Cost-effectiveness of hepatitis B vaccination using HEPLISAV™ in selected adult populations compared to Engerix-B® vaccine

Preventing Hepatitis B Virus Infection Among U.S. Military Personnel: Potential Impact of a 2-Dose Versus 3-Dose Vaccine on Medical Readiness

INTRODUCTION

Hepatitis B, a major public health issue worldwide, has been associated with serious clinical outcomes. Military personnel are at particular risk for hepatitis B, such that hepatitis B vaccination is part of the accession process for new recruits. Although lost time costs and medical cost avoidance have been used by the U.S. Military to guide their decision-making protocols, this has not been applied to hepatitis B vaccination costs. Herein, a decision-analytic model is used to compare the effective vaccine protection rates and vaccine and operational costs of 2-dose versus 3-dose hepatitis B vaccine regimens in a population of recruits from the U.S. Marine Corps Recruit Depot, Parris Island.

METHODS

A decision-analytic model was developed to assess the expected levels of adherence, seroprotection, and vaccination and operational costs of a cohort of recruits vaccinated with either a 2-dose (HepB-CpG) vaccine for those eligible (scenario 1) or a 3-dose (HepB-Alum) vaccine (scenario 2). De-identified data from 23,004 recruits at the Marine Corps Recruit Depot, Parris Island, in 2018 and 2019 were used to provide real-world data on age distribution and vaccination status. Other inputs included published data on adherence for hepatitis B vaccines and seroprotection rates for HepB-CpG and HepB-Alum in relation to the number of doses received. Costs included direct medical costs of the hepatitis B vaccination and operational costs such as missed training time.

RESULTS

After receipt of two vaccine doses, 92% of recruits in scenario 1 (HepB-CpG group) were expected to be protected against hepatitis B within 1 month of receiving the second dose, compared with 24% of recruits in scenario 2 (HepB-Alum group), leaving 76% of Marine recruits unprotected if using HepB-Alum during the intervening 5-month period between doses 2 and 3. Over the study period, HepB-CpG was estimated to provide cost savings of $744,509 (17.3% cost reduction) compared with HepB-Alum, with the cost of missed training time being the most influential driver of the cost difference between the two vaccination schedules.

CONCLUSIONS

Findings from this model suggest that vaccination with the 2-dose HepB-CpG vaccine may provide earlier and higher protection against hepatitis B compared with the 3-dose vaccine (HepB-Alum). A 2-dose vaccination strategy incorporated as part of individual medical readiness has the potential to not only increase protection but also confer economic savings among military recruits at risk for hepatitis B infection.

Cost-effectiveness of a 3-antigen versus single-antigen vaccine for the prevention of hepatitis B in adults in the United States

OBJECTIVES

The first 3-antigen hepatitis B vaccine was approved by the United States (US) Food and Drug Administration in November 2021 and was recommended by the Centers for Disease Control and Prevention in 2022. We estimated the cost-effectiveness of this 3-antigen vaccine (PreHevbrio™) relative to the single-antigen vaccine, Engerix-B^TM, to prevent hepatitis B virus (HBV) infection among US adults.

METHODS

A cost-effectiveness model was developed using a combined decision-tree and Markov structure to follow 100,000 adults over their remaining lifetimes after vaccination with either the 3-antigen or single-antigen vaccine. Outcomes from societal and healthcare sector perspectives were calculated for adults aged 18-44, 45-64, and ≥65 years; adults with diabetes; and adults with obesity. Seroprotection rates were obtained from the phase3, head-to-head PROTECT trial (NCT03393754). Incidence, vaccine costs, vaccine adherence rates, direct and indirect costs, utilities, transition probabilities, and mortality were obtained from published sources. Health outcomes and costs (2020USD) were discounted 3% annually and reported by vaccine and population. One-way sensitivity and scenario analyses were conducted.

RESULTS

In the model, the 3-antigen vaccine led to fewer HBV infections, complications, and deaths compared with the single-antigen vaccine in all modeled populations due to higher rates and faster onset of seroprotection. Compared with the single-antigen vaccine, the 3-antigen vaccine had better health outcomes, more quality-adjusted life-years (QALYs), and lower costs in adults aged 18-64 years, adults with diabetes, and adults with obesity (dominant strategy). For adults aged ≥65 years, the 3-antigen vaccine was cost-effective compared with the single-antigen vaccine ($26,237/QALY gained) below common willingness-to-pay thresholds ($50,000-$100,000/QALY gained). In sensitivity analyses, results were sensitive to vaccine cost per dose, incidence, and age at vaccination.

CONCLUSION

The recently approved 3-antigen vaccine is a cost-saving or cost-effective intervention for preventing HBV infection and addressing the long-standing burden of hepatitis B among US adults.

