Vaccination of immunocompromised patients

Influence of AAV vector tropism on long-term expression and Fc-γ receptor binding of an antibody targeting SARS-CoV-2

Long-acting passive immunization strategies are needed to protect immunosuppressed vulnerable groups from infectious diseases. To further explore this concept for COVID-19, we constructed Adeno-associated viral (AAV) vectors encoding the human variable regions of the SARS-CoV-2 neutralizing antibody, TRES6, fused to murine constant regions. An optimized vector construct was packaged in hepatotropic (AAV8) or myotropic (AAVMYO) AAV capsids and injected intravenously into syngeneic TRIANNI-mice. The highest TRES6 serum concentrations (511 µg/ml) were detected 24 weeks after injection of the myotropic vector particles and mean TRES6 serum concentrations remained above 100 µg/ml for at least one year. Anti-drug antibodies or TRES6-specific T cells were not detectable. After injection of the AAV8 particles, vector mRNA was detected in the liver, while the AAVMYO particles led to high vector mRNA levels in the heart and skeletal muscle. The analysis of the Fc-glycosylation pattern of the TRES6 serum antibodies revealed critical differences between the capsids that coincided with different binding activities to murine Fc-γ-receptors. Concomitantly, the vector-based immune prophylaxis led to protection against SARS-CoV-2 infection in K18-hACE2 mice. High and long-lasting expression levels, absence of anti-drug antibodies and favourable Fc-γ-receptor binding activities warrant further exploration of myotropic AAV vector-based delivery of antibodies and other biologicals.

COVID-19 Vaccination in Pregnancy: Pilot Study of Plasma MicroRNAs Associated with Inflammatory Cytokines after COVID-19 mRNA Vaccination

BACKGROUND

The impact of mRNA COVID-19 vaccines on the immunological profiles of pregnant women remains a crucial area of study. This research aims to explore the specific immunological changes triggered by these vaccines in this demographic.

METHODS

In a focused investigation, we examined the effects of mRNA COVID-19 vaccination on microRNA expression in pregnant women. Key microRNAs, including miR-451a, miR-23a-3p, and miR-21-5p, were analyzed for expression changes post-vaccination. Additionally, we assessed variations in S1RBD IgG levels and specific cytokines to gauge the broader immunological response.

RESULTS

Post-vaccination, significant expression shifts in the targeted microRNAs were observed. Alongside these changes, we noted alterations in S1RBD IgG and various cytokines, indicating an adapted inflammatory response. Notably, these immunological markers displayed no direct correlation with S1RBD IgG concentrations, suggesting a complex interaction between the vaccine and the immune system in pregnant women.

CONCLUSIONS

Our pilot study provides valuable insights into the nuanced effects of the mRNA COVID-19 vaccine on immune dynamics in pregnant women, particularly emphasizing the role of microRNAs. The findings illuminate the intricate interplay between vaccines, microRNAs, and immune responses, enhancing our understanding of these relationships in the context of pregnancy. This research contributes significantly to the growing body of knowledge regarding mRNA COVID-19 vaccines and their specific impact on maternal immunology, offering a foundation for further studies in this vital area.

De novo design of a stapled peptide targeting SARS-CoV-2 spike protein receptor-binding domain

Although effective vaccines have been developed against SARS-CoV-2, many regions in the world still have low rates of vaccination and new variants with mutations in the viral spike protein have reduced the effectiveness of most available vaccines and treatments. There is an urgent need for a drug to cure this disease and prevent infection. The SARS-CoV-2 virus enters the host cell through protein-protein interaction between the virus's spike protein and the host's angiotensin converting enzyme (ACE2). Using protein design software and molecular dynamics simulations, we have designed a 17-residue peptide (pep39), that binds to the spike protein receptor-binding domain (RBD) and blocks interaction of spike protein with ACE2. We have confirmed the binding activity of the designed peptide for the original spike protein and the delta variant spike protein using micro-cantilever and bio-layer interferometry (BLI) based methods. We also confirmed that pep39 strongly inhibits SARS-CoV-2 virus replication in Vero E6 cells. Taken together these data suggest that a newly designed spike protein RBD blocking peptide pep39 has a potential as a SARS-CoV-2 virus inhibitor.

The Burden of COVID-19 in the Immunocompromised Patient: Implications for Vaccination and Needs for the Future

Approximately 3% of US adults are immunocompromised and less capable of fighting infections such as SARS-CoV-2 (the causative agent of COVID-19). Individuals may be immunocompromised for reasons related to an underlying medical condition or to immunomodulatory therapies that alter the immune response. In general, vaccination with mRNA-based vaccines is effective at reducing COVID-19-associated hospitalization and death among immunocompromised populations, particularly after 3 or more doses. However, the immunocompromised population is heterogeneous, with COVID-19 vaccine-elicited immune responses and risk for severe COVID-19 existing on a continuum. Therefore, understanding the impact of vaccination and the complexity of immune responses across heterogeneous immunocompromised individuals is essential for guiding effective vaccination regimens including additional (booster) doses. In this article, we provide an overview of the immunocompromised population and the burden of disease attributable to COVID-19, while discussing key opportunities and challenges of vaccinating immunocompromised individuals.

Vaccination process of immunocompromised patients in the Netherlands: Current challenges and potential solutions

Introduction

Immunocompromised patients (ICP) have an increased risk for infectious diseases. Vaccines could help reduce this risk. However, ICP do not always receive or are reimbursed for the specific vaccinations on which they are dependent in the Netherlands. This research aims to gain insights into the current challenges in the vaccination process of ICP in the Netherlands. Moreover, it aims to explore potential solutions for these challenges and the ideal vaccination process.

Methods

Twelve semi-structured interviews with relevant stakeholders were conducted. Partly based on the challenges found by the Council for Health and Society (RVS) and the Dutch National Health Care Institute (ZIN) an interview guide was developed.

Results

Several newly emerged challenges were identified: fair reimbursement for the efforts of stakeholders; circular reasoning of vaccine reimbursement and guidelines; suboptimal translation from guidelines to practice and no smooth-running infrastructure. Most challenges corresponded with those stated by the RVS and ZIN. Affordability and knowledge deficit in healthcare providers and patients were the most important challenges. Rarely the same solutions were mentioned, and no ideal vaccination process emerged.

Conclusions

The various challenges in the vaccination process of ICP in the Netherlands implies the difficulty to solve the problem. It is recommended to focus on solving the most important challenges. A potential solution is to adjust the GVS registration process to make it easier for the pharmaceutical industry to apply for reimbursement towards various high-risk groups. Additionally, vaccination should have a more prominent role in the education of healthcare providers. Furthermore, stakeholders need to cooperate more to solve the reimbursement and guidelines issue.

Review of the unmet medical need for vaccination in adults with immunocompromising conditions: An Indian perspective

Immunocompromised (IC) populations are at increased risk of vaccine-preventable diseases (VPDs). In India, the concern of VPDs in IC populations is particularly acute due to the prevalence of crowded living situations, poor sanitation and variable access to healthcare services. We present a narrative review of IC-related disease and economic burden, risk of VPDs and vaccination guidelines, based on global and India-specific literature (2000-2022). IC conditions considered were cancer, diabetes mellitus, chronic kidney disease, respiratory disorders, disorders treated with immunosuppressive therapy, and human immune deficiency virus (HIV). The burden of IC populations in India is comparable to the global population, except for cancer and HIV, which have lower prevalence compared with the global average. Regional and socioeconomic inequalities exist in IC prevalence; VPDs add to the burden of IC conditions, especially in lower income strata. Adult vaccination programs could improve health and reduce the economic impact of VPDs in IC populations.

