Significance of anti-HB levels below 10 IU/L after vaccination against hepatitis B in infancy or adolescence: an update in relation to sex

Evaluating the benefit of serology during potential Australian bat lyssavirus and rabies post-exposure prophylaxis

Post-exposure prophylaxis (PEP) for potential lyssavirus exposures consists of wound management, rabies vaccination and may include rabies immunoglobulin (RIG). Rabies serology is sometimes indicated if there is risk of PEP failure.

OBJECTIVES

Evaluate the benefit of serology by indication.

METHODS

Chart review of potential lyssavirus exposures managed at a Public Health Unit (June 2015 - December 2022) where serology was requested was conducted. The proportion of non-therapeutic titres was compared by sex, age, Indigenous status, serology indication, and whether RIG was given.

RESULTS

46 notifications with serology were included. Males (5/19) and people over 40 (3/16) were more likely to demonstrate a non-therapeutic response. 2/3 of cases where vaccine doses were not given in the deltoid were non-therapeutic. The rate of non-therapeutic titres was similar for RIG given into the ipsilateral arm (2/11) and given excess RIG for weight (1/4). Although this small sample was inconclusive in isolation, it was also noted that all cases who did not receive RIG had therapeutic serology, whereas 6/35 of those receiving RIG had non-therapeutic serology.

CONCLUSIONS

This study supports broader literature questioning the utility of systemic RIG administration as likely limited and potentially detrimental considering the increased risk of immune interference.

IMPLICATIONS FOR PUBLIC HEALTH

Highlights a need to review Australian national guidelines to align with World Health Organization advice recommending local RIG administration only.

Multi-View Learning to Unravel the Different Levels Underlying Hepatitis B Vaccine Response

The immune system acts as an intricate apparatus that is dedicated to mounting a defense and ensures host survival from microbial threats. To engage this faceted immune response and provide protection against infectious diseases, vaccinations are a critical tool to be developed. However, vaccine responses are governed by levels that, when interrogated, separately only explain a fraction of the immune reaction. To address this knowledge gap, we conducted a feasibility study to determine if multi-view modeling could aid in gaining actionable insights on response markers shared across populations, capture the immune system's diversity, and disentangle confounders. We thus sought to assess this multi-view modeling capacity on the responsiveness to the Hepatitis B virus (HBV) vaccination. Seroconversion to vaccine-induced antibodies against the HBV surface antigen (anti-HBs) in early converters (n = 21; <2 months) and late converters (n = 9; <6 months) and was defined based on the anti-HBs titers (>10IU/L). The multi-view data encompassed bulk RNA-seq, CD4+ T-cell parameters (including T-cell receptor data), flow cytometry data, and clinical metadata (including age and gender). The modeling included testing single-view and multi-view joint dimensionality reductions. Multi-view joint dimensionality reduction outperformed single-view methods in terms of the area under the curve and balanced accuracy, confirming the increase in predictive power to be gained. The interpretation of these findings showed that age, gender, inflammation-related gene sets, and pre-existing vaccine-specific T-cells could be associated with vaccination responsiveness. This multi-view dimensionality reduction approach complements clinical seroconversion and all single modalities. Importantly, this modeling could identify what features could predict HBV vaccine response. This methodology could be extended to other vaccination trials to identify the key features regulating responsiveness.

Immunological Findings in a Group of Individuals Who Were Poor or Non-Responders to Standard Two-Dose SARS-CoV-2 Vaccines

Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared a pandemic. However, data on the poor or non-responders to SARS-CoV-2 vaccines in the general population are limited. The objective of this study was to comprehensively compare the immunological characteristics of poor or non-responders to SARS-CoV-2 vaccines in the 18-59-year group with those in the ≥60-year group using internationally recognized cut-off values. The main outcome was effective seroconversion characterized by an anti-SARS-CoV-2 spike IgG level of at least a four-fold increase from baseline. Profiling of naïve immune cells was analyzed prior to vaccination to demonstrate baseline immunity. The outcomes of effective seroconversion in patients aged 18-59 years with those in patients aged ≥60 years were compared. The quantitative level of anti-spike IgG was significantly lower in individuals aged ≥60 and men aged 18-59 years. There were 7.5% of poor or non-responders among the 18-59 years and 11.7% of poor or non-responders in the ≥60 years using a four-fold increase parameter. There were 37.0-58.1% with low lymphocyte count (<1000/mm³), 33.3-45.2% with low CD4 cell counts (<500/mm³), and 74.1-96.8% with low B cell counts (<100/mm³) in the non-seroconversion group. An individual with an anti-SARS-CoV-2 spike IgG titer below 50 BAU/mL might be considered a poor or non-responder between 14 and 90 days after the last vaccine dose. Booster vaccination or additional protective measures should be recommended to poor or non-responders as soon as possible to reduce disease severity and mortality.