Efficacy of Hepatitis B Vaccination with a Novel Immunostimulatory Sequence Adjuvant (Heplisav-B) in Patients With Inflammatory Bowel Disease

BACKGROUND

Owing to the use of immunosuppressive agents, patients with inflammatory bowel disease (IBD) have an increased risk of vaccine preventable diseases, including infection with hepatitis B virus (HBV). Heplisav-B, an FDA-approved vaccine, is more effective (90% to 100%) than Engerix-B (70.5% to 90.2%) at inducing immunity to HBV in clinical studies. Available data on efficacy of Heplisav-B vaccine in patients with IBD are limited.

METHODS

This retrospective observational study included patients age 18 years and older with ulcerative colitis (UC) or Crohn's disease (CD) who received 1 or 2 doses of Heplisav-B vaccine and had postvaccination serologic testing. Prior to immunization, all participants were seronegative for HBsAb antibodies (HBsAb) measured as <10 IU/mL. Postvaccination HBsAb of ≥10 IU/mL was considered successful vaccination. Patient demographics, disease characteristics, and medications were abstracted.

RESULTS

One hundred six patients were included in the analysis. Median age was 43 years, and 44 (42%) were female. Thirty-nine patients (37%) had UC, whereas 67 (63%) had CD. Eighty-three patients (78.3%) had active immunity after vaccination with Heplisav-B, with median postvaccination HBsAb levels of 114 IU/L. Patients with chronic obstructive pulmonary disease, chronic kidney disease, diabetes mellitus, immunomodulator use, or those on 2 or more of immunosuppressive medications were less likely to respond to Heplisav-B, though these findings were not statistically significant on a multivariate analysis aside from chronic kidney disease.

CONCLUSIONS

Heplisav-B, a 2-dose vaccine, is an effective vaccine for HBV in patients with IBD. In our study, its overall efficacy (78.3%) is greater than that reported for the presently available 3-dose vaccination (Engerix) in patients with IBD.

Hepatitis vaccination adherence and completion rates and factors associated with low compliance: A claims-based analysis of U.S. adults

Poor compliance with multi-dose vaccine schedules by adults for whom hepatitis (Hep) A and B vaccines are recommended contributes to major Hep A and B disease burdens among high-risk U.S. adults. Evidence on hepatitis vaccine series adherence, completion, timeliness of completion, and factors associated with these outcomes, is limited and not readily generalizable for U.S. adults. This retrospective, observational study examined adherence, completion, its timeliness, and the impact of sociodemographic and clinical factors on these outcomes among a large, geographically representative sample of U.S. adults. We analyzed the Optum Clinformatics SES administrative claims database (1/1/2010-6/30/2020) for recipients of 2-dose (HepA, HepB2) or 3-dose (HepB3, HepAB) hepatitis vaccines. Adherence was defined as receipt of booster doses within specified assessment periods, per label-recommended schedules. Completion (receipt of all doses) was assessed at 6, 12, 18, and 24 months.The study included 356,828 adults ≥19 years old who were continuously enrolled in a medical benefit plan for one (HepB2), six (HepB3; HepAB), or 18 months (HepA) prior to and following the index date (first observed vaccine dose). Adherence and 24-month completion rates were: HepA (27.0%, 28.4%), HepB2 (32.2%, 44.8%), HepB3 (14.3%, 37.3%), HepAB, (15.3%, 33.8%). Kaplan-Meier completion curves plateaued after about 6 months for HepB2 and about 12 months for HepA, HepB3, and HepAB vaccines. Logistic regression analyses showed risk for low adherence/completion was generally associated with male gender, younger age, Black or Hispanic race/ethnicity, lower educational or household income attainment, and more comorbidities. Adherence and completion rates for all hepatitis vaccine series are low, especially for males, younger adults, those with lower socio-economic status and more comorbidities. To our knowledge, this is the largest claims-based analysis of adherence and completion rates for U.S. adults initiating all currently available HepA and HepB vaccines. Findings may inform hepatitis vaccination programming.

Surveillance for hepatitis B virus seroprevalence nearly 30 years after the implementation of a national vaccination program

Introduction

Hepatitis B virus (HBV) infection is associated with cirrhosis and hepatocellular carcinoma. Vaccination is one aspect of public health policy aimed at eliminating HBV infection. After the implementation of an HBV vaccination program for newborns in Thailand, the estimated residual infection rate was 3.5%. However, that study was conducted in only 5,964 participants in seven provinces and only 22 years after the start of the campaign. This study aimed to evaluate the HBV seroprevalence rate in Thailand in larger sample size and a longer duration after program implementation using HBV surveillance.

