HBV seroprevalence after 25 years of universal mass vaccination and management of non-responders to the anti-Hepatitis B vaccine: An Italian study among medical students

Anti-HBs Levels 18-26 Years After the Initial Hepatitis B Vaccination Series in a Low-to-Medium Prevalence Region: Is a Booster Dose or a Second Vaccine Series Necessary?

This cross-sectional study aimed to evaluate the persistence of immunity provided by hepatitis B (Hep B) vaccine 18-26 years after primary vaccination among 628 participants. Blood samples were collected for Hep B surface antigen (HBsAg), anti-HBs antibody (anti-HBs), and core antibody (anti-HBc) analyses. For participants with anti-HBs levels of < 10 mIU/mL, booster dose was administered and anti-HBs titers were monitored 4-6 weeks after vaccination was completed. If the response to Hep B vaccine was inadequate, two additional Hep B vaccine doses were administered. Of the 628 participants, 269 were excluded based on the exclusion criteria, and 359 were included in the final analysis. Three participants were found to be HBsAg-positive, resulting in an HBsAg carrier rate of 0.83%. Moreover, 55.4% participants had anti-HBs levels of ≥ 10 mIU/mL, with a geometric mean concentration (GMC) of 82.59 mIU/mL (95% confidence interval [CI]). Among 125 participants with anti-HBs levels of < 10 mIU/mL, 93.1% reached anti-HBs levels of ≥ 10 mIU/mL after booster dose, with a GMC of 493.47 mIU/mL. A prebooster anti-HBs cutoff level of 1.28 mIU/mL was predictive for an immune response, with a sensitivity and specificity of 71.2% and 71.4%, respectively (p = 0.001, 95% CI, likelihood ratio: 2.49). Among 14 participants unresponsive to the booster dose, 78.5% responded to the second vaccine series with a GMC of 670.82 mIU/mL. Approximately 44.6% of participants required a booster dose 18-26 years after primary vaccination. Prebooster anti-HBs titration may predict the response to booster doses. Further studies with larger groups are needed to confirm these findings.

Increasing Prevalence of Occult HBV Infection in Adults Vaccinated Against Hepatitis B at Birth

BACKGROUND/OBJECTIVES

Immunization with the hepatitis B vaccine is the most effective means of preventing acute HBV infection. However, whether the primary vaccination of infants confers lifelong immunity remains controversial. Therefore, the ongoing surveillance of vaccine recipients is required.

METHODS

A longitudinal study was carried out based on LongAn county, one of the five clinical trial centers for hepatitis B immunization in China in the 1980s. Serum samples were collected and tested for HBV serological markers and DNA.

RESULTS

A total of 637 subjects born in 1987-1993 were recruited, including 503 males and 134 females. The total prevalence of HBsAg was 3.9%. The prevalence in females (8.2%) was significantly higher than that in males (2.8%) (p = 0.004). The prevalence of anti-HBc in females (52.2%) was also significantly higher than that in males (41.2%) (p = 0.021). The prevalence of anti-HBs was 42.7% and did not differ significantly between males (41.7%) and females (46.3%) (p = 0.347). Compared to data from surveillance over the last ten years, the positivity rate of HBsAg did not increase. The positivity rate of anti-HBs decreased significantly (p = 0.049) while that of anti-HBc increased significantly (p = 0.001). The prevalence of occult HBV infection (OBI) in 2024 (6.0%) was significantly higher than that in 2017 (1.6%) (p = 0.045). Subjects diagnosed with OBI in 2017 maintained occult infection in 2024.

CONCLUSIONS

Neonatal HBV vaccination maintained effective protection for at least 37 years. However, the prevalence of OBI increases with age in those vaccinated at birth, raising a new issue of how to prevent and control OBI in the post-universal infant vaccination era.

Efficacy of HBV booster dose administration in Italian medical students in relation to health determinants

We evaluated the efficacy of a booster dose of HBV in Italian medical students. We conducted a prospective observational study in students who had received a full course of anti-HBV vaccination for at least 15 y. Those with an anti-HBs titer <10 mIU/mL were offered a booster dose of the HBV vaccine and the antibody titer was reevaluated after 1 month. The participants were classified into three categories: with anti-HBs titer >100 mIU/mL, between 10 and 100 mIU/mL and <10 mIU/mL. The study population was n. 625 medical student and 355 (56.8%) with anti HBs titer <10 mIU/mL were offered a booster dose. A total of 166 of them received the booster dose and 92.77% (38 + 116/166) achieved an anti-HBs titer ≥10 mIU/mL. The post-booster anti-HBs titer response was higher, i.e. >100 mIU/mL, in subjects who had a pre-booster anti-HBs titer between 1.00 and 9.99 mIU/mL (84.38%, 81/96), compared to those with titer <1 mIU/mL (50.00%, 35/70). Subjects with a titer <1.00 mIU/mL at enrollment showed no anamnestic response (post-booster anti-HBs <10 mIU/mL, RRR 0.23, 95% CI 0.06-0.84) and to a low anamnestic response (post-booster anti-HBs 10-100 mIU/mL, RRR 0.16, 95% CI 0.07-0.38). Physical activity was linked to a better antibody response to vaccination (post-booster anti-HBs 10-100 mIU/mL: RRR 2.39, 95% CI 1.05-5.59). Immune protection following primary vaccination against HBV tends to wane over time. Booster dose induces anamnestic responses, especially in individuals who maintain titer HBsAg >1 mIU/mL and do physical activity.

