively. There was significant decline in antibody titres as duration of postvaccination increased.

Conclusion

The proportion of subjects who were unprotected after 5 and 10 years after vaccination were 20% and 27%, respectively. The need for a booster dose can be made mandatory at least for healthcare professionals.

Low Immunogenicity of Recombinant Hepatitis B Vaccine Derived from Hansenula polymorpha in Adults Aged Over 40 Years

The Brazilian recombinant hepatitis B vaccine (VrHB-IB) is based on the expression of the recombinant antigen in Hansenula polymorpha yeast cells. Currently, data on the immunogenicity of this vaccine in older adults are nonexistent. This study aimed to evaluate the immunogenicity of VrHB-IB in adults over 40 years of age. From May to October 2011, 235 rural settlers between 2 and 93 years of age from the State of Goias in Brazil were eligible for vaccination. Of these, 180 accepted the first dose of the vaccine and 106 (58.9%) completed the vaccination schedule. Multivariate analysis revealed that individuals ≥ 40 years of age responded significantly less well to vaccination than younger adults. Also, a greater proportion of male nonresponders was observed (versus women; P = 0.02). These results point to the need for better evaluation of the immunogenicity of VrHB-IB in older adults.

Immunogenic and protective efficacy of recombinant protein GtxA-N against Gallibacterium anatis challenge in chickens

Gallibacterium anatis is a major cause of reproductive tract infections in chickens. Here, we aimed to evaluate the efficacy of the recombinant protein GtxA-N at protecting hens, by addressing three objectives; (i) evaluating the antibody response following immunization (ii) scoring and comparing lesions, following challenge with G. anatis, in immunized and non-immunized hens and (iii) investigating if the anti-GtxA-N antibody titre in individual hens correlated with the observed lesions. Two consecutive experiments were performed in hens. In the first experiment hens were immunized with GtxA-N on day 0 and day 14, infected with G. anatis on day 28 and euthanized on day 56. The GtxA-N antibody response was assessed in pooled serum samples throughout the experiment, using an indirect enzyme-linked immunosorbent assay (ELISA). In the second experiment the GtxA-N antibody titres were assessed in individual hens before and after immunization. Subsequently, the hens were inoculated with G. anatis and finally all hens where euthanized and submitted for post mortem examination 48 h after inoculation. Immunization elicited strong antibody responses that lasted at least 8 weeks (P < .0001). The individual antibody titres observed in response to immunization varied considerably among hens (range: 174,100-281,500). Lesion scores following G. anatis infection were significantly lower in immunized hens compared to non-immunized hens (P = .004). Within the immunized group, no correlation was found between the individual antibody titres and the lesion scores. This study clearly demonstrated GtxA-N as a vaccine antigen able of inducing protective immunity against G. anatis.

Effects of hepatitis B vaccine boosters on anti-HBs-negative children after primary immunization

This study was aimed at evaluating the changes of hepatitis B surface antibody (anti-HBs) titer after booster vaccinations in 5-15-year-old children with negative antibodies (<10 mIU/mL). 225 subjects (mean age, 9.28 ± 2.95 years) included in the study consisted of 123 males and 102 females, with a complete hepatitis B vaccination during infancy. The participants were divided into 3 groups according to their pre-booster anti-HBs level: Group I, <0.1 mIU/mL; Group II, 0.1 to <1.0 mIU/mL; Group III, 1.0 to <10.0 mIU/mL. All the participants were administered 3 doses of booster hepatitis B vaccination (0-1-6 month, 20 µg), and changes in the levels of antibodies were examined at 4 time-points (one month after the first and the third dose, one year and 5 years after the third dose). The seroprotective rate (defined as anti-HBs ≥10.0 mIU/mL) among 225 subjects at the 4 time-points were 93.8%, 100%, 83.6% and 73.4%, respectively (χ² = 90.29, p < 0.05). The seroprotective rate (≥10 mIU/mL) and anti-HBs geometric mean titer (GMT) in Group III were always higher than those in the other 2 groups (all p < 0.05). The immune effect of a 3 -dose booster revaccination is good, and the booster-induced immune response was correlated with the pre-booster titer level, and ≥1.0 mIU/mL ensuring a robust positive response, whereas titers below this value may indicate the need for a course of booster vaccination.