Methods

This was a surveillance study conducted in 20 provinces in northeast Thailand. The study period was between July 2010 and November 2019. Rates of HBV seroprevalence in each province and overall were calculated. Participants were divided into two groups: those vaccinated under the national campaign and those who were not. Participants aged 0-20 years were used as references, while other age groups (intervals of 10 years) were comparators. Residual HBV seroprevalence after the vaccination program was calculated with odds ratio for HBV seroprevalence in each age group.

Results

There were 31,855 subjects who participated in the project. Of those, 1,805 (5.7%) had HBV. The HBV seroprevalence rate in the national HBV vaccination group was significantly lower than that in those not vaccinated under the national program (1.0% vs 5.9%; p<0.001). Seroprevalence was 1.0% in participants ≤20 years of age. Participants 31-40 years of age had the highest odds ratio (10.41), followed those 21-30 years of age (7.42).

Conclusions

This real-world surveillance study showed that residual HBV infection was 1.0% after nearly 30 years of nationwide HBV vaccination.

Considerations for estimating real-world outcomes and value in vaccination: A case study with adult hepatitis B virus vaccination

BACKGROUND

In the absence of field efficacy studies, estimating the real-world effectiveness of vaccines may consider immunogenicity from randomized controlled clinical trials and real-world adherence. Combining seroprotection rates (SPRs) with regimen completion rates gives an estimate of an effective vaccine protection rate (eVPR), which can be leveraged to evaluate real-world cost-effectiveness by linking it with vaccine costs to estimate the cost-per-protected patient (CPP).

METHODS

This study evaluated eVPR and CPP as estimates of vaccine clinical- and cost-effectiveness of two-dose (HepB-CpG) and three-dose (HepB-Alum) hepatitis B virus (HBV) vaccines in the general adult population and a subpopulation with diabetes mellitus. eVPR was calculated from head-to-head SPR data from phase 3 clinical trials directly comparing HepB-CpG and HepB-Alum vaccine regimens and real-world head-to-head adherence data. CPP was calculated as the average cost of each regimen divided by eVPR.

RESULTS

Higher eVPR in the adult population was achieved with HepB-CpG (68.0%) versus HepB-Alum (41.6%), reflecting the combination of higher SPR and vaccine regimen completion. The CPP for HepB-CpG ($331.31) was $45.67 (95% CI: $36.66, $55.19) less than HepB-Alum ($377.09). Greater savings were observed among persons with diabetes, with CPP $149.60 (95% CI: $80.29, $195.63) lower with HepB-CpG ($367.57) than HepB-Alum ($517.37).

CONCLUSIONS

Metrics estimating vaccine real-world effectiveness and value may guide informed decisions in vaccine selection. For example, using eVPR and CPP, HepB-CpG represents a more effective, value-advantaged approach than HepB-Alum toward reducing HBV infection.

Preventing hepatitis B virus infection among healthcare professionals: potential impact of a 2-dose versus 3-dose vaccine

The exposure risk to the highly infectious hepatitis B virus (HBV) is an established and recognizable hazard to healthcare professionals (HCPs). In the United States, implementing preemptive vaccination programs and safety procedures resulted in drastic reductions in HBV infections among HCPs; however, many HCPs remain unprotected and risk of exposure persists, especially among those first entering a healthcare system and undergoing professional training. First-generation HBV vaccines require completion of a 3-dose schedule over a 6-month interval for maximum immunogenicity. By comparison, HepB-CpG (HEPLISAV-B®) is a 2-dose HBV vaccine licensed in the United States in 2017, inducing rapid seroprotection over a 1-month interval and may represent a more effective strategy for combating HBV infection in US healthcare systems. In this modeling study, the health and economic impact of implementing an HBV vaccination strategy with HepB-CpG versus the 3-dose HBV vaccine (Engerix-B®) was evaluated among HCPs newly entering a healthcare system. The model used effective seroprotection rate, a real-world metric accounting for HCP vaccine compliance and seroprotection rates for different dosing regimens and considered current pricing for postexposure prophylaxis treatment. Compared with the 3-dose vaccine, HepB-CpG was anticipated to provide faster, increased protection against HBV infection among newly entered HCPs. In protecting a greater percentage of HCPs, HepB-CpG was also projected to substantially reduce the risk of HBV exposure. Accordingly, an economic analysis showed HepB-CpG vaccination would reduce costs of postexposure prophylaxis treatment compared with the 3-dose vaccine. Overall, HepB-CpG represents an effective therapeutic strategy against HBV infection for US healthcare systems.