Persistence of antibodies 5 years after hepatitis B vaccination in preterm birth children: A retrospective cohort study using real-world data

Previous studies did not provide substantial evidence for long-term immune persistence after the hepatitis B vaccine (HepB) in preterm birth (PTB) children. Consequently, there is ongoing controversy surrounding the booster immunization strategy for these children. Therefore, we conducted a retrospective cohort study to evaluate the disparities in immune persistence between PTB children and full-term children. A total of 1027 participants were enrolled in this study, including 505 PTB children in the exposure group and 522 full-term children in the control group. The negative rate of hepatitis B surface antibody (HBsAb) in the PTB group was significantly lower than that in the control group (47.9% vs. 41.4%, p = .035). The risk of HBsAb-negative in the exposure group was 1.5 times higher than that in the control group (adjusted odds ratio [aOR] = 1.5, 95% confidence interval [CI]: 1.1-2.0). The geometric mean concentration (GMC) of HBsAb was much lower for participants in the exposure group compared to participants in the control group (9.3 vs. 12.4 mIU/mL, p = .029). Subgroup analysis showed that the very preterm infants (gestational age <32 weeks) and the preterm low birth weight infants (birth weight <2000 g) had relatively low GMC levels of 3.2 mIU/mL (95% CI: 0.9-11.1) and 7.9 mIU/mL (95% CI: 4.2-14.8), respectively. Our findings demonstrated that PTB had a significant impact on the long-term persistence of HBsAb after HepB vaccination. The very preterm infants (gestational age <32 weeks) and the preterm low birth weight infants (birth weight <2000 g) may be special populations that should be given priority for HepB booster vaccination.

Vaccine-preventable diseases: Immune response in a large population of healthcare students

BACKGROUND

Students in medicine and other health professions are exposed to numerous occupational hazards, primarily biological hazards, during their academic careers at university. The aim of the present study was to investigate the seroprevalence characteristics of anti-HBsAg, anti-Measles, anti-Mumps, anti-Rubella and anti-Varicella IgG antibodies in healthcare students of a large teaching hospital in Rome.

METHODS

To accomplish the study's aims, antibody serology data were gathered from students of Medicine and Surgery, Dentistry, and Health Professions at the Catholic University of the Sacred Heart (Rome Campus) during their first Health Surveillance visit, that took place from 2013 to 2023.

RESULTS

Our study sample included 2523 students, 44.4 % were protected against Hepatitis B, 87.3 % against measles, 85.5 % against mumps, 94.6 % rubella and 95.2 % against varicella. Differences in antibody coverage between age groups were statistically significant (p < 0.001), except for mumps. It found a lower probability of having seronegative anti-HBVs with an older date since the presumed primary vaccination.

CONCLUSION

In our sample, seropositivity rate against vaccine-preventable diseases, especially for Hepatitis B, was often inadequate to prevent possible biological risks connected with the activities carried out on the ward.

The potential effect of HBV vaccination on off-treatment HBsAg reversion after interferon-induced HBsAg clearance

Off-treatment HBsAg reversion occurs in a considerable number of chronic hepatitis B(CHB) patients after IFN(interferon)-induced HBsAg clearance. HBV vaccination protects the general population against HBV infection. However, it remains unclear whether HBV vaccination could prevent off-treatment HBsAg reversion in CHB patients with HBsAg clearance. CHB patients (n = 199) with HBsAg clearance were included in the current study, comprising spontaneous HBsAg clearance group (n = 51), NA (nucleoside/nucleotide analogues)-induced group (n = 36) and IFN-induced group (n = 112). Log-rank test was performed to compare the cumulative incidences of HBsAg reversion between groups. Cox regression model was used to identify the factors associated with off-treatment HBsAg reversion. The 5-year cumulative incidence of HBsAg reversion in IFN-induced group was significantly higher than that in NA-induced group or spontaneous group (27.6% vs. 3.3% vs. 8.1%, both p < .05). In IFN-induced group, 66.7% of CHB patients received HBV vaccination. The cumulative incidence of HBsAg reversion in individuals with strong responses to HBV vaccination (HBsAb level >100mIU/ml) was significantly lower than that in those with weak responses to HBV vaccination (HBsAb level ≤100mIU/ml) or without HBV vaccination in IFN-induced group (7.7% vs. 58.5% vs. 31.9%, both p < .05). Multivariate Cox regression analysis confirmed strong responses to HBV vaccination were independently associated with a lower cumulative incidence of HBsAg reversion after IFN-induced HBsAg clearance (HR = 0.246, 95%CI: 0.066-0.907, p = .035). HBV vaccination has potential to prevent off-treatment HBsAg reversion in CHB patients after IFN-induced HBsAg clearance via a sufficiently high level of HBsAb, helping clinicians optimize the clinical management of such patients.

Association between a low response to rubella vaccination and reduced anti-severe acute respiratory syndrome coronavirus 2 immune response after vaccination with BNT162b2: a cross-sectional study

OBJECTIVES

Some vaccinated individuals fail to acquire an adequate immune response against infection. We aimed to determine whether mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination could induce a sufficient immune response against SARS-CoV-2 in low responders to other vaccinations.

METHODS

Using data from health-care workers who received two doses of the BNT162b2 vaccine (BioNTech/Pfizer), we conducted a single-centre, cross-sectional study to determine whether low responders to measles, rubella, and hepatitis B virus (HBV) vaccinations could acquire sufficient antibodies after SARS-CoV-2 vaccination. From May 2021 to June 2021, participants were tested for anti-SARS-CoV-2 spike (anti-S) IgG antibodies at least 2 weeks after the second dose of BNT162b2. The association between a low response to measles, rubella, and HBV vaccinations and the post-vaccination anti-S IgG titre was evaluated using the multivariable linear regression analysis.

