Safety and Efficacy of Single-Dose Ad26.COV2.S Vaccine against Covid-19

Lessons for medical countermeasure development from unforeseen outbreaks

The unanticipated emergence of the COVID-19 pandemic and the rapid spread of the mpox epidemic in 2022 and 2024 brought unforeseen challenges to public health. While distinct in nature, these outbreaks share some similarities and offer valuable insights into responding to novel virus dissemination in vulnerable populations. In light of these two experiences, we aim to discern the prioritization of medical countermeasures (MCM) among antivirals, antibodies, and vaccines. Comparative analysis of MCMs reveals that while antivirals serve essential roles as therapeutic tools, monoclonal antibodies can be used for both prevention and treatment, and vaccines remain of paramount importance for controlling epidemics as mass or targeted prophylaxis. Variability in production processes, administration methods, logistics, and costs distinguish these countermeasures. Vaccines, by inducing long-lasting immunity and ideally promoting herd effects, exhibit substantial advantages over other options. To enhance future pandemic readiness, proactive measures must include ready-to-use vaccine platforms with regulatory approval and manufacturing capacities, as well as prototype vaccines for representative pathogens and preexisting protocols to evaluate their efficacies and side effects. The comparison underscores the challenges of social acceptance and equity, particularly in vaccine production and distribution. As the world faces unknown agents, the three major types of MCMs do not have equal and symmetrical effects in terms of epidemic control. Thus, a vaccine-oriented strategy with a community-centered approach, proves essential for effective pandemic preparedness, encouraging continued innovation in vaccinology.

Limitations of neutralizing antibody titers in COVID-19 vaccine efficacy trials and a call for additional correlates of protection

The coronavirus disease (COVID-19) pandemic accelerated development of various vaccine platforms. Among them, mRNA vaccines played a crucial role in controlling the pandemic due to their swift development and efficacy against virus variants. Despite the success of these vaccines, recent studies highlight challenges in evaluating vaccine efficacy, especially in individuals with prior COVID-19 infection. Weakened neutralizing antibody responses after additional doses are observed in these populations, raising concerns about using neutralizing antibody titers as the sole immune correlate of protection. While neutralizing antibodies remain the primary endpoint in immunogenicity trials, they may not fully capture the immune response in populations with widespread prior infection or vaccination. This review explores reduced neutralizing antibody responses in previously infected individuals, and their impact on vaccine efficacy evaluation. It also offers recommendations for improving efficacy assessment, stressing incorporation of additional immune markers such as cell-mediated immunity to enable more comprehensive understanding of vaccine-induced immunity.

Disparities in COVID-19 Vaccine Uptake Among Pregnant People in a Diverse Urban Population With High Vaccine Acceptance

Introduction

This study's objective was to compare COVID-19 vaccination rates between pregnant individuals in San Francisco and the city's similarly aged population and to identify the factors associated with vaccine uptake in the pregnant population.

Methods

This was a retrospective cohort study of all patients delivering at 2 hospitals in San Francisco from March 15, 2021, to October 15, 2021. Reference COVID-19 vaccination rates for San Francisco were obtained from the California Immunization Registry. The primary outcome was completion of a COVID-19 vaccine series among pregnant individuals compared with that in the San Francisco general population aged 18-45 years. Secondary outcomes included factors associated with COVID-19 vaccination among pregnant people.

Results

Of 2,294 pregnant individuals, 1,181 (51.5%) completed a COVID-19 vaccine series by delivery. Pregnant individuals were less likely to be vaccinated than the San Francisco population throughout the study period. Factors associated with lower vaccination rates in pregnant individuals included public insurance (AOR=0.21, 95% CI=0.16, 0.27), younger age (AOR=0.74, 95% CI=0.64, 0.86), English language preference (AOR=0.58, 95% CI=0.42, 0.80), and self-identified Black (AOR=0.26, 95% CI=0.17, 0.40) (ref: White), Hispanic (AOR=0.61, 95% CI=0.46, 0.81), or other (AOR=0.50, 95% CI=0.36, 0.68) race or ethnicity.