Prevalence of healthcare workers fully vaccinated against hepatitis B without circulating antibodies in Italy and role of age at baseline cycle vaccination: a systematic review and meta-analysis

INTRODUCTION

Healthcare workers (HCWs) susceptible to hepatitis B represent an important public health concern. National and international guidelines recommend assessing the hepatitis B immune status of all HCWs and possibly vaccinating those found to be seronegative (non-responders). We conducted a meta-analysis to estimate the rate of hepatitis B sero-susceptibility among HCWs in Italy and to explore possible options for the management of non-responders.

AREAS COVERED

Nineteen studies, selected from scientific articles available in the Scopus, MEDLINE/PubMed and ISI Web of Knowledge databases between 1 January 2016 and 22 April 2022, were included. The prevalence of HBV-susceptible HCWs was 27.1% (95%CI = 23.2-31.7%). In a comparison by sex (males vs. females) the RR was 1.16 (95%CI = 1.03-1.31), and by full-cycle vaccination period (adolescence vs. infancy) the RR was 0.30 (95%CI = 0.25-0.37). Occupational health screenings for hepatitis B, with subsequent vaccination of non-responders, and exclusion of susceptible HCWs from high-risk settings have been common management strategies.

EXPERT OPINION

It is highly probable that a proportion of the next generation of medical students and HCWs will not show circulating IgG on serologic evaluation. Therefore, more targeted efforts are needed to identify these individuals and actively immunize them.

Factors influencing long-term persistence of anti-HBs after hepatitis B vaccination

Long-term immunity after HBV vaccination is still debated. When assessing immune persistence, several variables must be considered, the clear definition of which is crucial. Our aim was to assess protection 10-20 years after primary vaccination and to estimate the effect of age at first dose, sex and time elapsed between doses on long-term protection. We conducted a retrospective cohort study between January 2004 and December 2020. Antibody titres above 10 IU/L were considered protective. Geometric mean titres (GMT) were calculated. The effect of the above variables on long-term protection was assessed by logistic regression analysis. Included participants were 9459. Among those vaccinated during infancy, GMT gradually increased from 11 IU/L (first dose in 1st trimester of life) to 68 IU/L (4th trimester), while the proportion of individuals <10 IU/L remained stable between 1st and 2nd trimester (51%) and it decreased substantially in 3rd (28%) and even more so in the 4th (18%). A one-month delay in first and third dose administration was correlated with a -16% (AOR: 0.84; 95% CI: 0.78-0.91) and a -11% (AOR: 0.89; 95% CI: 0.85-0.94) risk of a titre <10 IU/L, respectively, ~20 years after immunisation. In contrast, similar changes do not comparably affect vaccination in adolescence. The start of vaccination at the third month of age is a compromise between the development of acceptable immunogenicity and the need to protect the infant as early as possible. However, the chance of slightly delaying the vaccine administration within the first year of life may be considered given the impact on long-term persistence of anti-HBs.

Long-Term Effectiveness of Hepatitis B Vaccination in the Protection of Healthcare Students in Highly Developed Countries: A Systematic Review and Meta-Analysis

Hepatitis B virus represents an important global health problem. In highly developed countries, mass vaccination campaigns of newborns in recent decades have drastically reduced the proportion of carriers. However, workers exposed to blood and body fluids, including healthcare students, can be at risk of exposure. In order to assess the proportion of susceptible individuals in the specific population of healthcare students in highly developed countries, a systematic review and meta-analysis was performed to summarize the evidence on the persistence of humoral immune protection induced by the primary cycle of hepatitis B vaccination, as well as the proportion of true non-responders. Forty-six studies were included in the final analysis (52,749 participants). Overall, the seroprotection prevalence at the pre-exposure assessment was equal to 73.8% (95% CI 69.1-78.0); the prevalence of anamnestic response following the administration of a challenge dose was 90.9% (95% CI 87.7-93.3), demonstrating a high proportion of persistence of vaccination-induced immunity. Among those without evidence of anamnestic response, 5.0% (95% CI 2.1-11.5) were non-responders following the completion of a secondary immunization cycle. These findings demonstrate that the majority of healthcare students vaccinated with the complete HBV primary cycle maintain an effective humoral immunity against this pathogen for over two decades.