Pediatric cancer care management during the COVID-19 pandemic: a review of the literature and a single-centre real-life experience of an Italian pediatric oncology unit

INTRODUCTION

The severe acute respiratory syndrome coronavirus-2 pandemic significantly affected clinical practice, also in pediatric oncology units. Cancer patients needed to be treated with an adequate dose density despite the SARS-CoV-2 infection, balancing risks of developing severe COVID-19 disease.

AREAS COVERED

Although the pandemic spread worldwide, the prevalence of affected children was low. The percentage of children with severe illness was approximately 1-6%. Pediatric cancer patients represent a prototype of a previously healthy immune system that is hampered by the tumor itself and treatments, such as chemotherapy and steroids. Through a review of the literature, we reported the immunological basis of the response to SARS-CoV-2 infection, the existing antiviral treatments used in pediatric cancer patients, and the importance of vaccination. In conclusion, we reported the real-life experience of our pediatric oncology unit during the pandemic period.

EXPERT OPINION

Starting from the data available in literature, and our experience, showing the rarity of severe COVID-19 disease in pediatric patients with solid tumors, we recommend carefully tailoring all the oncological treatments (chemotherapy/targeted therapy/stem cell transplantation/radiotherapy). The aim is the preservation of the treatment's timing, balanced with an evaluation of possible severe COVID-19 disease.

Mucosal Vaccination Strategies against Clostridioides difficile Infection

Clostridioides difficile infection (CDI) presents a major public health threat by causing frequently recurrent, life-threatening cases of diarrhea and intestinal inflammation. The ability of C. difficile to express antibiotic resistance and to form long-lasting spores makes the pathogen particularly challenging to eradicate from healthcare settings, raising the need for preventative measures to curb the spread of CDI. Since C. difficile utilizes the fecal-oral route of transmission, a mucosal vaccine could be a particularly promising strategy by generating strong IgA and IgG responses that prevent colonization and disease. This mini-review summarizes the progress toward mucosal vaccines against C. difficile toxins, cell-surface components, and spore proteins. By assessing the strengths and weaknesses of particular antigens, as well as methods for delivering these antigens to mucosal sites, we hope to guide future research toward an effective mucosal vaccine against CDI.

The Impact of COVID-19 on Pediatric Malignancy Diagnosis and Treatment: Never the Same but Lessons Learned

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic affected the pediatric oncology population globally. Over the course of 2 years, increasing reports have been made to better understand this entity and its pathologic complications on these patients. The pandemic has allowed healthcare providers, hospital systems, and leading oncologic societies to quickly adapt and formulate new guidelines for the effective understanding, management, and treatment of patients with pediatric malignancy.

Exploring Vaccination Sentiments: A Population-Centric Examination

Vaccine hesitancy has, for a considerable time, been a significant risk to global health. As an integral part of disease prevention, vaccines have become a public health matter which is often debated among the community in spite of proven scientific evidence of their efficiency. A questionnaire was designed to evaluate the perception and knowledge of a population and compare it with behavior in order to assess a demographic within a sample population of 245 individuals selected at random within the United States, Here, we aim to clarify the difference between vaccine opinion among the general public as compared to vaccination status. Chi-squared analysis was done with the categorical data showing a statistically significant result when comparing parents versus non-parents, and Asian/Asian Americans against other ethnicities. All other comparisons were statistically insignificant. When looking at participant responses, PCPs did not discuss vaccines at all with 32% of the sample. The need for PCPs to provide educational information to certain ethnicities may play an important role in public health.

Intralesional Versus Intramuscular Hepatitis B Virus Vaccine in the Treatment of Multiple Common Warts

BACKGROUND

Hepatitis B virus (HBV) vaccination is associated with stimulation of humoral and cell-mediated immunity. Intralesional HBV vaccine has been recently used as an immunotherapy of common warts with relatively low success rate.

AIM

To assess the efficacy and safety of intralesional versus intramuscular (IM) HBV vaccine in the treatment of multiple common warts.

PATIENTS AND METHODS

The study included 60 patients with multiple common warts who were randomly assigned to 2 groups: intralesional HBV vaccine or IM HBV vaccine. In the intralesional HBV vaccine group, the vaccine was injected into the largest wart at 2-week intervals until complete clearance or for a maximum of 5 sessions. Intramuscular HBV vaccine group received 3 injections in the deltoid muscle at 0, 1, and 6 months.

RESULTS

Complete wart clearance was reported in 7 patients (23.3%) of the intralesional HBV vaccine group and 15 patients (50%) of the IM HBV vaccine group. The difference was statistically significant in favor of the IM group ( p = .0479). Adverse effects were mild and insignificant in the 2 groups.

CONCLUSION

HBV vaccine, particularly the IM form seems to be a promising, well-tolerated therapeutic option for the treatment of warts.

LIMITATIONS

Short follow-up period and small sample size.

Design of a multi-epitope vaccine against the pathogenic fungi Candida tropicalis using an in silico approach

Background

Candida tropicalis causes tropical invasive fungal infections, with a high mortality. This fungus has been found to be resistant to antifungal classes such as azoles, echinocandins, and polyenes in several studies. As a result, it is vital to identify novel approaches to prevent and treat C. tropicalis infections. In this study, an in silico technique was utilized to deduce and evaluate a powerful multivalent epitope-based vaccine against C. tropicalis, which targets the secreted aspartic protease 2 (SAP2) protein. This protein is implicated in virulence and host invasion.

Results

By focusing on the Sap2 protein, 11 highly antigenic, non-allergic, non-toxic, and conserved epitopes were identified. These were subsequently paired with RS09 and flagellin adjuvants, as well as a pan HLA DR-binding epitope (PADRE) sequence to create a vaccine candidate that elicited both cell-mediated and humoral immune responses. It was projected that the vaccine design would be soluble, stable, antigenic, and non-allergic. Ramachandran plot analysis was applied to validate the vaccine construct’s 3-dimensional model. The vaccine construct was tested (at 100 ns) using molecular docking and molecular dynamics simulations, which demonstrated that it can stably connect with MHC-I and Toll-like receptor molecules. Based on in silico studies, we have shown that the vaccine construct can be expressed in E. coli. We surmise that the vaccine design is unrelated to any human proteins, indicating that it is safe to use.

Conclusions

The vaccine design looks to be an effective option for preventing C. tropicalis infections, based on the outcomes of the studies. A fungal vaccine can be proposed as prophylactic medicine and could provide initial protection as sometimes diagnosis of infection could be challenging. However, more in vitro and in vivo research is needed to prove the efficacy and safety of the proposed vaccine design.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00415-3.

Answers to common questions about COVID-19 vaccines in children with cancer

BACKGROUND

The SARS-CoV-2 outbreak in 2020 evolved into a global pandemic, and COVID-19 vaccines became rapidly available, including for pediatric patients. However, questions emerged that challenged vaccine acceptance and use. We aimed to answer these questions and give recommendations applicable for use in pediatric patients with cancer by healthcare professionals and the public.

METHODS

A 12-member global COVID-19 Vaccine in Pediatric Oncology Working Group made up of physicians and nurses from all world regions met weekly from March to July 2021. We used a modified Delphi method to select the top questions. The Working Group, in four-member subgroups, answered assigned questions by providing brief recommendations, followed by a discussion of the rationale for each answer. All Working Group members voted on each recommendation using a scale of 1 to 10, 10 being complete agreement. A "pass" recommendation corresponded to an agreement ≥7.5.

RESULTS

We selected 15 questions from 173 suggested questions. Based on existing published information, we generated answers for each question as recommendations. The overall average agreement for the 24 recommendations was 9.5 (95% CI 9.4-9.6).