Conclusions

COVID-19 vaccination coverage among pregnant people in San Francisco lagged behind that of the city's similarly aged population, particularly among those with public insurance and of non-White race. Despite locally high vaccine acceptance, additional efforts are needed to address barriers and reduce disparities in COVID-19 vaccination within the pregnant population.

Testing an experimental vaccine during a public health emergency: Lessons from a Peruvian case

INTRODUCTION

The Peruvian Government searched for a vaccine as a response to COVID-19. A clinical trial evaluating an inactivated SARS-CoV-2 vaccine was approved. A national news program revealed that Peru's president had received the vaccine outside the clinical trial, generating a national protest. The Peruvian National Academy of Medicine created a commission to identify improper procedures and provide guidance on how to prevent a similar case in the future.

METHODS

Commission members reviewed all publicly available documents and information sources and generated a final report.

RESULTS

There were 6 ethical principles violations: 1) 3200 vaccine doses were used to vaccinate individuals outside the clinical trial; 2) prominent individuals were vaccinated outside of the clinical trial; 3) study conduct was monitored by a contract research organization with a conflict of interest; 4) an additional study was conducted with the vaccine without an approved protocol; 5) the placebo-controlled trial was continued when an approved vaccine was available; and 6) results of the clinical trial were not released. There were 5 regulatory procedures ignored: 1) no clinical trial supervision by a high-quality clinical monitoring agency outside Peru; 2) a university acting as a sponsor of a vaccine produced by a foreign company; 3) expedited reviews and approvals; 4) lack of adequate supervision by local regulatory bodies and the study contract research organization (CRO); and 5) no input from the Data Safety Monitoring Board.

CONCLUSIONS

The COVID-19 health emergency created an environment where existing regulatory and ethical principles were circumvented under political pressure. Regulatory bodies and agencies should inform countries of the dangers of conducting clinical trials during a public health emergency and proper ethical and regulatory procedures should be followed.

A novel, covalent broad-spectrum inhibitor targeting human coronavirus Mpro

Human coronaviruses (CoV) cause respiratory infections that range from mild to severe. CoVs are a large family of viruses with considerable genetic heterogeneity and a multitude of viral types, making preventing and treating these viruses difficult. Comprehensive treatments that inhibit CoV infections fulfill a pressing medical need and may be immensely valuable in managing emerging and endemic CoV infections. As the main protease (Mpro) is highly conserved across many CoVs, this protease has been identified as a route for broad CoV inhibition. We utilize the advanced generative chemistry platform Chemistry42 for de novo molecular design and obtained novel small-molecule, non-peptide-like inhibitors targeting the SARS-CoV-2 Mpro. ISM3312 is identified as an irreversible, covalent Mpro inhibitor from extensive virtual screening and structure-based optimization efforts. ISM3312 exhibits low off-target risk and outstanding antiviral activity against multiple human coronaviruses, including SARS-CoV-2, MERS-CoV, 229E, OC43, NL63, and HKU1 independent of P-glycoprotein (P-gp) inhibition. Furthermore, ISM3312 shows significant inhibitory effects against Nirmatrelvir-resistant Mpro mutants, suggesting ISM3312 may contribute to reduced viral escape in these settings. Incorporating ISM3312 and Nirmatrelvir into antiviral strategy could improve preparedness and reinforce defenses against future coronavirus threats.

A modular mRNA vaccine platform encoding antigen-presenting capsid virus-like particles enhances the immunogenicity of the malaria antigen Pfs25

The COVID-19 pandemic has emphasized the potential of mRNA vaccines in fighting pandemics, owing to their rapid development, strong immunogenicity and adaptability. However, a drawback is their dose-limiting reactogenicity and inability to generate durable humoral immunity. Here we introduce a modular nucleotide vaccine platform combining the advantages of genetic and capsid virus-like-particle-based vaccines. This platform allows for the display of various antigens on different capsid virus-like particles, improving the magnitude, quality and longevity of the vaccine-induced immune responses. We applied this technology to enhance the immunogenicity of the Pfs25 antigen. Immunization with lipid-nanoparticle-formulated mRNA encoding Pfs25 capsid virus-like particles resulted in higher and potentially more durable anti-Pfs25 antibody responses, along with enhanced functional activity, compared with an mRNA vaccine encoding soluble Pfs25. By improving both humoral and cellular immune responses, this approach may reduce the dose and number of administrations required for effective protection. As a result, it can improve the feasibility of both DNA- and mRNA-based vaccines targeting pandemic and endemic infectious diseases.