RESULTS

All 714 participants were positive for the anti-S IgG titre (≥50.0 AU/mL) after two doses of BNT162b2 (median, 7126.8 AU/mL; interquartile range, 4496.2-11 296.8). There were 323 (45.2%), 131 (18.3%), and 43 (6.0%) low responders to measles, rubella, and HBV vaccinations, respectively. In the multivariable linear regression analysis, low responders to rubella vaccination had significantly low acquisition of the anti-S IgG titre after two doses of the BNT162b2 vaccine (standardized coefficient β, -0.110; 95% CI, -0.175 to -0.044).

CONCLUSIONS

A low response to rubella vaccination is a potential predictor of a reduced response to SARS-CoV-2 vaccination. Further studies are needed to determine whether a low response to rubella vaccination is associated with the durability of SARS-CoV-2 vaccination-induced immune response.

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.

Prevalence and management of rubella susceptibility in healthcare workers in Italy: A systematic review and meta-analysis

Introduction

In the pre-vaccination era, all adults acquired immunity status due to natural infections during childhood and adolescence, whereas universal mass vaccination has changed the seroepidemiology of rubella among adults, showing lack of immunity in some subgroups. National and international guidelines recommend evaluating all healthcare workers (HCWs) for their immune status to rubella and possibly vaccinating those who are seronegative. We conducted a systematic review and meta-analysis to estimate the susceptibility rate to rubella among HCWs in Italy and to explore possible options for the management of those found to be susceptible.

Methods

Eight studies were included in the meta-analysis, selected from scientific papers available in the MEDLINE/PubMed and Google Scholar (till page 10) databases between January 1, 2015 and November 30, 2021. The following terms were used for the search strategy: (sero* OR seroprevalence OR prevalence OR susceptibilit* OR immunit* OR immunogenict*) AND (healthcare worker* OR health personnel OR physician* OR nurse OR student*) AND (rubella OR german measles OR TORCH) AND (Italy)

Results

The prevalence of rubella-susceptible HCWs was 9.0 % (95 %CI: 6.4–12.1 %). In a comparison of female vs. male serosusceptible HCWs, the RR was 0.67 (95 %CI = 0.51–0.88). Occupational medicine examinations for rubella screening with possible subsequent vaccination of seronegatives and exclusion of susceptible HCWs from high-risk settings were common management strategies.

Conclusions

HCWs susceptible to rubella are an important epidemiological concern in Italy, and efforts to identify and actively offer the vaccine to this population should be increased.

Evaluation of the effect of enhanced immunization in adults: A cross-sectional study in the southeast city of China

The efficacy of hepatitis B vaccination in adults was evaluated by comparison of the positive seroprotection rates and the hepatitis B surface antibody (anti-HBs) geometric mean titers (GMTs) between intensive intervention areas and non-intensive intervention areas after 8 years post-vaccination in the Zhejiang province. Seven cities (towns) in Zhejiang province were selected as intensive intervention areas, and adults in the demonstration areas receive hepatitis B vaccine voluntarily and for free. Other areas were non-intensive intervention areas. A total of 3587 participants received the full vaccination course (three doses), and blood samples were withdrawn 8 years after the first vaccination comprised the immunized group, and 2000 participants constituted the control group. The anti-HBs positive seroprotection rates of the immunized and control groups were 65.0% and 53.0%, respectively. The anti-HBs GMT of the subjects in the immunized group was 26.30 mIU/mL compared to 9.33 mIU/mL in the control group (P < .001). Significant differences were detected in the 24-35-, 36-45-, and 46-55-year-old subgroups in the positive seroprotection rates and the anti-HBs GMTs (P < .001) between the immunized and control groups. Moreover, significant differences were found in the anti-HBs GMT in the 46-55-year-old subgroup between the two groups (P = .02), while no differences were observed in the positive seroprotection rate (P = .428). In conclusion, adults who did not receive the hepatitis B vaccine in infancy and had negative serological markers of hepatitis B, especially adults <47-years-old, need vaccination.

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.

COVID-19 vaccination hesitancy in Italian healthcare workers: a systematic review and meta-analysis

INTRODUCTION

As for other vaccines, vaccination hesitancy may be a determining factor in the success (or otherwise) of the COVID-19 immunization campaign in healthcare workers (HCWs).

AREAS COVERED

To estimate the proportion of HCWs in Italy who expressed COVID-19 vaccine hesitancy, we conducted a systematic review of the relevant literature and a meta-analysis. Determinants of vaccine compliance and options suggested by these studies to address vaccine hesitancy among HCWs were also analyzed. Seventeen studies were included in the meta-analysis and systematic review, selected from scientific articles available in the MEDLINE/PubMed, Google Scholar and Scopus databases between January 1, 2020 and January 25, 2022. The vaccine hesitancy rate among HCWs was 13.1% (95%CI: 6.9-20.9%). The vaccine hesitancy rate among HCWs investigated before and during the vaccination campaign was 18.2% (95%CI=12.8-24.2%) and 8.9% (95%CI=3.4-16.6%), respectively. That main reasons for vaccine hesitation were lack of information about vaccination, opinion that the vaccine is unsafe, and fear of adverse events.

EXPERT OPINION

Despite strategies to achieve a greater willingness to immunize in this category, mandatory vaccination appears to be one of the most important measures that can guarantee the protection of HCWs and the patients they care for.