CONCLUSION

Top COVID-19 vaccine-related questions could be answered using available information. Reports on COVID-19 vaccination and related topics have been published at record speed, aided by available technology and the priority imposed by the pandemic; however, all efforts were made to incorporate emerging information throughout our project. Recommendations will be periodically updated on a dedicated website.

Computer-Aided Tools and Resources for Fungal Pathogens: An Application of Reverse Vaccinology for Mucormycosis

Increasing fungal infections in immunocompromised hosts are a growing concern for global public health. Along with treatments, preventive measures are required. The emergence of reverse vaccinology has opened avenues for using genomic and proteomic data from pathogens in the design of vaccines. In this work, we present a comprehensive collection of various computational tools and databases with potential to aid in vaccine development. The ongoing pandemic has directed attention toward the increasing number of mucormycosis infections in COVID-19 patients. As a case study, we developed a computational pipeline for assisting vaccine development for mucormycosis. We obtained 6 proteins from 29,447 sequences from UniProtKB as potential vaccine candidates against mucormycosis, fulfilling multiple criteria. These criteria included potential characteristics, namely adhesin properties, surface or extracellular localization, antigenicity, no similarity to any human proteins, nonallergenicity, stability in vitro, and expression in fungal cells. These six proteins were predicted to have B cell and T cell epitopes, proinflammatory inducing peptides, and orthologs in several mucormycosis-causing species. These data could aid in vaccine development against mucormycosis for at-risk individuals.

Post-exposure prophylaxis to prevent varicella in immunocompromised children

Background

Varicella-zoster virus (VZV) infection can cause life-threatening events in immunocompromised patients. Post-exposure prophylaxis (PEP) is required to prevent secondary VZV infection. Limited evidence is available for the use of acyclovir (ACV)/valacyclovir (VCV) as PEP.

Methods

Herein, we retrospectively analyzed immunocompromised paediatric patients with significant exposure to VZV. Patients administered PEP were categorized into four groups: 1) ACV/VCV group; 2) intravenous immunoglobulin (IVIG) group; 3) ACV/VCV/IVIG group; 4) vaccine group.

Results

Among 69 exposure events, 107 patients were administered PEP (91, ACV/VCV; 16, ACV/VCV/IVIG) and 10 patients did not receive PEP (non-PEP group). The index case was diagnosed based on clinical symptoms in 55 cases (79.7%). Fourteen cases (20.3%) were confirmed using direct virological diagnostic procedures. In the PEP group, only 2 patients (2.2%) developed secondary VZV infections. Additionally, 2 patients in the non-PEP group (20.0%) developed secondary VZV infection. The incidence of secondary VZV infection was significantly lower in the PEP group than in the non-PEP group (P=0.036). Among patients administered PEP, no antiviral drug-induced side effects were detected.

Conclusions

Antiviral agents administered as PEP are effective and safe for preventing VZV infections in immunocompromised patients. Rapid virological diagnosis of index cases might allow efficient administration of PEP after significant exposure to VZV infection.

Vaccination of Immunocompromised Cats

Immunocompromise is a common condition in cats, especially due to widespread infections with immunosuppressive viruses, such as feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV), but also due to chronic non-infectious diseases, such as tumours, diabetes mellitus, and chronic kidney disease, as well as treatment with immunosuppressive drugs, such as glucocorticoids, cyclosporins, or tumour chemotherapy. In this review, the European Advisory Board on Cat Diseases (ABCD), a scientifically independent board of experts in feline medicine from eleven European countries, discusses the current knowledge and rationale for vaccination of immunocompromised cats. So far, there are few data available on vaccination of immunocompromised cats, and sometimes studies produce controversial results. Thus, this guideline summarizes the available scientific studies and fills in the gaps with expert opinion, where scientific studies are missing. Ultimately, this review aims to help veterinarians with their decision-making in how best to vaccinate immunocompromised cats.

Qualitative assessment of anti-SARS-CoV-2 spike protein immunogenicity (QUASI) after COVID-19 vaccination in older people living with HIV

Objectives

Effective and safe COVID‐19 vaccines have been developed and have resulted in decreased incidence and severity of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and can decrease secondary transmission. However, there are concerns about dampened immune responses to COVID‐19 vaccination among immunocompromised patients, including people living with HIV (PLWH), which may blunt the vaccine's efficacy and durability of protection. This study aimed to assess the qualitative SARS‐CoV‐2 vaccine immunogenicity among PLWH after vaccination.

Methods

We conducted targeted COVID‐19 vaccination (all received BNT162b2 vaccine) of PLWH (aged ≥ 55 years per state guidelines) at Yale New Haven Health System and established a longitudinal survey to assess their qualitative antibody responses at 3 weeks after the first vaccination (and prior to receipt of the second dose of the COVID‐19 vaccine) (visit 1) and at 2–3 weeks after the second vaccination (visit 2) but excluded patients with prior COVID‐19 infection. Our goal was to assess vaccine‐induced immunity in the population we studied. Qualitative immunogenicity testing was performed using Healgen COVID‐19 anti‐Spike IgG/IgM rapid testing. Poisson regression with robust standard errors was used to determine factors associated with a positive IgG response.

Results

At visit 1, 45 of 78 subjects (57.7%) tested positive for SARS‐CoV‐2 anti‐Spike IgG after the first dose of COVID‐19 vaccine. Thirty‐nine subjects returned for visit 2. Of these, 38 had positive IgG (97.5%), including 20 of 21 subjects (95.2%) with an initial negative anti‐Spike IgG. Our bivariate analysis suggested that participants on an antiretroviral regimen containing integrase strand transfer inhibitors [relative risk (RR) = 1.81, 95% confidence interval (CI): 0.92–3.56, p = 0.085] were more likely to seroconvert after the first dose of the COVID‐19 vaccine, while those with a CD4 count < 500 cells/μL (RR = 0.59, 95% CI: 0.33–1.05, p = 0.071), and those diagnosed with cancer or another immunosuppressive condition (RR = 0.49, 95% CI: 0.18–1.28, p = 0.15) may have been less likely to seroconvert after the first dose of the COVID‐19 vaccine. The direction of these associations was similar in the multivariate model, although none of these findings reached statistical significance (RR_{integrase inhibitor} = 1.71, 95% CI: 0.90–3.25, p = 0.10; RR_{CD4 count} = 0.68, 95% CI: 0.39–1.19, p = 0.18; RR_{cancer or another immunosuppressive condition} = 0.50, 95% CI: 0.19–1.33, p = 0.16). With regard to immunogenicity, we were able to record very high rates of new seroconversion following the second dose of the COVID‐19 vaccine.

Conclusions

Our study suggests that completing a two‐dose series of BNT162b2 vaccine is critical for PLWH given suboptimal seroconversion rates after the first dose and subsequent improved seroconversion rates after the second dose.