Body Mass Index and Antibody Persistence after Measles, Mumps, Rubella and Hepatitis B Vaccinations

Overweight and obesity may cause a reduced response to vaccination. The purpose of the present research was to study the relationship between current body mass index (BMI) and antibody persistence after vaccination against measles, mumps, and rubella (MMR) and hepatitis B virus (HBV) given during childhood, as per the current vaccination schedule. The study was conducted on 2185 students at the School of Medicine, University of Padua, Italy. The mean age of the participants was 20.3 years. After adjusting for sex, age at first dose of vaccine administered, age at last dose, and age at study enrollment, no significant association was found between lack of serologic protection and BMI for either the HBV vaccine or each component of the MMR vaccine. For the first time, the absence of this relationship was demonstrated for the MMR vaccine. Given the evidence currently available, further research on BMI and vaccines in general remains desirable.

Post-vaccination Immunity Against Hepatitis B Among Mongolian Adolescents and Youths

Background: Mongolia introduced vaccination against hepatitis B (HepB) in 1991, leading to a significant decline in the number of infections and mortality associated with the liver disease among this generation. However, the prevalence of hepatitis B virus (HBV) infection and mortality rates among people born before the vaccination program have not declined. Although several studies have been conducted in Mongolia since the introduction of the HepB immunization program, long-term immunity has not been studied at the national level. Objectives: This study aimed to determine the prevalence of HBV infection in adolescents and young adults who received HepB vaccinations at 0, 2, and 8 months after birth and to assess their post-vaccination immunity against hepatitis B. Methods: A population-based cross-sectional study was conducted between December 2016 and December 2018 and included a sample aged 10 to 27 years in Mongolia who had received HepB vaccination according to the national program. A total of 3591 individuals were randomly selected, and data were collected using a structured questionnaire. Blood samples were collected, and serum titers of hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) were determined by a two-step sandwich chemiluminescent enzyme immunoassay. The age-specific geometric mean of anti-HBs was also estimated. Results: Overall, 98.3% of participants were vaccinated against HepB as infants, according to the interview. The majority had an inadequate anti-HBs titer, while 17.9% had an anti-HBs level of > 10 mIU/mL, of whom 5.7% had immunity induced by HBV infection. Up to 4% of children aged 10 - 19 years and an average of 8% of young adults were serologically positive for HBsAg. The geometric mean anti-HBs titer declined with age, from an average of 40.4 mIU/mL in 10-year-old children to 14.1 IU/mL in 27-year-old adults (P < 0.001). Conclusions: In Mongolia, a small proportion of the population aged 10 - 27 years is immune to HBV, and the geometric mean titer of anti-HBS tended to decrease with age. In order to attain long-term protection against HBV, booster vaccination in adulthood may be necessary.

Seroprotection of Hepatitis B Vaccine in Dental Students Two Decades after Infant Immunization and the Possible Need for Revaccination

OBJECTIVES

 This study aimed to assess hepatitis B surface antibody (anti-HBs) persistence among dental students two decades after infant vaccination and immune response after revaccination or booster dose in nonimmune groups.

MATERIALS AND METHODS

 A cross-sectional study was performed using laboratory reports for anti-HBs performed to dental students at the Umm al-Qura University from 2016 to 2020. Reports were classified according to baseline antibody titer into group I (titer <10 mIU/mL), group II (titer 10 to <100 mIU/mL), and group III (titer ≥100 mIU/mL). The basal antibody titer of each group was correlated to student's gender and birth year and compared with postrevaccination or booster dose titer in groups I and II.

STATISTICAL ANALYSIS

 Data of baseline and postrevaccination anti-HBs antibody titers were analyzed using Statistical Package for Social Science (SPSS). One-way ANOVA was used to compare between different means for antibody titers of students as well as baseline and postrevaccination antibody levels for nonimmune students with nonprotective antibody titers. Pairwise multiple comparison of the difference between baseline and postrevaccination anti-HBs antibody titers were done by post hoc Tukey's honestly significant difference (HSD) test. Chi-squared test was used for comparing between the frequencies. A p-Value of ≤0.05 was considered significant and p < 0.01 was considered highly significant.

