Long-term persistency of hepatitis B immunity: an observational cross-sectional study on medical students and resident doctors

Immune Status for Hepatitis B and Risk for Occupational Exposure Virus Among Italian Nurses

Background: Healthcare workers (HCWs) are considered at higher risk for hepatitis B virus infection compared to the general population, due to their potential contact with blood or body fluids and possible needle stick injuries. In turn, infected HCWs may be a risk for patients. Hepatitis B vaccination programs represent a strategic approach to control the infection. Objectives: In this study, we aimed to evaluate the serological status of HCWs employed at the teaching hospital of Rome Tor Vergata and their risk of occupational injuries after the adoption of directive 2010/32/EU. Methods: Medical records of 539 HCWs were evaluated during their occupational medical examination at the Tor Vergata teaching hospital (PTV). All subjects were screened for specific viral markers: Hepatitis B surface antibodies (anti-HBs IgG), antibodies to hepatitis core antigen (anti-HBc IgG), and hepatitis B surface antigen (HBsAg). Data regarding needlestick injuries were collected by the prevention service team during the same year. Results: In this sample population, we found five subjects (0.9%) positive to the HBsAg, and most of them (four) were born in foreign countries. Moreover, seven subjects (1.3% of our population) were HBsAg-positive and anti-HBc-positive. A protective anti-HBs titer was found in 462 out of 527 (85.7%) subjects. The risk of being serologically unprotected was higher in males and subjects aged 40 years or older. The nurses were more protected than other healthcare professionals considering the anti-hepatitis B surface antibody titer. In 2018, 16 needlestick injuries were reported among our population of HCWs, with a global risk of 2.9% per year. Conclusions: Although hepatitis B virus (HBV) infection rate among HCWs was similar to that of the general population, the risk of HBV transmission in HCWs was likely to be high due to suboptimal vaccination coverage.

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.

Insights into induction of the immune response by the hepatitis B vaccine

After more than four decades of hepatitis B virus (HBV) vaccine implementation, its safety and efficacy in preventing HBV infection have been proven and several milestones have been achieved. Most countries have included HBV immunization schedules in their health policies and progress has been made regarding universalization of the first HBV vaccine dose at birth. All of these actions have significantly contributed to reducing both the incidence of HBV infection and its related complications. However, there are still many drawbacks to overcome. The main concerns are the deficient coverage rate of the dose at birth and the large adult population that has not been reached timely by universal immunization. Additionally, the current most widely used second-generation vaccines do not induce protective immunity in 5% to 10% of the population, particularly in people over 40-years-old, obese (body mass index > 25 kg/m²), heavy smokers, and patients undergoing dialysis or infection with human immunodeficiency virus. Recently developed and approved novel vaccine formulations using more potent adjuvants or multiple antigens have shown better performance, particularly in difficult settings. These advances re-launch the expectations of achieving the World Health Organization’s objective of completing hepatitis control by 2030.

The role of hepatitis B vaccine challenge dose in patients with underlying health conditions

We have evaluated the immunological response to Hepatitis B virus (HBV) booster vaccine dose in 129 adults with underlying diseases in comparison with 694 subjects at occupational risk of infection, who have previously completed the primary series and resulted with anti-HBs <10 mIU/mL. After booster dose, 60.5% of the patients with underlying diseases and 14.8% of the subjects at occupational risk resulted seronegative. By comparing two groups, rate of subjects with anamnestic response was higher in at occupational risk group respect to that at risk for medical conditions (OR: 5.99 [95%IC, 3.81-9.41], p < .001). This difference was associated to gender (males/females: OR: 0.619 [95%IC, 0.421-0.910], p = .015) and age (better response for younger people, p = .011).

Inadequate Vaccine Responses in Children With Multiple Sclerosis

Objective: Immunizations against Hepatitis B virus (HBV) and Varicella Zoster virus (VZV), are recommended for patients with pediatric onset multiple sclerosis (POMS) and may be required prior to initiation of some disease modifying therapies. However, the efficacy of routine vaccine administration in POMS has never been studied. We sought to assess the humoral mediated vaccine response to HBV and VZV in children with POMS. Methods: A multi-center retrospective chart-based review of 62 patients with POMS was performed. Clinical data and antibody titers against HBV and VZV were collected prior to initiation of disease modifying therapy or steroids and compared to institutional control data, using t-test and chi squared analysis. Results: There were low rates of immunity against both HBV and VZV (33 and 25% respectively) among individuals with POMS. Fifteen individuals (24%) were non-immune to both. Compared to institutional control data, individuals with POMS were significantly less likely to be immune to and HBV (p = 0.003, 95% CI: 0.22-0.75) and VZV (p < 0.001, 95% CI: 0.09-0.39). Interpretation: Individuals with POMS have low rates of antibody-mediated immunity against HBV and VZV, despite receiving the appropriate vaccinations. This suggests an association between POMS and systemic immune dysregulation although further study is needed.

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.

A Universal Plug-and-Display Vaccine Carrier Based on HBsAg VLP to Maximize Effective Antibody Response

Development of effective malaria vaccines requires delivery platforms to enhance the immunogenicity and efficacy of the target antigens. This is particularly challenging for transmission-blocking malaria vaccines (TBVs), and specifically for those based on the Pfs25 antigen, that need to elicit very high antibody titers to stop the parasite development in the mosquito host and its transmission. Presenting antigens to the immune system on virus-like particles (VLPs) is an efficient way to improve the quantity and quality of the immune response generated. Here we introduce for the first time a new VLP vaccine platform, based on the well-established hepatitis B surface antigen (HBsAg) fused to the SpyCatcher protein, so that the antigen of interest, linked to the SpyTag peptide, can be easily displayed on it (Plug-and-Display technology). As little as 10% of the SpyCatcher::HBsAg VLPs decorated with Pfs25::SpyTag (molar ratio) induces a higher antibody response and transmission-reducing activity in mice compared to the soluble protein, with 50 and 90% of the VLP coupled to the antigen further enhancing the response. Importantly, using this carrier that is a vaccine antigen itself could be beneficial, as we show that anti-HBsAg IgG antibodies are induced without interfering with the Pfs25-specific immune response generated. Furthermore, pre-existing anti-HBsAg immunity does not affect the antigen-specific response to Pfs25::SpyTag-SpyCatcher::HBsAg, suggesting that these VLPs can have a broad use as a vaccine platform.