B-Cell Immunophenotyping to Predict Vaccination Outcome in the Immunocompromised - A Systematic Review

Vaccination is the most effective measure to prevent infections in the general population. Its efficiency strongly depends on the function and composition of the immune system. If the immune system lacks critical components, patients will not be fully protected despite a completed vaccination schedule. Antigen-specific serum immunoglobulin levels are broadly used correlates of protection. These are the products of terminally differentiated B cells - plasma cells. Here we reviewed the literature on how aberrancies in B-cell composition and function influence immune responses to vaccinations. In a search through five major literature databases, 6,537 unique articles published from 2000 and onwards were identified. 75 articles were included along three major research lines: extremities of life, immunodeficiency and immunosuppression. Details of the protocol can be found in the International Prospective Register of Systematic Reviews [PROSPERO (registration number CRD42021226683)]. The majority of articles investigated immune responses in adults, in which vaccinations against pneumococci and influenza were strongly represented. Lack of baseline information was the most common reason of exclusion. Irrespective of study group, three parameters measured at baseline seemed to have a predictive value in assessing vaccine efficacy: (1) distribution of B-cell subsets (mostly a reduction in memory B cells), (2) presence of exhausted/activated B cells, or B cells with an aberrant phenotype, and (3) pre-existing immunological memory. In this review we showed how pre-immunization (baseline) knowledge of circulating B cells can be used to predict vaccination efficacy. We hope that this overview will contribute to optimizing vaccination strategies, especially in immunocompromised patients.

In vitro antiviral activity of peptide-rich extracts from seven Nigerian plants against three non-polio enterovirus species C serotypes

Background

As frequent viral outbreaks continue to pose threat to public health, the unavailability of antiviral drugs and challenges associated with vaccine development underscore the need for antiviral drugs discovery in emergent moments (endemic or pandemic). Plants in response to microbial and pest attacks are able to produce defence molecules such as antimicrobial peptides as components of their innate immunity, which can be explored for viral therapeutics.

Methods

In this study, partially purified peptide-rich fraction (P-PPf) were obtained from aqueous extracts of seven plants by reverse-phase solid-phase extraction and cysteine-rich peptides detected by a modified TLC method. The peptide-enriched fractions and the aqueous (crude polar) were screened for antiviral effect against three non-polio enterovirus species C members using cytopathic effect reduction assay.

Results

In this study, peptide fraction obtained from Euphorbia hirta leaf showed most potent antiviral effect against Coxsackievirus A13, Coxsackievirus A20, and Enterovirus C99 (EV-C99) with IC₅₀ < 2.0 µg/mL and selective index ≥ 81. EV-C99 was susceptible to all partially purified peptide fractions except Allamanda blanchetii leaf.

Conclusion

These findings establish the antiviral potentials of plants antimicrobial peptides and provides evidence for the anti-infective use of E. hirta in ethnomedicine. This study provides basis for further scientific investigation geared towards the isolation, characterization and mechanistic pharmacological study of the detected cysteine-rich peptides.

The current state of immunization against Gram-negative bacteria in children: a review of the literature

PURPOSE OF REVIEW

Gram-negative bacteria (GNB) are a major cause of infection worldwide and multidrug resistance in infants and children. The major pathogens include Klebsiella pneumoniae, Escherichia coli, Enterobacter spp., Pseudomonas aeruginosa and Acinetobacter baumannii. With new antibiotic options limited, immunization is likely to play a critical role in prevention. This review discusses their epidemiology, the current state of vaccine research and potential immunization strategies to protect children. A comprehensive review of the literature, conference abstracts along with web searches was performed to identify current and investigational vaccines against the major GNB in children.

RECENT FINDINGS

Phase I--III vaccine trials have been undertaken for the major Gram-negative bacteria but not in infants or children. E. coli is a common infection in immune-competent children, including neonatal sepsis. Several vaccines are in late-phase clinical trials, with some already licensed for recurrent urinary tract infections in women. Klebsiella spp. causes community-acquired and hospital-acquired infections, including sepsis in neonates and immunocompromised children although no vaccine trials have extended beyond early phase 2 trials. P. aeruginosa is a common pathogen in patients with cystic fibrosis. Phase 1--3 vaccine and monoclonal antibody trials are in progress, although candidates provide limited coverage against pathogenic strains. Enterobacter spp. and A. baumannii largely cause hospital-acquired infections with experimental vaccines limited to phase 1 research.

SUMMARY

The current immunization pipelines for the most prevalent GNB are years away from licensure. Similar to incentives for new antibiotics, global efforts are warranted to expedite the development of effective vaccines.

COVID-19 Vaccine and Hematopoietic Stem Cell Transplantation

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Safety Profile of the Adjuvanted Recombinant Zoster Vaccine in Immunocompromised Populations: An Overview of Six Trials

Introduction

The adjuvanted recombinant zoster vaccine (RZV) has demonstrated high efficacy against herpes zoster in older adults and immunocompromised populations. We present comprehensive safety data from six clinical trials in immunocompromised populations (autologous hematopoietic stem cell transplant and renal transplant recipients, patients with hematologic malignancies, patients with solid tumors, and human immunodeficiency virus-infected adults) who are at an increased risk of herpes zoster.

Methods

In all trials, immunocompromised adults ≥ 18 years of age were administered RZV or placebo. Safety was evaluated in the total vaccinated cohort. Solicited adverse events (AEs) were collected for 7 days and unsolicited AEs for 30 days after each dose. Serious AEs, fatal serious AEs, and potential immune-mediated diseases were collected from dose 1 until 12 months post-last dose or study end. Data were pooled for solicited AEs; unsolicited AEs, (fatal) serious AEs, and potential immune-mediated diseases were analyzed for each individual trial. All AEs were analyzed for sub-strata of adults 18–49 years of age and ≥ 50 years of age.

Results

In total, 1587 (RZV) and 1529 (placebo) adults were included in the pooled total vaccinated cohort. Solicited AEs were more common after RZV than placebo, were generally more common in the younger age stratum, and were mostly mild to moderate and resolved within 3 days (median duration). Unsolicited AEs and serious AEs were in line with underlying diseases and therapies. Across studies, the percentage of adults reporting one or more unsolicited AE was comparable between RZV and placebo, irrespective of age stratum. The percentage of adults reporting one or more serious AE, fatal serious AE, or potential immune-mediated diseases was generally similar for RZV and placebo, irrespective of age stratum. Overall, no safety concerns were identified.

Conclusions

Recombinant zoster vaccine has a clinically acceptable safety profile. With the previously published vaccine efficacy and immunogenicity results, these data support a favorable benefit-risk profile of RZV vaccination in immunocompromised populations who are at an increased risk of herpes zoster.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-021-01076-w.

Varicella zoster virus leads to chickenpox after primary infection and herpes zoster upon reactivation of the latent virus. Older adults and immunocompromised people, whose immune system is impaired because of the age-related decline in immunity and their underlying disease and/or treatment, respectively, are at an increased risk of herpes zoster and its complications. Recombinant zoster vaccine has been approved to prevent herpes zoster and its complications in adults aged ≥ 50 years in over 30 countries. In Europe, the vaccine has recently received approval to expand its use in adults aged 18 years or older who are at an increased risk of herpes zoster. We present an overview of the safety data from six clinical trials in immunocompromised patients vaccinated with recombinant zoster vaccine. We found that solicited adverse events were more common after the vaccine than placebo but that these were mild to moderate in intensity. Furthermore, the frequency of unsolicited adverse events was similar between the vaccine and placebo, and most of the reported adverse events and severe adverse events (e.g., infections or tumors) could be attributed to the pre-existent diseases and/or therapies. As such, no safety concern was identified following the review of the available clinical data. This overview, together with the published efficacy data in the prevention of herpes zoster and the vaccine immunogenicity, provides useful medical information and supports the use of the recombinant zoster vaccine in an immunocompromised population at an increased risk of herpes zoster.