Sex and age as determinants of the seroprevalence of anti-measles IgG among European healthcare workers: A systematic review and meta-analysis

INTRODUCTION

The international literature shows good evidence of a significant rate of measles susceptibility among healthcare workers (HCWs). As such, they are an important public health issue.

METHODS

We conducted a systematic review and meta-analysis to estimate the prevalence of susceptible HCWs in EU/EEA countries and in the UK and to explore the characteristics (sex and age differences) and management of those found to be susceptible.

RESULTS

Nineteen studies were included in the meta-analysis. The prevalence of measles-susceptible HCWs was 13.3% (95 %CI: 10.0-17.0%). In a comparison of serosusceptible female vs. male HCWs, the RR was 0.92 (95 %CI = 0.83-1.03), and in a comparison of age classes (born after vs. before 1980) the RR was 2.78 (95 %CI = 2.20-3.50). The most recent studies proposed the mandatory vaccination of HCWs.

DISCUSSION

According to our meta-analysis, the prevalence of serosusceptible European HCWs is 13%; HCWs born in the post-vaccination era seem to be at higher risk. Healthcare professionals susceptible to measles are a serious epidemiological concern. Greater efforts should therefore be made to identify those who have yet to be vaccinated and actively encourage their vaccination.

Undetectable Anti-HBs Antibodies: Need of a Booster Dose for HIV-1-Infected Individuals

HBV vaccination effectively prevents HBV transmission and the development of liver cancer. Disease progression and liver-related complications are more common in HIV-1/HBV co-infected than HBV mono-infected individuals. A considerable body of literature, which will be reviewed here, indicates that response to HBV vaccine is suboptimal in HIV-1-infected individuals and that the poor maintenance of protective immunity to HBV vaccines in these individuals is an important medical issue. Several factors affect HBV vaccine response during HIV-1 infection including CD4+ T cell counts, B cell response, vaccine formulation, schedules, and timing of antiretroviral therapy (ART). The initial response to HBV vaccination also plays a critical role in the sustainability of antibody responses in both HIV-1-infected and uninfected vaccinees. Thus, regular follow-up for antibody titer and a booster dose is warranted to prevent HBV transmission in HIV-1 infected people.

Two years of on-site influenza vaccination strategy in an Italian university hospital: main results and lessons learned

Although the vaccination of healthcare workers (HCWs) is considered essential for preventing influenza circulation in the hospital setting, vaccination coverage (VC) in this group remains low. Among the reasons cited by HCWs is a lack of time to attend the vaccination clinic. For the 2018/2019 influenza season, active (on-site) influenza vaccination was offered directly in 44 operative units (OUs) of the Bari Policlinico hospital (50 OUs, 3,397 HCWs). At the same time, the hospital granted the HCW access to the vaccination clinic during October and December 2018. VC achieved among HCWs of Bari Policlinico during the 2018/2019 influenza season was then analyzed, and the results compared with those of the 2017/18 season. During the 2018/19 season, VC was 20.4% (n = 798) and thus higher than the 14.2% of the 2017/18 season (+6.2%). The highest VC was among physicians (33.4%), followed by other HCWs (23.8%), auxiliary staff (8.6%), and nurses (7.2%). Overall, 284 (36.5%) HCWs were vaccinated at on-site sessions. Multivariate analysis showed that vaccination uptake was associated with male gender and with work in OU where vaccination was actively offered. On the other hand, being a nurse or auxiliary staff member and working in the surgical area were deterrents. Although VC remained unsatisfactory, active on-site vaccination proved to be an important strategy to improve vaccination compliance, increasing 44% compared to the previous season. Nonetheless, mandatory vaccination directed by public health institutions may be the only way to reach a minimum level of coverage.

Pregnant women's hepatitis B vaccination coverage in Nigeria: a national pilot cross-sectional study

OBJECTIVE

To determine the hepatitis B vaccination coverage, full-dose (⩾3) coverage and the associated factors affecting uptake among pregnant women.

METHODS

This was a cross-sectional study among pregnant women attending antenatal care in six tertiary hospitals across all the geopolitical zones of Nigeria. Pregnant women who consented to the study completed screening questions about their hepatitis B vaccination status and coverage. The main outcome measures were hepatitis B vaccination coverage rate, dose, and factors affecting uptake. Bivariate analysis was performed by the chi-square test and conditional logistic regression analysis was used to determine variables associated with uptake of the vaccination. Odds ratios (ORs) and adjusted odds ratios (aORs) were calculated and statistical significance was accepted when p-value was < 0.05.

RESULTS

Of 159 pregnant women who completed the interview questions, 21 [13.2%, 95% confidence interval (CI) 7.9-18.5%] were vaccinated for hepatitis B for one to three doses. The numbers of doses received were: three doses (8/159, 5.0%), two doses (5/159, 3.1%), and one dose (8/159, 5.0%). The reasons for non-uptake of vaccination included: lack of awareness of the vaccine 83/138 (60.1%), inadequate access to vaccine 11/138 (8.0%), and positivity to hepatitis B virus 10/138 (7.2%). The uptake of hepatitis B vaccination was significantly affected by the level of education (OR 0.284, 95% CI 0.08-1.01, p = 0.041), but in multivariable logistic regression, adjusted for confounders, the association between hepatitis B vaccination and participants' level of education (aOR 3.09; 95% CI 0.95-10.16; p = 0.061) did not remain significant.

CONCLUSIONS

In Nigeria, the national hepatitis B vaccination coverage among pregnant women appears poor, with the full-dose coverage even poorer. The level of education was not positively associated with uptake of hepatitis B vaccination, while lack of awareness of the vaccine was the commonest reason for non-uptake.