RESULTS

 A significant percentage (73.6%) of students had antibody titer <10 mIU/mL, while only 4.8% had antibody titer ≥100 mIU/mL with nonsignificant difference between both genders (χ ² =3.784, p = 0.151). A statistically nonsignificant difference was also found between the three categories of anti-HBs antibody titers among students with different birth dates (χ ² = 13.817, p = 0.182). After revaccination of nonimmune students, 100% of them showed strongly protective antibody titers with mean of 842.88 to 844.58 mIU/mL. A highly significant difference was observed between the mean baseline and postrevaccination antibody titers in both genders, with a higher mean of post revaccination (p = 0.000).

CONCLUSION

 Two decades after infant immunization, a significant percentage of dental students failed to maintain the anti-HBs seroprotective titer. So titer measurement should be made compulsory before they begin their clinical training and revaccination or booster dose should be given to nonimmune students to maintain a high protection level.

Rubella Serosurvey Among Future Healthcare Workers

Objective: Rubella is a very diffusive but relatively benign infectious disease unless contracted during pregnancy, when it causes congenital rubella syndrome. The aim of this research was to determine the prevalence and titer of antirubella antibodies in a population of future healthcare workers (students at the school of medicine). Methods: The cohort consisted of 11,022 students who underwent antibody analysis after the presentation of a vaccine certificate. Results: Vaccination compliance was very high, particularly in younger students (born after 1995), reaching almost 100% (at least one dose). Unvaccinated students born before 1990 had high seropositivity (>95%), but this percentage dropped to zero among the youngest students. Variables affecting antibody titer included year of birth and sex. Considering only vaccinated students, a greater antibody response was observed if the vaccine was administered between 8 and 10 years of age. Female sex was associated with more significant (p < 0.0001) positivity and higher antibody titer after one and two doses. However, this difference appeared less consistent in relation to year of birth. Conclusions: The studied population exhibited excellent vaccination compliance, high seropositivity, and high antibody titer. Vaccine and immune coverage were higher than what is deemed necessary to achieve herd immunity.

Requirement for further validation on the seroconversion of hepatitis B surface antigen in successful vaccinees

Hepatitis B vaccination can provide long-term protection against transmission of hepatitis B virus (HBV). An article recently published in Human Vaccine & Immunotherapeutics reported that 3.5% (5/143) of the individuals who had been successfully vaccinated against hepatitis B at infancy became positive for hepatitis B surface antigen (HBsAg) at their young adulthood during a period of four years, indicating that hepatitis B vaccination appears to have no long-term protection. We concern on the exceptional results in that article since the critical data are lacking, questionable, or very implausible. We consider that any exceptional data should be validated as far as possible before the data are used to obtain a conclusion.

Future Healthcare Workers and Hepatitis B Vaccination: A New Generation

Before the introduction of universal vaccination, hepatitis B caused high morbidity and mortality, especially among healthcare workers. In the present study, the immune status against hepatitis B was assessed in a cohort of 11,188 students of the degree courses of the School of Medicine of the University of Padua (Italy) who had been subjected to mandatory vaccination in childhood or adolescence and who will be future healthcare workers. The variables that influence the antibody response to vaccination are mainly the age at which the vaccine was administered and sex. If vaccination was administered before one year of age, there is a high probability (around 50%) of having an antibody titer lower than 10 IU/L compared to those vaccinated after one year of age (12.8%). The time between vaccine and analysis is not decisive. Furthermore, female sex, but only if vaccination was administered after one year of age, shows a significant (p = 0.0008) lower percentage of anti-HBs below 10 IU/L and a greater antibody titer (p < 0.0001). In conclusion, the differences related to the age of vaccination induce more doubts than answers. The only plausible hypothesis, in addition to the different immune responses (innate and adaptive), is the type of vaccine. This is not easy to verify because vaccination certificates rarely report it.