COVID-19 Vaccination in Patients with Classic Kaposi's Sarcoma

The novel coronavirus disease 2019 (COVID-19) has represented an overwhelming challenge for worldwide health systems. Patients with cancer are considered at higher risk for severe COVID-19 and increased mortality in case of infection. Although data on the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in patients with cancer are limited, there is enough evidence supporting anti-infective vaccination in general in patients with active cancer, or with history of previous malignancy. Subjects with classic Kaposi's sarcoma (KS) represent a small subset of cancer patients, which should be considered at heightened risk for infections due to several factors including age, and impaired immune function status. Several cases of human herpesviruses reactivation among critically ill COVID-19 patients have been described. Moreover, in case of severe infection and treatment with immunomodulating agents, patients with CKS are exposed at significant risk of viral reactivation and disease progression. Considering the baseline clinical risk factors of patients with CKS, and the complex interplay of the two viral agents, SARS-CoV-2 vaccination should be strongly recommended among patients with KS. KS represents an interesting field to study the interactions among chronic viral infections, SARS-CoV-2 and the host's immune system. Prospective observational studies are needed to provide more insights on vaccine activity and safety among patients with cancer, optimal vaccine schedules, potential interactions with antineoplastic therapies, and other comorbidities including chronic viral infections.

A Review of Vaccinations in Adult Patients with Secondary Immunodeficiency

Vaccine-preventable diseases and their related complications are associated with increased morbidity and mortality in patients with altered immunocompetence. Optimised immunisation in this patient population is challenging because of limited data from vaccine trials, suboptimal vaccine efficacy and safety concerns. Reliable efficacy data are lacking among patients with altered immunocompetence, and existing recommendations are mainly based on expert consensus and may vary geographically. Inactivated vaccines can be generally used without risks in this group, but their efficacy may be reduced, and immunisation schedules vary according to local guidelines, age, and type and stage of the underlying disease. Live vaccines, if indicated, should be administered with care because of the risk of vaccine-associated disease. We have reviewed the current evidence on vaccination principles and recommendations in adult patients with secondary immunodeficiencies, including asplenia, HIV infection, stem cell and solid organ transplant, haematological malignancies, inflammatory bowel disease and other chronic disorders.

Safety and immunogenicity of a first dose of SARS-CoV-2 mRNA vaccine in allogeneic hematopoietic stem-cells recipients

This was a monocentric prospective study testing the efficacy and safety of a first injection of BNT162b2 (Pfizer‐BioNTech) in 112 Allo‐HSCT patients. Antibody response to SARS‐CoV‐2 spike protein receptor‐binding domain was tested at the time of the second injection (Roche Elecsys). The study also included a non‐randomized control arm of 26 healthy controls. This study shows that a first dose of SARS‐CoV‐2 messenger RNA vaccine is safe and provides a 55% rate of seroconversion in allotransplanted patients compared to 100% for the controls (p < 0.001). Factors influencing the absence of response in patients were recent transplantation (<2 years), lymphopenia (<1 × 10⁹/L) and immunosuppressive treatment or chemotherapy at the time of vaccination.

Vaccines for human fungal diseases: close but still a long way to go

Despite the substantial global burden of human fungal infections, there are no approved fungal vaccines to protect at risk individuals. Here, we review the progress that has been made and the challenges that lie ahead in the quest towards efficacious fungal vaccines. In mouse studies, protection has been achieved with vaccines directed against fungal pathogens, including species of Candida, Cryptococcus, and Aspergillus, that most commonly cause life-threatening human disease. Encouraging results have been obtained with vaccines composed of live-attenuated and killed fungi, crude extracts, recombinant subunit formulations, and nucleic acid vaccines. Novel adjuvants that instruct the immune system to mount the types of protective responses needed to fight mycotic infections are under development. Candidate vaccines include those that target common antigens expressed on multiple genera of fungi thereby protecting against a broad range of mycoses. Encouragingly, three vaccines have reached human clinical trials. Still, formidable obstacles must be overcome before we will have fungal vaccines licensed for human use.

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).

Vaccination with Messenger RNA: A Promising Alternative to DNA Vaccination

The first proof-of-concept studies about the feasibility of genetic vaccines were published over three decades ago, opening the way for future development. The idea of nonviral antigen delivery had multiple advantages over the traditional live or inactivated pathogen-based vaccines, but a great deal of effort had to be invested to turn the idea of genetic vaccination into reality. Although early proof-of-concept studies were groundbreaking, they also showed that numerous aspects of genetic vaccines needed to be improved. Until the early 2000s, the vast majority of effort was invested into the development of DNA vaccines due to the potential issues of instability and low in vivo translatability of messenger RNA (mRNA). In recent years, numerous studies have demonstrated the outstanding abilities of mRNA to elicit potent immune responses against infectious pathogens and different types of cancer, making it a viable platform for vaccine development. Multiple mRNA vaccine platforms have been developed and evaluated in small and large animals and humans and the results seem to be promising. RNA-based vaccines have important advantages over other vaccine approaches including outstanding efficacy, safety, and the potential for rapid, inexpensive, and scalable production. There is a substantial investment by new mRNA companies into the development of mRNA therapeutics, particularly vaccines, increasing the number of basic and translational research publications and human clinical trials underway. This review gives a broad overview about genetic vaccines and mainly focuses on the past and present of mRNA vaccines along with the future directions to bring this potent vaccine platform closer to therapeutic use.

Immune Status Against Hepatitis B in Patients After Allogeneic Hematopoietic Cell Transplantation-Factors Affecting Early and Long-Lasting Maintenance of Protective Anti-HBs Titers

The immunization of allogeneic hematopoietic cell transplantation (HCT) recipients against vaccine-preventable diseases is a part of posttransplantation guidelines. We conducted a prospective study to assess clinical and immunological parameters that would determine the response and long-term maintenance of protective antibody titers upon the hepatitis B virus (HBV) vaccination after HCT. The investigated variables included: vaccination of the HCT recipients and their donors prior to HCT, chronic graft versus host disease (cGVHD) and the timing of post-HCT vaccination, and B- and T-cell subtype status. Forty-two patients were immunized with three or more doses of recombinant hepatitis B surface antigen (rHBsAg) administered according to the individualized schedule of 0-1-2-6-(12) months. After vaccination, seroconversion was achieved in the whole group. The vaccines were categorized according to the antibody (Ab) titers as weak (WRs; 28.7%), good (GRs; 38%) or very good responders (VGRs; 3.3%). In multivariate logistic regression, severe cGVHD (OR= 15.5), and preceding donor immunization (OR= 0.13) were independent predictors of a weak response to vaccination. A prior belonging to the WR group impaired the durability of protection (OR= 0.17) at a median follow-up of 11.5 years. Patients with severe cGVHD showed a trend toward lower median Ab titers, although they required a higher rate of booster vaccine doses. All VGRs had CD4+ cells > 0.2 x 10⁶/L. There was a lower mean rate of CD4+IL2+ lymphocytes in WRs. Vaccination demonstrated the immunomodulatory effect on B-cell and T-cell subsets and a Th1/Th2 cytokine profile, while shifts depended on a history of severe cGVHD and the type of vaccine responder. To conclude, vaccination of HCT donors against HBV allows a better response to vaccination in the respective HCT recipients. Double doses of rHBsAg should be considered in patients with cGVHD and in those not immunized before HCT. A dedicated intensified vaccination schedule should be administered to WRs.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

Specific donor HLA allotypes as predictors of cytomegalovirus disease risk in acute myeloid leukemia