Comparative cost-effectiveness of a 2-dose versus 3-dose vaccine for hepatitis B prevention in selected adult populations

The hepatitis B virus is highly infectious and can cause incurable liver disease, leading to high morbidity rates, increased healthcare utilization, and high mortality. Multiple preventative hepatitis B vaccine options have been available for decades, but adherence to the traditional 6-month vaccine schedule for the approved 3-dose series remains low in adult populations at risk of hepatitis B exposure. A 2-dose hepatitis B vaccine (HEPLISAV-B) approved by the US Food and Drug Administration in 2017 induces rapid seroprotection within 1 month and has a safety profile comparable to a commonly used 3-dose vaccine. In a previous cost-effectiveness study, HEPLISAV-B had a favorable cost-effectiveness profile for multiple at-risk populations. The goal of the current analysis was to update and extend previous findings by evaluating cost-effectiveness of HEPLISAV-B compared with a 3-dose vaccine (Engerix-B) in selected adult populations, including patients with diabetes, chronic liver or kidney disease, end-stage renal disease, healthcare personnel, travelers to countries with endemic hepatitis B, and a public health population. Cost-effectiveness was measured as incremental cost-effectiveness ratios using a health economics Markov model that accounts for adherence rates, seroprotection rates, healthcare costs, and current pricing considerations. Patients progressed between a series of health states, and the difference in lifetime spending and survival for individuals receiving either HEPLISAV-B or Engerix-B was estimated from the perspective of a US managed care payer, HEPLISAV-B had favorable cost-effectiveness profiles for patients with diabetes, healthcare personnel, travelers, and patients with chronic liver disease and dominant incremental cost-effectiveness ratios for patients with chronic kidney disease and end-stage renal disease. A probabilistic sensitivity analysis supported the robustness of the cost-effectiveness profiles, and an additional analysis indicated that HEPLISAV-B was cost-effective in the general adult population. Overall, HEPLISAV-B was cost-effective in multiple adult populations recommended for HBV vaccination in the United States.

CpG-Adjuvanted Hepatitis B Vaccine (HEPLISAV-B®) Update

Introduction: HEPLISAV-B is a hepatitis B vaccine composed of rHBsAg mixed with a synthetic oligonucleotide containing CpG motifs that stimulate innate immunity through TLR9. This vaccine was recently approved by FDA in view of its superior efficacy.Areas covered: Published literature on HEPLISAV-B was critically reviewed. Four randomized controlled trials among 7,056 subjects receiving 2 doses of HEPLISAV-B and 3,214 subjects receiving 3 doses of Engerix-B showed superior seroprotection rate (SPR) (anti-HBs ≥10 mIU/mL) of 90-100%, compared with 71-90% in those receiving Engerix-B. Furthermore, the seroprotection rate was also significantly higher in HEPLISAV-B compared with Engerix-B recipients in persons with traditionally poor vaccine responses such as older adults, diabetics, and those with chronic kidney disease. The safety profiles among 9,871 subjects were similar between HEPLISAV-B and Engerix-B .Expert opinion: HEPLISAV-B, a CpG adjuvant mixed with HBsAg, is more efficacious and produced earlier seroprotection compared to existing vaccines, with a favorable safety profile. The shorter, two-dose regimen, earlier seroprotection, higher adherence, and a higher seroprotection rate, especially in populations with traditionally poor vaccine response, makes this an important therapeutic option in hepatitis B vaccination.

CpG Oligonucleotides as Vaccine Adjuvants

CpG Oligonucleotides (ODN) are immunomodulatory synthetic oligonucleotides specifically designed to stimulate Toll-like receptor 9. TLR9 is expressed on human plasmacytoid dendritic cells and B cells and triggers an innate immune response characterized by the production of Th1 and pro-inflammatory cytokines. This chapter reviews recent progress in understanding the mechanism of action of CpG ODN and provides an overview of human clinical trial results using CpG ODN to improve vaccines for the prevention/treatment of cancer, allergy, and infectious disease.

Cost-Effectiveness of an Adjuvanted Hepatitis B Vaccine (HEPLISAV-B) in Patients With Inflammatory Bowel Disease

Background

Compare the cost-effectiveness of 2 recombinant hepatitis B virus (HBV) vaccines in patients with inflammatory bowel disease (IBD).

Methods

Markov models were developed for 2 IBD cohorts: (1) 40-year-old patients prior to starting IBD treatment and (2) 40-year-old patients already receiving therapy. Cohort A received full vaccination series, cohort B had primary vaccine failure and received a vaccine booster. Two vaccines were compared: adjuvanted HEPLISAV-B and nonadjuvanted Engerix-B. Clinical probabilities of acute hepatitis, chronic hepatitis, cirrhosis, fulminant hepatic failure and death, treatment costs, and effectiveness estimates were obtained from published literature. A lifetime analysis and a US payer perspective were used. Probabilistic sensitivity analyses were performed for different hypothetical scenarios.