Effectiveness of interventions to improve vaccine efficacy: a systematic review and meta-analysis

BACKGROUND

Vaccination is a crucial public health intervention that has significantly reduced the incidence of infectious diseases. Vaccine-related interventions refer to strategies implemented to enhance vaccination uptake, coverage, and effectiveness, like modes of delivery, types or dosages. Despite extensive research on vaccine efficacy, a comprehensive analysis of the variability in vaccine effectiveness across different interventions, settings, and populations is limited. This study aims to systematically review and meta-analyze the impact of various Vaccine-Related Interventions (VRIs).

METHODS

This review included 139 randomized controlled trials, cohort, and case-control studies evaluating VRIs from January 2015 to December 2023. The risk of bias was assessed using the ROB-2 and ROBINS-E tools. Statistical analyses were conducted to evaluate overall effect sizes, infection rates, and heterogeneity and subgroup analysis.

RESULTS

Of the 139 studies reviewed, 97 were included in the meta-analysis, comprising approximately 1.4 million participants. Populations across various settings were analyzed, with median vaccinated population sizes for the 1st dose (4598, IQR = 15,749), 2nd dose (6214, IQR = 13,817), and 3rd dose (3508, IQR = 5546). The overall total vaccinated population had a median of 4370 and an IQR of 16,475. The interventions showed a significant positive effect on vaccine efficacy, with an estimated effect size of 0.6432 (95% CI 0.4049 to 0.8815). Heterogeneity was negligible, with Tau2 = 0, I2 = 0.00%, and H2 = 1.00. The Galbraith plot suggested minimal variability. The study utilized ROB-2 and ROBINS-E tools to evaluate bias, with Egger's test (t = - 0.9941, p = 0.3227) confirming no significant publication bias. The funnel plot indicated minimal bias in the included studies.

CONCLUSION

The study supports the effectiveness of vaccine-related interventions in enhancing vaccine efficacy. The negligible heterogeneity and consistent effect sizes across diverse populations and settings provide a robust basis for implementing public health strategies aimed at improving vaccination outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024543608.

Delayed but successful development of immune memory against SARS-COV-2 after B cell-depleting monotherapy

PURPOSE

Patients receiving CD20-directed therapies are known to insufficiently develop neutralizing antibody titers against SARS-COV-2 after two vaccinations. We investigated the impact of a third and fourth vaccination, possibly deriving predictive factors.

METHODS

In a monocentric, prospective, non-interventional observational study patients who had received at least one administration of a monoclonal CD20 antibody (mCD20Ab) within 9 months prior to vaccination were included to receive mRNA-based third vaccination. SARS-COV-2 IgG titer was determined before and four weeks after immunisation. Patients without adequate humoral immune response proceeded to a fourth vaccination. Furthermore, tolerability and prespecified potentially influencing factors such as age, baseline lymphocyte counts and others were analysed.

RESULTS

Twenty-four patients were included and vaccination was well tolerated. Quantitative analysis of humoral response four weeks after third vaccination revealed a significant increase which, however, did not translate into a clinically relevant seroconversion rate. In the subgroup analysis, patients older than 65 years and mCD20Ab therapy longer than 6 months ago benefited. All evaluable patients on mCD20Ab monotherapy (n = 7) showed an immediate or delayed immune response after third vaccination, while all non-responders (n = 7) were on combination therapy. Clinical parameters such as lymphocyte count, immunoglobulin status and others did not appear to have any influence.

CONCLUSION

An interval of at least 6 months after the last mCD20Ab administration and mCD20Ab monotherapy appears to be favorable for humoral immune response to third vaccination. Furthermore, patients can be reassured that delayed immune responses are possible. Future studies should therefore also investigate seroconversion at later time points.