Some HLA alleles have been shown to be associated with susceptibility to cytomegalovirus (CMV) disease incidence in vitro. The objective of this study was to identify correlations between donor HLA allotypes and CMV disease incidence in patients with acute myeloid leukemia who had undergone allogeneic hematopoietic stem cell transplantation (HSCT). Methods and materials we retrospectively analyzed the medical records of 613 donors and recipients with acute myeloid leukemia who had received an allogeneic HSCT from matched sibling (n = 260), unrelated (n = 168), or haploidentical (n = 186) donors, from 2012 to 2017. The HLA-A, -B, -C, and -DRB1 allotypes in the donors were determined using sequence-based typing. Overall, CMV disease incidence was significantly associated with three genotype alleles, HLA-A*30:04:01G, -B*51:01:01G, and -DRB1*09:01:02G. In the donor CMV IgG seropositive subgroup, CMV disease incidence was significantly associated with HLA-B*51:01:01G and -DRB1*09:01:02G. In the IgG seropositive donors in the unrelated allo-HSCT subgroup CMV disease incidence was also significantly associated with HLA-B*51:01:01G. In the CMV seropositive donors in the haploidentical allo-HSCT subgroup, the incidence of CMV disease was significantly associated with HLA-A*24:02:01G and -DRB1*09:01:02G. HLA-DRB1*13:02:01G was a protective marker among IgG seropositive donors in the unrelated allo-HSCT recipient category. Discussion and conclusions The incidence of CMV disease among HSCT recipients varies according to donor HLA alleles and the donor CMV IgG serostatus. Certain donor HLA alleles can be considered to be risk or protective markers. Donors' HLA types and CMV IgG serostatus should be considered in donor selection.

Evaluation of the immune memory response to routine HBV vaccine in Egyptian patients with Type 1 diabetes

We aimed to evaluate the immune memory response to HBV vaccine in diabetic patients who had received the full HBV vaccination during infancy and to assess the need for booster doses. Blood samples were collected from children (93 diabetics and 105 controls) and university students (22 diabetics and 20 controls). Anti-HBs titer in serum and after in vitro stimulation of peripheral blood mononuclear cells with HBV vaccine was measured by ELISA. Diabetic groups had significantly lower anti-HBs levels after 10 years of the last HBV vaccine dose. The percentage of diabetic patients having protective anti-HBs titers was significantly lower than controls. In conclusion, diabetic patients had lower immune response to HBV vaccine over time, emphasizing the need for a booster dose.

Anti-infective vaccination strategies in patients with hematologic malignancies or solid tumors-Guideline of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO)

Infectious complications are a significant cause of morbidity and mortality in patients with malignancies specifically when receiving anticancer treatments. Prevention of infection through vaccines is an important aspect of clinical care of cancer patients. Immunocompromising effects of the underlying disease as well as of antineoplastic therapies need to be considered when devising vaccination strategies. This guideline provides clinical recommendations on vaccine use in cancer patients including autologous stem cell transplant recipients, while allogeneic stem cell transplantation is subject of a separate guideline. The document was prepared by the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO) by reviewing currently available data and applying evidence-based medicine criteria.

Immunogenicity and safety of the adjuvanted recombinant zoster vaccine in adults with haematological malignancies: a phase 3, randomised, clinical trial and post-hoc efficacy analysis

BACKGROUND

The adjuvanted recombinant zoster vaccine (Shingrix) can prevent herpes zoster in older adults and autologous haemopoietic stem cell transplant recipients. We evaluated the safety and immunogenicity of this vaccine in adults with haematological malignancies receiving immunosuppressive cancer treatments.

METHODS

In this phase 3, randomised, observer-blind, placebo-controlled study, done at 77 centres worldwide, we randomly assigned (1:1) patients with haematological malignancies aged 18 years and older to receive two doses of the adjuvanted recombinant zoster vaccine or placebo 1-2 months apart during or after immunosuppressive cancer treatments, and stratified participants according to their underlying diseases. The co-primary objectives of the study were the evaluation of safety and reactogenicity of the adjuvanted recombinant zoster vaccine compared with placebo from the first vaccination up to 30 days after last vaccination in all participants; evaluation of the proportion of participants with a vaccine response in terms of anti-glycoprotein E humoral immune response to the adjuvanted recombinant zoster vaccine at month 2 in all participants, excluding those with non-Hodgkin B-cell lymphoma and chronic lymphocytic leukaemia; and evaluation of the anti-glycoprotein E humoral immune responses to the vaccine compared with placebo at month 2 in all participants, excluding those with non-Hodgkin B-cell lymphoma and chronic lymphocytic leukaemia. We assessed immunogenicity in the per-protocol cohort for immunogenicity and safety in the total vaccinated cohort. The study is registered with ClinicalTrials.gov, number NCT01767467, and with the EU Clinical Trials Register, number 2012-003438-18.

FINDINGS

Between March 1, 2013, and Sept 10, 2015, we randomly assigned 286 participants to adjuvanted recombinant zoster vaccine and 283 to placebo. 283 in the vaccine group and 279 in the placebo group were vaccinated. At month 2, 119 (80·4%, 95% CI 73·1-86·5) of 148 participants had a humoral vaccine response to adjuvanted recombinant zoster vaccine, compared with one (0·8%, 0·0-4·2) of 130 participants in the placebo group, and the adjusted geometric mean anti-glycoprotein E antibody concentration was 23 132·9 mIU/mL (95% CI 16 642·8-32 153·9) in the vaccine group and 777·6 mIU/mL (702·8-860·3) in the placebo group (adjusted geometric mean ratio 29·75, 21·09-41·96; p<0·0001) in all patients, excluding those with non-Hodgkin B-cell lymphoma and chronic lymphocytic leukaemia. Humoral and cell-mediated immune responses persisted above baseline until month 13 in all strata and, as expected, vaccine was more reactogenic than placebo (within 7 days after vaccination pain was reported by 221 [79·5%] of 278 vaccine group participants and 45 [16·4%] of 274 placebo group participants; fatigue was reported by 162 [58·3%] of 278 vaccine group participants and 102 [37·2%] of 274 placebo group participants). Incidences of unsolicited or serious adverse events, potential immune-mediated diseases, disease-related events, and fatal serious adverse events were similar between the groups.

INTERPRETATION

The immunocompromised adult population with haematological malignancies is at high risk for herpes zoster. The adjuvanted recombinant zoster vaccine, which is currently licensed in certain countries for adults aged 50 years and older, is likely to benefit this population.

FUNDING

GlaxoSmithKline Biologicals SA.

Immunogenicity and safety of the adjuvanted recombinant zoster vaccine in patients with solid tumors, vaccinated before or during chemotherapy: A randomized trial

BACKGROUND

The adjuvanted recombinant zoster vaccine (RZV) has demonstrated >90% efficacy against herpes zoster in adults ≥50 years of age and 68% efficacy in autologous hematopoietic stem cell transplant recipients ≥18 years of age. We report the immunogenicity and safety of RZV administered to patients with solid tumors (STs) before or at the start of a chemotherapy cycle.

METHOD

In this phase 2/3 observer-blind, multicenter study (NCT01798056), patients with STs who were ≥18 years of age were randomized (1:1) to receive 2 doses of RZV or placebo 1-2 months apart and stratified (4:1) according to the timing of the first dose with respect to the start of a chemotherapy cycle (first vaccination 8-30 days before the start or at the start [±1 day] of a chemotherapy cycle). Anti-glycoprotein E (gE) antibody concentrations, gE-specific CD4+ T cell frequencies, and vaccine response rates (VRRs) were assessed 1 month after dose 1 and 1 and 12 months after dose 2. Reactogenicity and safety were assessed in the total vaccinated cohort through 12 months after dose 2.

RESULTS

There were 232 participants in the total vaccinated cohort, 185 participants in the according-to-protocol cohort for humoral immunogenicity, and 58 participants in the according-to-protocol cohort for cell-mediated immunogenicity. Postvaccination anti-gE antibody concentrations, gE-specific CD4+ T cell frequencies and VRRs were higher in RZV recipients than in placebo recipients. Solicited adverse events (AEs) were more frequent among RZV recipients than placebo recipients. Incidence of unsolicited AEs, serious AEs, fatalities, and potential immune-mediated diseases were similar between RZV and placebo recipients.