Results

Analysis of cohort A showed moderate cost-effectiveness of HEPLISAV-B ($88,114 per quality-adjusted life year). Analysis of cohort B showed increased cost-effectiveness ($35,563 per quality-adjusted life year). Changing Engerix-B to HEPLISAV-B in a hypothetical group of 100,000 patients prevented 6 and 30 cases of acute hepatitis; and 4 and 5 cases of chronic hepatitis annually for cohorts A and B, respectively. It also prevented 1 and 2 cases of cirrhosis, and 1 and 2 deaths over 20 years for each cohort. Cost-effectiveness was determined by vaccination costs, patient age, and progression rate from chronic hepatitis to cirrhosis.

Conclusions

HEPLISAV-B is cost-effective over Engerix-B in patients receiving immunosuppressive therapy for IBD. Benefits increase with population aging and lower costs of vaccines. We advocate measuring levels of HBV antibodies in patients with IBD and favor adjuvanted vaccines when vaccination is needed.

Assessing the cost-utility of preferentially administering Heplisav-B vaccine to certain populations

Vaccination is the primary strategy to prevent hepatitis B virus (HBV) infection in the United States. Prior to 2017, most standard hepatitis B vaccine schedules required 3 doses over 6 months. Heplisav-B, approved in 2017, is administered in 2 doses over a 1 month time period but has a higher per-dose cost ($115.75 per dose compared to $57.25 per Engerix-B dose, costs as of June 1, 2019). We aimed to assess the cost-utility of providing the two-dose Heplisav-B vaccine compared to a three-dose Engerix-B vaccine among adult populations currently recommended for vaccination against hepatitis B. We used a decision-tree model with microsimulation and a Markov disease progression process to assess the cost-utility separately for the following populations: adults with diabetes, obesity, chronic kidney disease, HIV; non-responders to previous hepatitis B vaccination; older adults; and persons who inject drugs (PWID). We modeled epidemiologic outcomes (incident HBV infections, sequelae and related deaths), costs (2019 USD) and benefits (quality-adjusted life years, QALYs) and compared them across strategies. Sensitivity analyses assessed the cost-utility at varying estimates of Heplisav-B efficacy. In the base case scenario for each population, vaccination with Heplisav-B resulted in fewer HBV infections (37.5-59.8% averted), sequelae, and HBV-related deaths (36.3-71.4% averted). Heplisav-B resulted in decreased costs and increased benefits compared to Engerix-B for all populations except non-responders. Incremental costs from the baseline strategy ranged from $4746.78 saved (PWID) to $14.15 added cost (non-responders). Incremental benefits per person ranged from 0.00005 QALYs (older adults) to 0.7 QALYs (PWID). For persons with HIV and PWID, Heplisav-B resulted in lower costs and increased benefits in all scenarios in which Heplisav-B series efficacy was at least 80%. Vaccination using Heplisav-B is a cost-saving strategy compared to Engerix-B for adults with diabetes, chronic kidney disease, obesity, and HIV; older adults; and PWID.

Heplisav-B: A Hepatitis B Vaccine With a Novel Adjuvant

OBJECTIVE

To review the immunogenicity and safety of a hepatitis B vaccine containing the cytosine phosphoguanosine (CpG) 1018 adjuvant (HepB-CpG).

DATA SOURCES

Literature searches were performed using PubMed and Scopus with the search terms hepatitis B vaccine, HepB-CpG, CpG 1018, 1018-ISS, HBsAg-1018, HBV-ISS, and Heplisav. Other sources included the Centers for Disease Control, the Food and Drug Administration, the Advisory Committee on Immunization Practices (ACIP), and prescribing information.

STUDY SELECTION AND DATA EXTRACTION

Search limits included randomized controlled trial in humans and published in English from January 2003 to August 2020. Studies using the final formulation and dosing schedule were reviewed.

DATA SYNTHESIS

Studies demonstrated that 2 doses of HepB-CpG induced significantly higher seroprotective responses with a faster onset in adults, including those in hyporesponsive populations, compared with 3 doses of alum-adjuvanted Engerix-B. Although the safety profile was comparable to that of Engerix-B, one study observed higher rates of acute myocardial infarction, herpes zoster, and death with HepB-CpG.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

ACIP recommends use of HepB-CpG as an option to prevent hepatitis B virus infection in adults ≥18 years old. Higher immune responses after 2 doses make it a promising option, especially in those with risk factors for hyporesponsiveness or at risk for poor adherence to vaccine series completion. Additional data are needed regarding the vaccine's safety in the general population and the persistence of its antibody response.

CONCLUSION

HepB-CpG has been shown to be as immunogenic as Engerix-B; however, long-term safety and persistence of immune memory has yet to be established.