FUNDING

TETFund National Research Fund 2019 (grant number TETFund/DR&D/CE/NRF/STI/33).

Long-term immunogenicity after measles vaccine vs. wild infection: an Italian retrospective cohort study

The persistence of specific IgG after measles infection and after measles vaccination has not been sufficiently investigated. Current evidence suggests that immunity after the disease is life-long, whereas the response after two doses of measles-containing vaccine declines within 10-15 years. This study evaluated the proportion of individuals with detectable anti-measles IgG in two groups, those vaccinated with two doses of anti-MMR vaccine and those with a self-reported history of measles infection. Among the 611 students and residents who were tested, 94 (15%) had no detectable protective anti-measles IgG. This proportion was higher among vaccinated individuals (20%; GMT = 92.2) than among those with a self-reported history of measles (6%; GMT = 213.3; p < .0001). After one or two MMR vaccine booster doses, the overall seroconversion rate was 92%. An important proportion of people immunized for measles did not have a protective IgG titer in the years after vaccination, but among those who had a natural infection the rate was three-fold lower. This finding should be considered in the pre-elimination phase, given the resurgence of measles cases among individuals who after being vaccinated lost their circulating IgG after several years, especially if they failed to receive a natural booster.

Long -term persistence of antibodies against varicella in fully immunized healthcare workers: an Italian retrospective cohort study

Background

Chickenpox is a highly contagious disease caused by the varicella zoster virus (VZV), and in infants, adolescents, adults, pregnant women, and the immunocompromised it can be serious. The best way to prevent chickenpox is immunization with the varicella vaccine. Protective levels of antibodies induced by the varicella vaccine decline over time, but there is currently no formal recommendation for testing anti-varicella zoster virus (VZV) IgG levels in immunized healthcare workers (HCWs).

Methods

The aims of this study were to evaluate the seroprevalence of circulating anti-VZV IgG in a sample a sample of students and residents of the medical school of the University of Bari, the long-term immunogenicity of the varicella vaccine, and the effectiveness of a strategy consisting of a third vaccine booster dose. The study population was screened as part of a biological risk assessment conducted between April 2014 and October 2020. A strategy for the management of non-responders was also examined.

Results

The 182 students and residents included in the study had a documented history of immunization (two doses of varicella vaccine). The absence of anti-VZV IgG was determined in 34% (62/182; 95%CI = 27.2–41.4%), with serosusceptibility more common among males than females (p < 0.05). After a third varicella dose, seroconversion was achieved in 100% of this previously seronegative group. No serious adverse events were recorded.

Conclusions

One-third of the study population immunized against VZV lacked a protective antibody titer, but a third dose of vaccine restored protection. Since it is highly unlikely that VZV will be eliminated in the immediate future, the loss of immunity in a substantial portion of the population implies a risk of varicella outbreaks in the coming years. Screening for varicella immunity in routine assessments of the biological risk of medical students and HCWs may help to prevent nosocomial VZV infections.

Role and Tasks of the Occupational Physician during the COVID-19 Pandemic

Background and Objectives: The first clusters of SARS-CoV-2 infection were identified in an occupational setting, and to date, a significant portion of the cases may result from occupational exposure; thus, COVID-19 should also be considered a new occupational risk that both directly and indirectly impacts the health of workers. Given the significance of occupational-exposure-related infections and deaths, this study aims to assess the roles and tasks of occupational physicians (OPs) in countering the spread of the infection. Indeed, despite the OP's centrality in risk management in the workplace, its activity in the current epidemic context has rarely been mentioned. Materials and Methods: Three different databases (PubMed, Google Scholar, and Embase) were questioned using the main keywords "COVID-19" and "SARS-CoV-2" that were crossed, according to different needs, with the terms "occupational medicine", "occupational physician", "workplace", and "risk assessment" using, when possible, the MeSH database research. Additionally, a systematic research of the regulatory changes of workplaces health surveillance was performed on reference sites of international, European, and Italian authorities. Results: Fundamental tasks and duties of OPs in the current COVID-19 outbreak are highlighted by examining their clinical activity and technical action. A risk assessment and management workflow is proposed, and medico-legal implications in case of infection at work are also discussed in the light of recent regulatory changes that clearly attribute to OPs an important role in safeguarding public health. Conclusion: The proposed approach can provide new instruments to contrast the spread of the infection as part of a comprehensive system response to the current pandemic, for which OPs are called to assume full responsibility.

Long-term persistence of poliovirus neutralizing antibodies in the era of polio elimination: An Italian retrospective cohort study

INTRODUCTION

The extensive use of oral and inactivated poliovirus (PV) vaccines has driven progress toward the global eradication of wild PV2 and PV3 and the elimination of PV1 in most countries, including Italy. Although the persistence of circulating neutralizing antibodies among the vaccinated is unclear, it is estimated that > 99% of the population vaccinated according to the recommended protocol should be protected for at least 18 years.

METHODS

This study evaluated the seroprevalence of anti-PV neutralizing antibodies and the long-term immunogenicity of the oral poliovirus vaccine (OPV) in a sample of medical students and residents of the University of Bari who attended the Hygiene Department for a biological risk assessment between April 2014 and October 2020.

RESULTS

The prevalence of protected vaccinated individuals was > 90% for PV1, PV2, and PV3. Specifically, >99% of the study group was protected against PV1, > 98% against PV2, and almost 93% against PV3. Protective antibodies against all three viruses persisted for at least up to 18 years after administration of the last OPV dose, with PV1 and PV2 antibodies detected in > 95% of the participants > 30 years after the last OPV dose.