Factors influencing immunologic response to hepatitis B vaccine in adults

Hepatitis B was still a worldwide health problem. This study aimed to conducted a systematic review and meta-analysis to assess a more precise estimation of factors that influence the response to hepatitis B vaccine in adults. Our included studies examined seroprotection rates close to the end of vaccination schedules in healthy adult populations. This meta-analysis including 21053 adults in 37 articles showed that a significantly decreased response to hepatitis B vaccine appeared in adults (age ≥ 40) (RR:1.86, 95% CI:1.55–2.23), male adults (RR:1.40, 95% CI:1.22–1.61), BMI ≥ 25 adults (RR:1.56, 95% CI:1.12–2.17), smoker (RR:1.53, 95% CI:1.21–1.93), and adults with concomitant disease (RR:1.39, 95% CI:1.04–1.86). Meanwhile, we further found a decreased response to hepatitis B vaccine appeared in adults (age ≥ 30) (RR:1.77, 95% CI:1.48–2.10), and adults (age ≥ 60) (RR:1.30, 95% CI:1.01–1.68). However, there were no difference in response to hepatitis B vaccine both in alcoholic (RR:0.90, 95% CI:0.64–1.26) and 0-1-12 vs. 0-1-6 vaccination schedule (RR:1.39, 95% CI:0.41–4.67). Pooling of these studies recommended the sooner the better for adult hepatitis B vaccine strategy. More vaccine doses, supplemental/additional strengthening immunity should be emphasized on the susceptible population of increasing aged, male, BMI ≥ 25, smoking and concomitant disease. The conventional 0-1-6 vaccination schedule could be still worth to be recommended.

Immune Responses to Single-Dose Versus Double-Dose Hepatitis B Vaccines in Healthcare Workers not Responding to the Primary Vaccine Series: A Randomized Clinical Trial

BACKGROUND

Recommendations to immunize healthcare workers (HCWs) against hepatitis B are well known. However, a proportion of individuals do not respond to the primary standard three-dose HB vaccination schedule.

OBJECTIVES

The current study aimed to evaluate whether a double-dose HB booster vaccine could induce better protective anti-HB titers than a single-dose booster in non-protected HCWs.

MATERIALS AND METHODS

This was a randomized clinical trial. A total of 91 HCWs not responding to the primary vaccine series in 2014 were enrolled. The participants were randomized into two groups that received a double dose of the HB vaccine containing 40 µg of antigen or a single dose of the HB vaccine containing 20 µg of antigen in three doses (at zero, one and six months after vaccination). Blood samples were collected before vaccinations and 28 days after the third dose to assess the seroconversion rate, according to the anti-HB antibody titer threshold of > 10 mIU/mL.

RESULTS

The seroconversion rates were 93.2% and 87.2% after the first booster doses of the double-dose and single-dose HB vaccines, respectively (P = 0.64). In the double-dose HB vaccine group, the seroconversion rate was 97.8% compared with 89.6% in the single-dose group following the second vaccine dose (P = 0.83). All of the participants in both groups were seroprotected after the third HB vaccine dose.

CONCLUSIONS

Both the single- and double-dose HB vaccines were adequately immunogenic, and the double-dose HB vaccine was not significantly more immunogenic than the single-dose vaccine in terms of the seroconversion rates of HCWs who had not responded to the primary vaccine series.

Prevalence of hepatitis B virus infection among health care workers in a tertiary hospital in Tanzania

Background

Sub-Saharan Africa has a high prevalence of hepatitis B virus (HBV) infections. Health care workers (HCWs) are at high risk of contracting HBV infection through their occupation. Vaccination of HCWs against HBV is standard practice in many countries, but is often not implemented in resource-poor settings. We aimed with this cross-sectional study to determine HBV prevalence, HCW vaccination status, and the risk factors for HCWs contracting HBV infection in Tanzania.

Methods

We enrolled 600 HCWs from a tertiary Tanzanian hospital. Their demographics, medical histories, HBV vaccination details and risk factors for contracting blood-borne infections were collected using a standardized questionnaire. Serum samples were tested for HBV and hepatitis C virus (HCV) markers by ELISA techniques, PCR and an anti-HBs rapid test. HCWs were divided in two subgroups: those at risk of contracting HBV (rHCW 79.2 %) via exposure to potentially infectious materials, and those considered not at risk of contracting HBV (nrHCW, 20.8 %).

Results

The overall prevalence of chronic HBV infection (HBsAg+, anti-HBc+, anti-HBs-) was 7.0 % (42/598). Chronic HBV infection was found in 7.4 % of rHCW versus 5.6 % of nrHCW (p-value = 0.484). HCWs susceptible to HBV (HBsAg-, anti-HBc-, anti-HBs-) comprised 31.3 %. HBV immunity achieved either by healed HBV infection (HBsAg-, anti-HBc+, anti-HBs+) or by vaccination (HBsAg-, anti-HBc-, anti-HBs+) comprised 36.5 % and 20.2 %, respectively. 4.8 % of participants had indeterminate results (HBsAg-, anti-HBc+, anti-HBc-IgM-, anti-HBs-). Only 77.1 % of HCWs who received a full vaccination course had an anti-HBs titer >10 ml/U. An anti-HBs point-of-care test was 80.7 % sensitive and 96.9 % specific. There was a significantly higher risk for contracting HBV (anti-HBc+) among those HCW at occupational risk (rHCW) of older age (odds ratios (OR) in rHCW 3.297, p < 0.0001 vs. nrHCW 1.385, p = 0.606) and among those HCW being employed more than 11 years (OR 2.51, p < 0.0001***). HCV prevalence was low (HCV antibodies 1.2 % and HCV-RNA 0.3 %).

Conclusions

Chronic HBV infection is common among Tanzanian HCWs. One third of HCWs were susceptible to HBV infection, highlighting the need for vaccination. Due to high prevalence of naturally acquired immunity against HBV pre-testing might be a useful tool to identify susceptible individuals.