Expanding Antiviral Prophylaxis During Pregnancy to Prevent Perinatal Hepatitis B Virus Infection: A Cost-effectiveness Study

Background

Mother-to-child transmission (MTCT) cannot be completely prevented by the administration of active-passive immunoprophylaxis in pregnant women with hepatitis B virus (HBV) DNA levels <10⁶ copies/mL. This study will assess the economic outcomes of expanding antiviral prophylaxis in pregnant women with HBV DNA levels <10⁶ copies/mL.

Methods

A decision model was adopted to measure the economic outcomes of expanded antiviral prophylaxis at different cutoff values of HBV DNA in HBsAg(+) pregnant women in the context of the United States and China. The model inputs, including clinical, cost, and utility data, were extracted from published studies. Sensitivity analyses were carried out to examine the uncertainty of the model outputs. Quality-adjusted life-years (QALYs) and direct medical costs were expressed over a lifetime horizon.

Results

Compared with standard antiviral prophylaxis at HBV DNA ≥10⁶ copies/mL, expanded antiviral prophylaxis improved the health outcomes, and the incremental cost of expanded antiviral prophylaxis varied from $2063 in pregnant women with HBV DNA ≥10⁵ copies/mL to $14925 in all HBsAg(+) pregnant women per QALY gained in the United States, and from $1624 to $12348 in China. The model outcome was considerably influenced by the discount rate, key clinical parameters related to the incidence of MTCT, and efficacy of the prophylaxis strategy.

Conclusions

This study indicates that antiviral prophylaxis using tenofovir among pregnant women with HBV DNA <10⁶ copies/mL may be a cost-effective option, and the cutoff value of the HBV DNA load for antiviral prophylaxis needs to be tailored.

Vaccines for Health Care Personnel

Medical Center Occupational Health (MCOH) programs must protect health care personnel (HCP) against the occupational risk of vaccine-preventable diseases. This thematic review outlines the rationale for the use of recommended vaccines in HCP; summarizes the available evidence regarding vaccine effectiveness, administration, and assessment of immunity; and provides guidance for MCOH programs navigating challenging situations.

Advances in Vaccines

Vaccines represent one of the most important advances in science and medicine, helping people around the world in preventing the spread of infectious diseases. However, there are still gaps in vaccination programs in many countries. Out of 11.2 million children born in EU region, more than 500,000 infants did not receive the complete three-dose series of diphtheria, pertussis, and tetanus vaccine before the first birthday. Data shows that there were more than 30,000 measles cases in the European region in recent years, and measles cases are rising in the USA. There are about 20 million children in the world still not getting adequate coverage of basic vaccines. Emerging infectious diseases such as malaria, Ebola virus disease, and Zika virus disease also threaten public health around the world. This chapter provides an overview of recent advances in vaccine development and technologies, manufacturing, characterization of various vaccines, challenges, and strategies in vaccine clinical development. It also provides an overview of recently approved major vaccines for human use.

Nucleic acids presenting polymer nanomaterials as vaccine adjuvants

Most vaccines developed today include only the antigens that best stimulate the immune system rather than the entire virus or microbe, which makes vaccine production and use safer and easier, though they lack potency to induce acceptable immunity and long-term protection. The incorporation of additional immune stimulating components, named adjuvants, is required to generate a strong protective immune response. Nucleic acids (DNA and RNA) and their synthetic analogs are promising candidates as vaccine adjuvants activating Toll-like receptors (TLRs). Additionally, in the last few years several nanocarriers have emerged as platforms for targeted co-delivery of antigens and adjuvants. In this review, we focus on the recent developments in polymer nanomaterials presenting nucleic acids as vaccine adjuvants. We aim to compare the effectiveness of the various classes of polymers in immune modulating materials (nanoparticles, dendrimers, single-chain particles, nanogels, polymersomes and DNA-based architectures). In particular, we address the critical role of parameters such as size, shape, complexation and release of TLR ligands, cellular uptake, stability, toxicity and potential importance of spatial control in ligand presentation.

Durability of Antibody Response Against the Hepatitis B Virus in Kidney Transplant Recipients: A Proposed Immunization Guideline From a 3-Year Follow-up Clinical Study

Background

Despite the importance of hepatitis B virus (HBV) immunization in kidney transplantation (KT), data are lacking on fluctuations in hepatitis B surface antibody (anti-HBsAb) levels and optimal levels for KT recipients.

Methods

The study consisted of anti-HBsAb-positive recipients aged 18–70 years at the time of the KT. Recipients with anti-HBsAb <100 IU/L received a single booster HBV vaccination, and anti-HBsAb was measured at baseline and 3, 6, 12, 18, and 24 months post-KT. Anti-HBsAb, quantitative HBV deoxyribonucleic acid testing (12 and 24 months post-KT), and hepatitis B core-related antigen (24 months post-KT) were evaluated in recipients with anti-HBsAb >100 IU/L who received a hepatitis B surface antigen positive renal allograft.