CONCLUSIONS

The childhood series of four doses of OPV guarantees a long duration of protection, despite the elimination of the virus and therefore the absence of a natural booster. However, until PV1 is completely eradicated, maximum vigilance on the part of public health institutions must be maintained.

Hepatitis B-C and human immunodeficiency virus: seroprevalence and associated factors among health students in Saudi Arabia

OBJECTIVES

To assess the seroprevalence of Hepatitis B (HBV), Hepatitis C (HCV), and Human Immunodeficiency Virus (HIV) among newly admitted health track students in a large university in the Eastern Province of Saudi Arabia, and determine the students' immunity against HBV, and bloodborne viral infection risk factors or practices among them.

METHODS

Information about the 1145 students, vaccination history, and exposure to bloodborne viral infections risk factors/practices were collected using a structured questionnaire during August 2020. The results of serological data were obtained from students' electronic files.

RESULTS

All students tested negative for HBV, HCV, and HIV infections. The seroprevalence of positivity against HBV was 25.8%, and the frequencies of students with protective levels of anti-HBV were inversely related to their age. The majority (70.8%) of students had 1 or 2 identifiable risk factors for bloodborne diseases, and the most frequent risk factor was history of dental intervention. Female students were more than four-times likely to be in the high-risk group for bloodborne infections than males (OR = 4.4; 95% CI: 3.3-5.9). Being from the Central Province of Saudi Arabia (OR = 1.9; 95% CI: 1.2-3.1) and having a mother's educational level of master or doctorate (OR = 3.0; 95% CI: 1.3-6.7) were found to be independent predictors of being in the high-risk group. On the other hand, having a family member in the healthcare field was found as a predictor of being in the low-risk group for bloodborne diseases (OR = 0.7; 95% CI: 0.5-0.9).

CONCLUSION

About three-fourth of students in this study were susceptible to HBV. Our findings stress the need to develop policies to raise awareness regarding bloodborne infectious diseases, in addition to expanding access to HBV vaccination for healthcare staff, especially in older ages.

Seroprevalence for vaccine-preventable diseases among Italian healthcare workers

Healthcare workers (HCWs) have an increased risk to be exposed to infectious diseases compared to the general population. For this reason, according to the National Immunization and Prevention Plan, all HCWs should have demonstrable evidence of immunity to measles, mumps, rubella, varicella and Hepatitis B. Earlier studies have already shown that a large percentage of Italian operators lacked immune protection for one or more of those pathogens.The aim of this study was to evaluate the immunization status for vaccine-preventable diseases of HCWs in a large Italian teaching hospital. We retrospectively evaluated clinical records and serological data of HCWs who followed the occupational health surveillance program between January 1 and December 31 2019. We reviewed the clinical records of 1,017 HCWs: 393 males and 624 females with a median age of 35.69 y (range: 19-67). Protective IgG antibody values were documented in the 88.0%, 75.7%, 90.3%, 87.4% and 85.7% of the HCWs screened, respectively, against measles, mumps, rubella, varicella and Hepatitis B. Age was significantly related to serological protection against measles, mumps and varicella but was not significantly related to protective IgG levels for rubella and HBV.Female gender was significantly related to a higher protection rate against Hepatitis B (87.8 vs 82.4%; p < .01) whereas males were significantly more protected against varicella (92-4 vs 84.1%; p < .01).Our study shows suboptimal levels of protection among Italian HCWs and a consequent increased risk of infection for them and their patients. Public health policies should be focused on improving preventive strategies, including serological screening and workplace vaccination of nonimmune individuals.

Kinetics of Anti-Hepatitis B Surface Antigen Titers in Nurse Students after a Two-Year Follow-Up

Infection caused by hepatitis B virus (HBV) can be prevented through a safe and effective vaccine. This study analysed the kinetics of serum antibodies against hepatitis B surface antigen (HBsAg) (anti-HBs) titers in relation to previous vaccine boosters in Italian nursing students who were followed up for two years. Serum anti-HBs titers were evaluated at the first visit, after vaccine booster (if required) and at visit after two years. Overall, 483 students (mean age = 21.7 years; SD = 3.7) with median anti-HBs IgG titer of 6 mUI/mL (interquartile range (IQR) = 0-34) were enrolled. A total of 254 (52.5%) students with a titer lower than 10 mIU/mL were offered an anti-HBV booster at the first visit. Among these students, an exponential relation between anti-HBs IgG titer, one month after HBV booster and anti-HBs IgG titer two years later was found (y = 3.32 exp (0.0045x); R2 = 0.48; p < 0.001). Students with anti-HBV titer higher than 10 mIU/mL (N = 229) were followed up, and anti-HBs IgG titers at follow-up visit linearly correlated with anti-HBV baseline titers (y = 0.86x + 26.2; R2 = 0.67; p < 0.001). A decrease in anti-HBs titers can be expected a few years after the anti-HBV booster dose. This reduction is more pronounced than that observed in students not administered the booster dose and is exponential with respect to basal titers assessed after the booster dose.

Is There Any Opportunity to Provide an HBV Vaccine Booster Dose Before Anti-Hbs Titer Vanishes?