Hepatitis B virus infection: An insight into infection outcomes and recent treatment options

Hepatitis B virus (HBV) currently infects an estimated population of 2 billion individuals in the world, including 400 million people with chronic HBV infection. HBV virology, replication and the host's immune response to HBV infection contribute to different infection outcomes. Acute hepatitis HBV infection is self-limiting but it leaves a residual infection that can become active in an individual during immunosuppression. In chronic HBV infection, the virus persistently replicates in hepatocytes leading to immune mediated hepatocellular damage. Despite the inability to remove the virus in more than 70 % of patients, current treatments for chronic HBV infection, interferon alpha and antiviral nucleotide/nucleoside analogues, aim to reduce viral replication to prevent or at least delay the progression to cirrhosis and hepatocellular carcinoma. In both self resolved acute and persistent HBV infection, the long term existence of chromatinised covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes cannot be targeted by current treatments to eliminate these templates to eradicate the viral persistence. Identifying the mechanisms involve in the removal of infected hepatocytes will be useful as treatment options. In this context, DNA based novel therapeutic and immunization strategies might help to remove stable cccDNA and thus viral persistence.

Post-vaccination Immunity Against Hepatitis B Virus and Predictors for Non-responders Among Medical Staff

BACKGROUND

Hepatitis B virus (HBV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). HB vaccination is an essential step in the prevention of the disease and its consequent complications.

OBJECTIVES

Immune status of medical personnel in teaching hospitals of Khuzestan is not well known. Since these personnel are usually at risk of needle stick and other high-risk events, some challenges exist in infection control committee with regard to managing these events. This study was conducted to assess post-vaccination immunity status and non-response to HBV vaccine as well as its predictors among medical staff in a teaching hospital affiliated to Ahvaz Jundishapur University of Medical Sciences (AJUMS) in Ahvaz, southwest Iran.

PATIENTS AND METHODS

In this retrospective cross-sectional study, the medical staff of a teaching hospital was evaluated for their immune response against HBV and factors affecting it. The study conducted in Razi Hospital, Ahvaz City, southwest of Iran, in 2013. Demographical, clinical, and laboratory data registered in medical files of hospital staff were analyzed by SPSS software version 16 using chi-square and Fisher exact tests. Differences with P value < 0.05 were considered significant. To identify predictors for non-responders, we used odds ratio (OR) with 95% confidence interval (CI).

RESULTS

Out of 239 participants, 43 (18 %) were men and 196 (82%) were women. Their mean age was 31.9 ± 18.1 years (range of 20 - 55 years). Fourteen (5.9%) participants were non-responders, 37 (15.5%) were poor responders, and 188 (78.6%) were good responders. The non-responders were older (> 50 years) than the responders (P = 0.0001), while the body mass index (BMI) was not significantly different (P = 0.37) between them. Diabetes mellitus (DM) (OR: 7.3, 95% CI, 1.3 - 41.7, P = 0.05), and using immunosuppressive drugs (ISD) (OR: 3.2, 95% CI, 1.1 - 11.5, P = 0.03) were two variables in association with non-response to HB vaccine.

CONCLUSIONS

Non-response rate to HB vaccine in our study was approximately 6%. Age over 50 years, DM, and receiving immunosuppressive drugs may be considered as predictors for non-response to HB vaccine in medical staff.

The effects of different dosage levels of hepatitis B vaccine as booster on anti-HBs-negative children 5-15 y after primary immunization; China, 2009-2010

The changes in lgG antibody levels to hepatitis B surface antigen (HBsAg) and in antibody to HBsAg (anti-HBs) seroconversion rates due to different dosages of hepatitis B vaccine (HepB) were compared in 2106 children. Children who had been previously vaccinated as infants with HepB were revaccinated at 5-15 y of age, after which the antibody titers were determined. After the first booster dose, the anti-HBs seroconversion rate (defined as an anti-HBs ≥10 mIU/ml) with 10 μg of HepB (93.6%) was significantly greater than the rate with 5 µg of HepB (90.3%) (P<0.05); the anti-HBs seroconversion rate in 10-15-y-old boys vaccinated with 10 μg of HepB (90.9%) was significantly greater than the rate with 5 µg of HepB (84.3%) (P<0.05). The anti-HBs seroconversion rates after the third booster dose with 5 or 10 μg of HepB were greater than those after the first booster dose (99.6% and 99.7%, vs. 90.3% and 93.6%, P<0.05); as was the corresponding GMTs (658 ± 4 mIU/ml and 2599 ± 3 mIU/ml, vs. 255 ± 11 mIU/ml and 877 ± 11 mIU/ml [P<0.05]). The immunization effects of booster vaccination with 3 doses of HepB with 5 or 10 µg are effective; a single booster dose with 10 µg of HepB for 10-15-y-old boys and with 5 or 10 µg of HepB for 5-9 y old boys and for 5-15-y-old girls are effective in generating protective antibody against HBV; however, for anti-HBs-negative children after a single dose of booster, 3 doses are needed.