Results

Seventy-six of 257 (29.6%) KT recipients with anti-HBsAb <100 IU/L at the time of enrollment received a single booster of HBV vaccination. Anti-HBsAb levels increased (≥100 IU/L) 1 and 3 months post-booster dose in 86% and 93% of cases, respectively. Anti-HBsAb levels were ≥100 IU/L in 95% of these recipients 6 months post-booster dose. Among 181 (70%) recipients with anti-HBsAb ≥100 IU/L without a booster dose, anti-HBsAb gradually decreased after the KT from 588 IU/L at baseline to 440 and 382 IU/L 3 and 6 months post-KT, respectively (P < .01).

Conclusions

To ensure optimal immunity against HBV, KT recipients should first be stratified according to their risk of HBV reactivation. Kidney transplantation recipients of renal allografts from HBV nonviremic or viremic donors should be reimmunized when their anti-HBsAb titers are <250 IU/L. A cutoff level of 100 IU/L is recommended in other cases.

The impact of dosing schedules on the success of vaccination programmes in elderly populations: A summary of current evidence

Vaccines are an established means of preventing and eliminating communicable diseases. Whilst their efficacy in some settings is well studied, the impact of multi-dose vaccinations programmes in elderly populations is not well documented. A literature review was conducted in order to collate and analyse existing publications to provide a summary of current thinking and support identification of key factors that impact on the success of vaccination programmes. Having returned little information to provide a comprehensive understanding of the subject area, two short surveys were undertaken to supplement the findings and further examine the attitudes and opinions of the elderly and healthcare professionals. Combining the results from all three research methodologies suggests that vaccination programmes with fewer doses are associated with improved course completion rates and a lower logistical and economic burden. Whilst it is acknowledged that this study has limitations, it provides relevant insights in a space where there is little research to inform the work programmes of vaccines in development and support optimisation of ongoing programmes. It also highlights the need for further research to fully understand the factors influencing successful vaccination programmes in this specific patient population.

Targeted outreach hepatitis B vaccination program in high-risk adults: The fundamental challenge of the last mile

BACKGROUND

The aim of this study was to evaluate the cost-effectiveness of the on-going decentralised targeted hepatitis B vaccination program for behavioural high-risk groups operated by regional public health services in the Netherlands since 1-November-2002. Target groups for free vaccination are men having sex with men (MSM), commercial sex workers (CSW) and hard drug users (HDU). Heterosexuals with a high partner change rate (HRP) were included until 1-November-2007.

METHODS

Based on participant, vaccination and serology data collected up to 31-December-2012, the number of participants and program costs were estimated. Observed anti-HBc prevalence was used to estimate the probability of susceptible individuals per risk-group to become infected with hepatitis B virus (HBV) in their remaining life. We distinguished two time-periods: 2002-2006 and 2007-2012, representing different recruitment strategies and target groups. Correcting for observed vaccination compliance, the number of future HBV-infections avoided was estimated per risk-group. By combining these numbers with estimates of life-years lost, quality-of-life losses and healthcare costs of HBV-infections - as obtained from a Markov model-, the benefit of the program was estimated for each risk-group separately.

RESULTS

The overall incremental cost-effectiveness ratio of the program was €30,400/QALY gained, with effects and costs discounted at 1.5% and 4%, respectively. The program was more cost-effective in the first period (€24,200/QALY) than in the second period (€42,400/QALY). In particular, the cost-effectiveness for MSM decreased from €20,700/QALY to €47,700/QALY.

DISCUSSION AND CONCLUSION

This decentralised targeted HBV-vaccination program is a cost-effective intervention in certain unvaccinated high-risk adults. Saturation within the risk-groups, participation of individuals with less risky behaviour, and increased recruitment investments in the second period made the program less cost-effective over time. The project should therefore discus how to reduce costs per risk-group, increase effects or when to integrate the vaccination in regular healthcare.

Real-World Data for the Evaluation of Transarterial Radioembolization versus Sorafenib in Hepatocellular Carcinoma: A Cost-Effectiveness Analysis

OBJECTIVES

To perform a cost-effectiveness analysis comparing the use of transarterial radioembolization (TARE) with that of sorafenib in the treatment of patients with intermediate or advanced hepatocellular carcinoma (HCC) according to the Barcelona Clinic Liver Cancer staging system.

METHODS

Patient-level data were consecutively recorded and collected at three oncology centers in Italy. A propensity score matching was performed to compare patients with similar clinical characteristics who underwent TARE or sorafenib treatment. Clinical data from the matched cohorts were used to populate a Markov model to project, on a lifetime horizon, life years, quality-adjusted life years, and economic outcomes associated with TARE and sorafenib for both intermediate and advanced HCC stages.