CONCLUSION

RZV was immunogenic in patients with STs receiving immunosuppressive chemotherapies. Humoral and cell-mediated immune responses persisted 1 year after vaccination. No safety concerns were identified.

Vaccination of haemopoietic stem cell transplant recipients: guidelines of the 2017 European Conference on Infections in Leukaemia (ECIL 7)

Infection is a main concern after haemopoietic stem cell transplantation (HSCT) and a major cause of transplant-related mortality. Some of these infections are preventable by vaccination. Most HSCT recipients lose their immunity to various pathogens as soon as the first months after transplant, irrespective of the pre-transplant donor or recipient vaccinations. Vaccination with inactivated vaccines is safe after transplantation and is an effective way to reinstate protection from various pathogens (eg, influenza virus and Streptococcus pneumoniae), especially for pathogens whose risk of infection is increased by the transplant procedure. The response to vaccines in patients with transplants is usually lower than that in healthy individuals of the same age during the first months or years after transplant, but it improves over time to become close to normal 2-3 years after the procedure. However, because immunogenic vaccines have been found to induce a response in a substantial proportion of the patients as early as 3 months after transplant, we recommend to start crucial vaccinations with inactivated vaccines from 3 months after transplant, irrespectively of whether the patient has or has not developed graft-versus-host disease (GvHD) or received immunosuppressants. Patients with GvHD have higher risk of infection and are likely to benefit from vaccination. Another challenge is to provide HSCT recipients the same level of vaccine protection as healthy individuals of the same age in a given country. The use of live attenuated vaccines should be limited to specific situations because of the risk of vaccine-induced disease.

Respiratory Viral Infections in Patients With Cancer or Undergoing Hematopoietic Cell Transplant

Survival rates for pediatric cancer have steadily improved over time but it remains a significant cause of morbidity and mortality among children. Infections are a major complication of cancer and its treatment. Community acquired respiratory viral infections (CRV) in these patients increase morbidity, mortality and can lead to delay in chemotherapy. These are the result of infections with a heterogeneous group of viruses including RNA viruses, such as respiratory syncytial virus (RSV), influenza virus (IV), parainfluenza virus (PIV), metapneumovirus (HMPV), rhinovirus (RhV), and coronavirus (CoV). These infections maintain a similar seasonal pattern to those of immunocompetent patients. Clinical manifestations vary significantly depending on the type of virus and the type and degree of immunosuppression, ranging from asymptomatic or mild disease to rapidly progressive fatal pneumonia Infections in this population are characterized by a high rate of progression from upper to lower respiratory tract infection and prolonged viral shedding. Use of corticosteroids and immunosuppressive therapy are risk factors for severe disease. The clinical course is often difficult to predict, and clinical signs are unreliable. Accurate prognostic viral and immune markers, which have become part of the standard of care for systemic viral infections, are currently lacking; and management of CRV infections remains controversial. Defining effective prophylactic and therapeutic strategies is challenging, especially considering, the spectrum of immunocompromised patients, the variety of respiratory viruses, and the presence of other opportunistic infections and medical problems. Prevention remains one of the most important strategies against these viruses. Early diagnosis, supportive care and antivirals at an early stage, when available and indicated, have proven beneficial. However, with the exception of neuraminidase inhibitors for influenza infection, there are no accepted treatments. In high-risk patients, pre-emptive treatment with antivirals for upper respiratory tract infection (URTI) to decrease progression to LRTI is a common strategy. In the future, viral load and immune markers may prove beneficial in predicting severe disease, supporting decision making and monitor treatment in this population.

First International Precision Vaccines Conference: Multidisciplinary Approaches to Next-Generation Vaccines

Vaccines represent a remarkable success in the history of medicine since they have prevented and, in some instances, eradicated a range of infectious diseases. However, for many existing vaccines, immunogenicity is limited, requiring multiple booster doses, and we are still unable to target many pathogens due to intrinsic features of the microorganism, such as genetic/antigenic variability between strains, and our limited understanding of the variables that regulate vaccine responsiveness, including age- and sex-specific differences. Moreover, the traditional approach to vaccine development is often empirical, relying on inactivation of microorganisms or purification of their components, which are usually less immunogenic than the whole microorganism from which they derive. This approach has yielded multiple important vaccines but has failed to consistently generate vaccines that are sufficiently immunogenic in populations with limited immune responsiveness such as newborns and elderly individuals. In an effort to trigger impactful collaborations, a community of scientists gathered in Boston in the United States for the first biennial International Precision Vaccines Conference, sponsored by the Boston Children's Hospital Precision Vaccines Program, to discuss innovation in vaccinology. Recent advancements in the field of systems biology that can identify vaccine immunogenicity biomarkers for target populations, in human in vitro models, and in novel adjuvant and formulation strategies offer unprecedented opportunities to dissect the human immune response to vaccines and inform dramatic improvements in vaccine efficacy. These approaches are poised to have a major scientific and translational impact in vaccinology.

Design and characterisation of a dissolving microneedle patch for intradermal vaccination with heat-inactivated bacteria: A proof of concept study

This work describes the formulation and evaluation of dissolving microneedle patches (MNs) for intradermal delivery of heat-inactivated bacteria. Pseudomonas aeruginosa, strain PA01, was used as a model bacterium. Utilising a simple, cost effective fabrication process, P. aeruginosa was heat-inactivated and formulated into dissolving MNs, fabricated from aqueous blends of 20% w/w poly(methylvinylether/maleic acid). The resultant MNs were of sufficient mechanical strength to consistently penetrate a validated skin model Parafilm M®, inserting to a depth of between 254 and 381 µm. MNs were successfully inserted into murine skin and partially dissolved. Analysis of MN dissolution kinetics in murine ears via optical coherence tomography showed almost complete MN dissolution 5 min post-insertion. Mice were vaccinated using these optimised MNs by application of one MN to the dorsal surface of each ear (5 min). Mice were subsequently challenged intranasally (24 h) with a live culture of P. aeruginosa (2 × 10⁶ colony forming units). Bacterial load in the lungs of mice vaccinated with P. aeruginosa MNs was significantly (p = 0.0059) lower than those of their unvaccinated counterparts. This proof of concept work demonstrates the potential of dissolving MNs for intradermal vaccination with heat-inactivated bacteria. MNs may be a cost effective, potentially viable delivery system, which could easily be implemented in developing countries, allowing a rapid and simplified approach to vaccinating against a specific pathogen.

Neutralizing Anti-Hemagglutinin Monoclonal Antibodies Induced by Gene-Based Transfer Have Prophylactic and Therapeutic Effects on Influenza Virus Infection

Hemagglutinin (HA) of influenza virus is a major target for vaccines. HA initiates the internalization of the virus into the host cell by binding to host sialic acid receptors; therefore, inhibition of HA can significantly prevent influenza virus infection. However, the high diversity of HA permits the influenza virus to escape from host immunity. Moreover, the vaccine efficacy is poor in some high-risk populations (e.g., elderly or immunocompromised patients). Passive immunization with anti-HA monoclonal antibodies (mAbs) is an attractive therapy; however, this method has high production costs and requires repeated inoculations. To address these issues, several methods for long-term expression of mAb against influenza virus have been developed. Here, we provide an overview of methods using plasmid and viral adeno-associated virus (AAV) vectors that have been modified for higher expression of neutralizing antibodies in the host. We also examine two methods of injection, electro-transfer and hydrodynamic injection. Our results show that antibody gene transfer is effective against influenza virus infection even in immunocompromised mice, and antibody expression was detected in the serum and upper respiratory tract. We also demonstrate this method to be effective following influenza virus infection. Finally, we discuss the perspective of passive immunization with antibody gene transfer for future clinical trials.