Whether the primary Hepatitis B vaccination confers lifelong protection is debated. The aim of the study was to assess the effectiveness of booster doses in mounting a protective HBV immune response in subjects vaccinated 18-20 years earlier. The study population consisted of vaccinated students attending medical and healthcare professions schools. A booster dose was offered to subjects with a <10 mIU/mL anti-HBs titer. The post-booster anti-HBs titer was evaluated after four weeks. The subjects with a <10 mIU/mL post-booster anti-HBs titer, received a second and third dose of the vaccine and after one month they were retested. A <10 mIU/mL anti-HBs titer was found in 35.1% of the participants and 92.2% of subjects that were boosted had a ≥10 mIU/mL post-booster anti-HBs titer, whereas 7.8% did not mount an anamnestic response. A low post-booster response (10-100 mIU/mL anti-HBs) was significantly more likely in subjects with a <2.00 mIU/mL pre-booster titer compared to those with a 2.00-9.99 mIU/mL pre-booster titer. The anamnestic response was significantly related to the baseline anti-HBs levels. A booster dose of the HBV vaccine may be insufficient to induce an immunological response in subjects with undetectable anti-HBs titers. A booster dose might be implemented when an anamnestic response is still present.

Compliance with immunization and a biological risk assessment of health care workers as part of an occupational health surveillance program: The experience of a university hospital in southern Italy

BACKGROUND

The active immunization of health care workers (HCWs) is a primary measure to prevent nosocomial infection; despite this, vaccine coverage among HCWs in most countries is low. To increase vaccine coverage in the health care setting, the hygiene and occupational medicine departments of Bari Policlinico General University-Hospital implemented a vaccination procedure. This operative procedure requires that during the occupational medical examination, all employees are evaluated for immunity/susceptibility to vaccine-preventable diseases, with vaccination offered to those determined to be susceptible.

METHODS

The study sample comprised HCWs who attended the biological risk assessment program from December 2017 to January 2019 (n = 449).

RESULTS

Susceptibility was higher for hepatitis B virus (23%), followed by rubella (11%), varicella (9%), mumps (8%), and measles (7%). The seroconversion rate after the administration of booster dose(s) was >80% for all vaccines. Overall, 15% of the HCWs refused the offered vaccine(s), and the main determinants of vaccination compliance were younger age (P < .0001) and being a physician (P < .05).

DISCUSSION

Despite the several recommendations and campaigns to promote vaccinations, achieving high immunization rates among HCWs is still a challenge.

CONCLUSIONS

In this scenario, public health institutions have to choose between the enforcement of the promotion or the adoption of a mandatory policy.

Long time persistence of antibodies against Mumps in fully MMR immunized young adults: an Italian retrospective cohort study

Protective levels of antibodies induced by the MMR vaccine have been shown to decline over time, but actually there is not a formal recommendation about the opportunity of testing immunized HCWs to investigate the persistence of anti-Mumps IgG. This study aims to evaluate the long-time immunogenicity of MMR vaccination in a sample of medical students and residents of the University of Bari who attended the Hygiene Department for the biological risk assessment (April 2014-June 2018). A strategy for the management of non-responder subjects has been experimented and described. Two thousand students and residents, with documented immunization status (two doses of MMR vaccine), have been tested. 120/2,000 (6%; 95%CI = 5.0–7.1%) subjects did not show anti-Mumps IgG. This percentage was similar among males and females. After a third MMR dose, we noted a seroconversion of 90% of seronegative participants. No serious adverse events were recorded. An important proportion of subjects immunized for MMR do not show an antibodies protective titer. The immunogenicity and the safety of the third dose seem confirmed by our data. Including the screening model described in the routine assessment of the biological risk of medical students and HCWs may be a winning strategy in preventing Mumps nosocomial infection.

Discordance of hepatitis B vaccination policies for healthcare workers between the USA, the UK, and Germany

The hepatitis B (HB) vaccine is effective for the prevention of HB virus infection. It has been widely accepted that an anti-HB surface antibody (HBs) level ≥10 mIU/mL is protective against HB virus infection. Although transient infection can occur in individuals who attain a peak level of anti-HBs ≥10 mIU/mL after primary vaccination, long-term follow-up studies show that successful primary vaccination can prevent individuals from acute clinical hepatitis and chronic infection. Healthcare workers (HCWs) are at-risk individuals. Based on the accumulated data, the USA considers an anti-HBs level ≥10 mIU/mL to constitute successful vaccination for HCWs. In contrast, because some anti-HBs assays cannot accurately measure in the low anti-HBs range, including 10 mIU/mL, the UK and Germany consider an anti-HBs level ≥100 mIU/mL to constitute successful vaccination for HCWs. In the USA and UK, a booster dose is unnecessary for HCWs after successful vaccination. In Germany, anti-HBs testing is recommended for HCWs who are at particularly high individual exposure risk 10 years after successful primary immunization, and a booster dose is offered if the anti-HBs level has declined to ˂100 mIU/mL. The differences in the goal of HB vaccination, reliability of anti-HBs assays, and use of booster vaccination cause discordance in HB vaccination policies for HCWs.

Long-term Immunogenicity of Measles Vaccine: An Italian Retrospective Cohort Study

BACKGROUND

Levels of antibodies induced by the measles virus-containing vaccine have been shown to decline over time, but there is no formal recommendation about testing immunized subjects (in particular, healthcare workers [HCWs]) to investigate the persistence of measles immunoglobulin G (IgG).

METHODS

This study aims to evaluate the long-term immunogenicity of measles vaccine in a sample of medical students and residents of the University of Bari who attended the Hygiene Department for a biological risk assessment (April 2014-June 2018).