RESULTS

Starting from data covering 389 and 241 patients who underwent TARE and sorafenib treatment, respectively, the propensity score matching yielded a total of 308 matched patients. For intermediate-stage patients, the model estimated for TARE versus sorafenib an incremental cost-utility ratio of €3,302/QALY (incremental cost-effectiveness ratio of €1,865 per life year gained), whereas for patients in advanced stage TARE dominated (lower costs and greater health improvements) compared with sorafenib.

CONCLUSIONS

From an Italian health care service perspective, TARE could be a cost-effective strategy in comparison with sorafenib for patients with intermediate or advanced HCC. The results from forthcoming randomized controlled trials comparing TARE with sorafenib will be able to confirm or reject the validity of this preliminary evaluation. In the meantime, decision makers can use these results to control and coordinate the diffusion of the technology.

Economic evaluation of HBV vaccination: A systematic review of recent publications (2000-2013)

AIM

To conduct a systematic review of the economic evaluations (EE) of HBV vaccination, taking also into account the studies published in the new millennium.

METHODS

An extensive scientific literature review was conducted using two electronic medical journal databases: Scopus and PubMed engines for published studies on EE of HBV vaccination.

RESULTS

22 articles were reviewed, 9, 5 and 8 cost-effectiveness, cost-benefit and cost-utility analysis, respectively. Studies were mainly concerning EE of universal vaccination (UV), mostly with regards to low or low-medium income countries. For high income countries, EE were focused on the possible implementation of HBV vaccination in particular settings, such as diabetic, renal and other chronic conditions care, as well as infectious diseasesUV has usually a very good cost-effectiveness ratio (80%), ranging from cost-saving (China) or few Euro per LY/QALY gained (in Thailand, and Vietnam) to 630.00$/QALY in USA (Asian and Pacific Islands) Moreover, EE of HBV vaccination are favorable in the infectious diseases field as well as for chronic conditions. In relation to diabetes the studies gave controversial results.

CONCLUSION

This systematic review highlighted the importance of introducing HBV vaccination not only for infant UV program but also for other settings in which patients are people affected by communicable and non-communicable diseases.

Prophylactic vaccinations in chronic kidney disease: Current status

In this review, recent data on results concerning prophylactic vaccinations against hepatitis B virus, influenza viruses, and pneumococci are presented. Effects of active immunization in chronic kidney disease depend on category of glomerular filtration rate (GFR). The lower GFR category the better results of response to vaccination. Abnormalities in toll-like receptors and down-regulation of B-cell activating factor receptor in transitional B cells were recently included into uremia-associated deficits in immunocompetence. Development of novel, more potent vaccines containing toll-like receptor agonists as adjuvants may help to achieve more effective immunization against hepatitis B virus in immunocompromised patients. Experimental studies announce further vaccine adjuvants. A vaccine against hepatitis C virus is not available yet, but promising results were already obtained in the experimental and preliminary clinical studies. Prophylactic vaccinations against influenza viruses and pneumococci become increasingly popular in dialysis facilities due to their proved benefits.

Hepatitis B vaccination in chronic kidney disease patients: a call for novel vaccines

The protective immunization rates in response to hepatitis B vaccination in chronic kidney disease (CKD) patients are lower than response rates in the general population because of genetic and CKD-related factors as well as logistic problems with a proper providing of the recommended vaccination schedules. This review focuses on third-generation vaccines and adjuvanted vaccines commercially introduced in some countries, investigated in clinical trials, especially involving CKD patients or used only in the experimental studies. In order to improve the immunization rate, the use of third-generation vaccines (yeast-derived pre-S2/S HBV vaccines, mammalian cell-derived pre-S2/S HBV vaccines, mammalian cell-derived pre-S1/pre-S2/S HBV vaccines), novel adjuvants (AS04, AS02, phosphorothioate oligodeoxyribonucleotide, hemokinin-1, a polysaccharide based on delta inulin, nano-complex Hep-c, cyclic diguanylate) or immunostimulants for enhancement of immunogenicity of existing recombinant hepatitis B vaccines is tried to improve results of hepatitis B vaccination prior to dialysis commencement or already on renal replacement therapy.

Recent progress concerning CpG DNA and its use as a vaccine adjuvant

CpG Oligonucleotides (ODN) are immunomodulatory synthetic oligonucleotides designed to specifically agonize Toll-like receptor 9. Here, we review recent progress in understanding the mechanism of action of CpG ODN and provide an overview of human clinical trial results using CpG ODN to improve the vaccines for cancer, allergy and infectious disease.