Response to Vaccination against Mumps in Medical Students: Two Doses Are Needed

Mumps is a vaccine-preventable infectious disease diffuse worldwide. The implementation of mumps vaccination reduced largely the spread of infection. On 11,327 Medical School students the prevalence of mumps positive antibodies was evaluated according to dose/doses of vaccine, year of birth and sex. Compliance to mumps vaccine was low in students born before 1990 but increased consistently after this year, above all compliance to two doses, due to the implementation of the vaccine offer. Positivity of mumps antibodies is significantly (p < 0.0001) lower in students vaccinated once (71.2%) compared to those vaccinated twice (85.4%). In addition, students born after 1995, largely vaccinated twice, showed a seropositivity near to 90%. Further, females had a significantly (p < 0.0001) higher proportion of positive antibodies after vaccination than males, both one (74.6% vs. 64.7%) and two doses (86.8% vs. 82.9%). Finally, seropositivity after two vaccine doses remains high (86.1%) even 15 years after the second dose. In conclusion, the research highlighted that vaccination against mumps reaches a good level of coverage only after two doses of vaccine persisting at high levels over 15 years and induces a more significant response in females.

HLA-DPB1 alleles in hepatitis B vaccine response: A meta-analysis

BACKGROUND

The role of the HLA-DRB1 and HLA-DQB1 genes in the antibody response to hepatitis B (HB) vaccine has been well established; however, the involvement of the HLA-DPB1 allele in the HB vaccine immune response remained to be clarified by a systematic review.

METHODS

A meta-analysis was performed in which databases were searched for relevant studies published in English or Chinese up until June 1, 2020. Six studies were identified and a total of 10 alleles were processed into statistical processing in this meta-analysis.

RESULTS

Three thousand one hundred forty four subjects (including 2477 responders and 667 non-responders) were included in this research. Alleles HLA-DPB1∗02:02, DPB1∗03:01, DPB1∗04:01, DPB1∗04:02, and DPB1∗14:01 were found to be associated with a significant increase in the antibody response to HB vaccine, and their pooled odds ratios (ORs) were 4.53, 1.57, 3.33, 4.20, and 1.79, respectively; whereas DPB1∗05:01 (OR = 0.73) showed the opposite correlation.

CONCLUSIONS

These findings suggested that specific HLA-DPB1 alleles are associated with the antibody response to HB vaccine.

Persistence of Anti-Hbs after up to 30 Years in Health Care Workers Vaccinated against Hepatitis B Virus

The burden of hepatitis B virus (HBV) infection is a serious public health problem all over the world. Vaccination remains the most effective prevention measure, and safe and effective HBV vaccines have been available since 1982. Health care workers (HCWs) vaccinated against HBV and prospectively followed up for at least 14 years were classified by their antibody titers after primary vaccination as: poor responders (10–99 mIU/mL); moderate responders (100–999 mIU/mL); and good responders (≥1000 mIU/mL). The incidence of antibody loss was calculated for 1000 person-years and the anti-HBs persistence was calculated. The analysis concerned 539 HCWs: 494 good responders (91.7%); 37 moderate responders (6.9%); and eight poor responders (1.5%). The incidence of anti-HBs loss was 52.1 per 1000 person-years for the poor responders, 11.3 per 1000 person-years for the moderate responders, and 1.4 per 1000 person-years for the good responders. The mean persistence of anti-HBs differed significantly between the three groups, being: 19.2 years (95% CI: 15.6–22.8), 25.4 years (95% CI: 23.0–27.9), and 31.0 years (95% CI: 30.5–31.5) for the poor, moderate and good responders, respectively. In conclusion, our findings demonstrate a good persistence of protective anti-HBs titers in HCWs exposed to occupational risk for up to 30 years after a primary vaccination cycle (even without a booster dose) if their titer was initially higher than 100 mIU/mL.

Sex Disparity in Response to Hepatitis B Vaccine Related to the Age of Vaccination

Hepatitis B virus (HBV) infection is one of the major infectious hazards for health-care workers (HCWs) because of the frequency of percutaneous exposures to blood or body fluids. For this reason, all HCWs should be vaccinated, including students in medicine and health professional degree programs. The aim of this study was to assess the immune coverage to anti-HBV vaccine and long-lasting protective titres of anti-HBs antibodies in female and male students to evaluate gender-related differences in response to HBV vaccination. Data relative to anti-HBs antibody titre, sex, age, and age at vaccination were collected and analyzed from 5291 Italian students (1812 males and 3479 females) of the graduate courses at the School of Medicine, who underwent the mandatory health surveillance of workers exposed to biological risk. The results indicated that gender affects the immune response to HBV vaccine, particularly evident in the case of females vaccinated after one year of age who exhibited a statistically significant (p = 0.0023) 1.21-fold increase in median antibody titre with respect to males. Our findings could contribute to the optimization of HBV vaccination schedules in health surveillance of HCWs.