RESULTS

Two thousand immunized (2 doses of measles-mumps-rubella [MMR] vaccine) students and residents were tested; 305 of these (15%) did not show protective anti-measles IgG. This proportion was higher among subjects who received vaccination at ≤15 months (20%) than in those who received vaccination at 16-23 months (17%) and at ≥24 months (10%) (P < .0001). After an MMR vaccine booster dose, we noted a seroconversion of 74% of seronegative HCWs. The overall seroconversion rate after a second dose (booster) was 93%. No serious adverse events were noted after the booster doses.

CONCLUSIONS

An important proportion of subjects immunized for measles do not show a protective IgG titer in the 10 years after vaccination. Our management strategy seems consistent with the purpose of evidencing immunological memory.

Hepatitis B surface antibodies seroprevalence among people born before and after implementation of universal HBV vaccination

Universal vaccination is the most effective strategy to control hepatitis B virus (HBV) infection. In Argentina, vaccination against HBV was incorporated in year 2000 for newborns and in 2003 for 11 years old children. However, there is a paucity of data about protection levels against HBV infection. The aim of this work was to determine the prevalence of seroprotective anti-HBs antibodies (aHBs) in Argentina. Serum samples negative for HBsAg and anti-HBc from 132 children born after year 2000 and 762 blood donors, older than 18 years, from five centers across the country, were analyzed for aHBs. Titers ≥10 mIU/mL were observed in 74/132 children (56.1%) and 336/762 (44.1%) in blood donors. The median age for blood donors was 33.9 (23-43); from them, 210 (27.6%) were born after 1992 and, therefore, were catch-up by vaccine implementation at 11 years old age. Donors born in 1992 or before showed a significantly lower frequency of protection (32.2%) compared to donors born after 1992 (75.2%), p < 0.0001. In addition, significant differences were observed in the status of seroprotection between different participating centers (p = 0.024). Implementation of HBV vaccine in 2000 and 2003 implied an overall increase of the aHBs seroprotective rates, with a particularly adequate response in children vaccinated at 11 years old age. The observed results suggest that population born in 1992 or before is currently the most susceptible. Consequently, it would be advisable to become aware of the risk of transmission in this age group and to stress this population vaccination campaigns.

Immunity to rubella: an Italian retrospective cohort study

Background

International guidelines recommend that healthcare workers (HCWs) have presumptive evidence of immunity to rubella and that susceptible HCWs and doubt cases receive two doses of the MMR vaccine. However, a small percentage of the fully immunized will remain unprotected against wild viruses. Moreover, protective levels of antibodies induced by the vaccine have been shown to decline over time, but a formal recommendation regarding the testing of immunized HCWs for the persistence of IgG against rubella is lacking.

Methods

The aim of this study was to evaluate the long-term immunogenicity conferred by rubella vaccination and the effectiveness of a strategy for the management of immunized individuals in whom IgG against rubella could not be demonstrated (non-responders). The study enrolled students and medical residents who attended the Hygiene Department of Bari Policlinico University Hospital for biological risk assessment (April 2014 to June 2018).

Results

Two thousand students and residents with documented immunization (≥2 doses of rubella or MMR vaccine) were tested. In 181 (9%), IgG against rubella was not detectable. The seronegative rate was higher among participants vaccinated at age < 2 years (89.6%) and lower among those immunized at age ≥ 2 years (93.6%; p < 0.0001). The administration of a single MMR booster dose resulted in a seroconversion rate of 98% in the seronegative group. The seroconversion rate after a second booster dose was 100%. No serious adverse events in the re-immunized were recorded.

Conclusions

An important proportion of individuals immunized for rubella or MMR do not have a protective titer for the disease(s). Our management strategy (booster followed by re-test and, for those who are still negative, a second booster and re-test) is consistent with the goal of achieving immunological memory.

Implementation strategy and cost of Mozambique's HPV vaccine demonstration project

BACKGROUND

Cost is an important determinant of health program implementation. In this study, we conducted a comprehensive evaluation of the implementation strategy of Mozambique's school-based HPV vaccine demonstration project. We sought to estimate the total costs for the program, cost per fully immunized girl (FIG), and compute projections for the total cost of implementing a similar national level vaccination program.

METHODS

We collected primary data through document review, participatory observation, and key informant interviews at all levels of the national health system and Ministry of Education. We used a combination of micro-costing methods-identification and measurement of resource quantities and valuation by application of unit costs, and gross costing-for consideration of resource bundles as they apply to the number of vaccinated girls. We extrapolated the cost per FIG to the HPV-vaccine-eligible population of Mozambique, to demonstrate the projected total annual cost for two scenarios of a similarly executed HPV vaccine program.

RESULTS

The total cost of the Mozambique HPV vaccine demonstration project was $523,602. The mean cost per FIG was $72 (Credibility Intervals (CI): $62 - $83) in year one, $38 (CI: $37 - $40) in year two, and $54 CI: $49 - $61) for years one and two. The mean cost per FIG with the third HPV vaccine dose excluded from consideration was $60 (CI: $50 - $72) in year one, $38 (CI: $31 - $46) in year two, and $48 (CI: $42 - $55) for years one and two. The mean cost per FIG when only one HPV vaccine dose is considered was $30 (CI: $27 - $33)) in year one, $19 (CI: $15-$23) in year two, and $24 (CI: $22-$27) for both years. The projected annual cost of a two-and one-dose vaccine program targeting all 10-year-old girls in the country was $18.2 m (CI: $15.9 m - $20.7 m) and $9 m (CI: $8 m - $10 m) respectively.

CONCLUSION

National adaptation and scale-up of Mozambique's school-based HPV vaccine strategy may result in substantial costs depending on dosing. For sustainability, stakeholders will need to negotiate vaccine price and achieve higher efficiency in startup activities and demand creation.