Validation of γ-radiation and ultraviolet as a new inactivators for foot and mouth disease virus in comparison with the traditional methods

AIM

The present work deals with different methods for foot and mouth disease virus (FMDV) inactivation for serotypes O/pan Asia, A/Iran05, and SAT-2/2012 by heat, gamma radiation, and ultraviolet (UV) in comparison with the traditional methods and their effects on the antigenicity of viruses for production of inactivated vaccines.

MATERIALS AND METHODS

FMDV types O/pan Asia, A/Iran05, and SAT-2/2012 were propagated in baby hamster kidney 21 (BHK21) and titrated then divided into five parts; the first part inactivated with heat, the second part inactivated with gamma radiation, the third part inactivated with UV light, the fourth part inactivated with binary ethylamine, and the last part inactivated with combination of binary ethylamine and formaldehyde (BEI+FA). Evaluate the method of inactivation via inoculation in BHK21, inoculation in suckling baby mice and complement fixation test then formulate vaccine using different methods of inactivation then applying the quality control tests to evaluate each formulated vaccine.

RESULTS

The effect of heat, gamma radiation, and UV on the ability of replication of FMDV "O/pan Asia, A/Iran05, and SAT-2/2012" was determined through BHK cell line passage. Each of the 9 virus aliquots titer 10(8) TCID50 (3 for each strain) were exposed to 37, 57, and 77°C for 15, 30, and 45 min. Similarly, another 15 aliquots (5 for each strain) contain 1 mm depth of the exposed samples in petri-dish was exposed to UV light (252.7 nm wavelength: One foot distance) for 15, 30, 45, 60, and 65 min. Different doses of gamma radiation (10, 20, 25, 30, 35, 40, 45, 50, 55, and 60 KGy) were applied in a dose rate 0.551 Gy/s for each strain and repeated 6 times for each dose. FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) were inactivated when exposed to heat ≥57°C for 15 min. The UV inactivation of FMDV (O/pan Asia and SAT-2) was obtained within 60 min and 65 min for type A/Iran05. The ideal dose for inactivation of FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) with gamma radiation were 55-60 and 45 kGy, respectively. Inactivation of FMDV with binary was 20, 24 and 16 hr for O/pan Asia, A/Iran05, and SAT-2/2012, respectively while inactivation by (BEI+FA) was determined after 18, 19 and 11 hr for O/pan-Asia, A/Iran 05, and SAT-2/2012, respectively. The antigenicity of control virus before inactivation was 1/32, it was not changed after inactivation in case of gamma radiation and (BEI+FA) and slightly decrease to 1/16 in case of binary and declined to 1/2, 1/4 in case of heat and UV inactivation, respectively. The immune response induced by inactivated FMD vaccines by gamma radiation and (BEI+FA) lasted to 9 months post-vaccination, while the binary only still up to 8 months post-vaccination but heat and UV-inactivated vaccines were not effective.

CONCLUSION

Gamma radiation could be considered a good new inactivator inducing the same results of inactivated vaccine by binary with formaldehyde (BEI+FA).

Impact of host genetic polymorphisms on vaccine induced antibody response

Many host- and vaccine-specific factors modulate an antibody response. Host genetic polymorphisms, in particular, modulate the immune response in multiple ways on different scales. This review article describes how information on host genetic polymorphisms and corresponding immune cascades may be used to generate personalized vaccine strategies to optimize the antibody response.

New insights on the development of fungal vaccines: from immunity to recent challenges

Fungal infections are emerging as a major problem in part due to high mortality associated with systemic infections, especially in the case of immunocompromised patients. With the development of new treatments for diseases such as cancer and the acquired immune deficiency syndrome pandemic, the number of immunosuppressed patients has increased and, as a consequence, also the number of invasive fungal infections has increased. Several studies have proposed new strategies for the development of effective fungal vaccines. In addition, better understanding of how the immune system works against fungal pathogens has improved the further development of these new vaccination strategies. As a result, some fungal vaccines have advanced through clinical trials. However, there are still many challenges that prevent the clinical development of fungal vaccines that can efficiently immunise subjects at risk of developing invasive fungal infections. In this review, we will discuss these new vaccination strategies and the challenges that they present. In the future with proper investments, fungal vaccines may soon become a reality.

Practical review of immunizations in adult patients with cancer

Compared with the general population, patients with cancer in general are more susceptible to vaccine-preventable infections, either by an increased risk due to the malignancy itself or immunosuppressive treatment. The goal of immunizations in these patients is therefore to provide protection against these infections, and to decrease the number of vulnerable patients who can disseminate these organisms. The proper timing of immunization with cancer treatment is key to achieving better vaccine protection. As the oncology field continues to advance, leading to better quality of life and longer survival, immunization and other aspects of preventive medicine ought to move to the frontline in the care of these patients. Herein, we review the vaccines most clinically relevant to patients with cancer, as well as special cases including vaccines after splenectomy, travel immunization and recommendations for family members.

Lower response to early T-cell-dependent vaccination after neurotrauma or neurosurgery in adults

BACKGROUND

Recent international guidelines recommend vaccination with a 13-valent pneumococcal conjugate vaccine to reduce the risk of meningitis after neurotrauma with cerebrospinal fluid leak. The antibody response and optimal time point for vaccination have not been established and because the risk of meningitis is at the highest shortly after trauma, early vaccination is preferable. This study aimed to investigate the antibody response and to ensure that central nervous system injury-induced immunodepression did not affect the response to a T-cell-dependent conjugate vaccine when administered shortly after the injury.

METHODS

So as not to interfere with routine pneumococcal vaccination, a conjugate vaccine against Haemophilus influenza type b (Hib) was chosen for the study. Thirty-three patients with basilar skull fracture and 23 patients undergoing transsphenoidal pituitary gland surgery were vaccinated within 10 days after trauma/surgery and 29 control patients at least three weeks after trauma/surgery. Sera were collected pre- and post-vaccination for analysis of anti-Hib concentration.

RESULTS

Four patients with post-vaccination target antibody concentration before vaccination were excluded from analysis. In the neurotrauma and neurosurgery groups 10/32 (31%) and 5/20 (25%) patients, respectively, were non-responders compared with 3/29 (10%) in the control group. Log10 anti-Hib concentrations in the neurotrauma, neurosurgery and control groups were 1.52 ± 0.15, 1.38 ± 0.15 and 1.81 ± 0.12 μg/ml, respectively.

CONCLUSIONS

The majority of the patients responded to vaccination. However, the number of responders was significantly decreased and antibody concentration significantly lower in patients vaccinated early after the trauma/surgery. Investigation of the pneumococcal conjugate vaccine response in neurotrauma patients is therefore urgent.

Inactivated Viral Vaccines

Inactivated vaccines have been used for over a century to induce protection against viral pathogens. This established approach of vaccine production is relatively straightforward to achieve and there is an augmented safety profile as compared to their live counterparts. Today, there are six viral pathogens for which licensed inactivated vaccines are available with many more in development. Here, we describe the principles of viral inactivation and the application of these principles to vaccine development. Specifically emphasized are the manufacturing procedure and the accompanying assays, of which assays used for monitoring the inactivation process and preservation of neutralizing epitopes, are pivotal. Novel inactivated vaccines in development and the hurdles they face for licensure are also discussed as well as the (dis)advantages of inactivation over the other vaccine production methodologies.