Effectiveness over time of a primary series of the original monovalent COVID-19 vaccines in adults in the United States

With data from 2 US claims databases (Optum, CVS Health) supplemented with Immunization Information System COVID-19 vaccine records, we evaluated overall and time-specific vaccine effectiveness (VE) of an initial primary series for 3 monovalent COVID-19 vaccines-BNT162b2, mRNA-1273, and JNJ-7836735-in adults (18-64 years). Vaccinated individuals were matched to unvaccinated comparators, and we estimated VE against any medically diagnosed COVID-19 and hospital/emergency department (ED)-diagnosed COVID-19. Additionally, we estimated VE by era of predominant variants, in subgroups, and compared across vaccine brands. The cohorts consisted of 341,097 (Optum) and 1,151,775 (CVS Health) matched pairs for BNT162b2; 201,604 (Optum) and 651,545 (CVS Health) for mRNA-1273; and 49,285 (Optum) and 149,813 (CVS Health) for JNJ-7836735. The study period began 11 December 2020 (date of first COVID-19 vaccine availability in the US) and ended 15 January 2022 in Optum and 31 March 2022 in CVS Health. Summary VE estimates from meta-analysis against hospital/ED-diagnosed COVID-19 were: BNT162b2, 77% (95% CI, 76%-78%); mRNA-1273, 84% (95% CI, 83%-85%), JNJ-7836735 66% (95% CI, 63%-68%). VE estimates were higher for hospital/ED-diagnosed COVID-19 than for medically diagnosed COVID-19, and VE estimates were highest in adults receiving mRNA-1273 for both outcomes. VE was sustained for approximately 7 months for medically diagnosed and up to 9 months for hospital/ED-diagnosed COVID-19. VE differed by brand and variant era. Ongoing real-world surveillance of COVID-19 vaccines using robust data sources and methodology is needed as new variants and recommendations for updated vaccines have evolved.

A Self-Assembled Nanovaccine with BA.4/5 Receptor-Binding Domain and CpG Oligodeoxynucleotides Induces Broad-Spectrum Neutralization against SARS-CoV-2 Omicron Subvariants

Over the past 3 years, SARS-CoV-2 Omicron has been circulating globally with the emergence of multiple subvariants, including BA.5, BA.5.2, XBB, XBB.1, EG.5.1, HK.3, BA.2.86, JN.1, and KP.2. To combat these Omicron subvariants, several vaccines based on receptor-binding domain (RBD) dimers have been developed; however, RBD dimer vaccines require frequent updates to cope with the emergence of new variants. In contrast, the development of a safe, effective, and broad-spectrum vaccine against multiple Omicron subvariants, including the latest JN.1 and KP.2, would be a one-size-fits-all solution. Here, we designed BA.4/5 RBD-PC7A conjugate micelles by displaying the BA.4/5 RBD in PC7A micelles. Remarkably, the micelles elicited potent neutralizing antibodies (NAbs) in rabbits, effectively neutralizing BA.5.2, XBB.1.18, and HK.3 infections. Moreover, the micelles alone were able to induce NAbs in mice against the BA.5 variant. When a cytosine-phosphate-guanine (CpG) adjuvant was added and electrostatically adsorbed to the micelles, there was a significant increase in the antibody titers of IgG1, IgG2b, and IgG2c. This enhancement facilitated the broad neutralization of various strains, including BA.5.2, XBB.1.18, HK.3, JN.1, and KP.2. Furthermore, the micelles adsorbed with CpG protected golden hamsters from infection with the BA.5.2 strain. This study presents a potent and broadly neutralizing nanovaccine that includes the BA.4/5 RBD antigen and a CpG adjuvant. It demonstrates efficacy against multiple Omicron subvariants, including BA.5, BA.5.2, XBB.1.18, HK.3, JN.1, and KP.2, highlighting its potential for clinical translation.

Elicitation of liver-stage immunity by nanoparticle immunogens displaying P. falciparum CSP-derived antigens

A vaccine that provides robust, durable protection against malaria remains a global health priority. Although a breakthrough in the fight against malaria has recently been achieved by the licensure of two vaccines based on the circumsporozoite protein (CSP), the effectiveness and durability of protection can still be improved. Both vaccines contain a portion of CSP that does not include epitopes targeted by recently identified, potently protective monoclonal antibodies, suggesting that newer immunogens can expand the breadth of immunity and potentially increase protection. Here we explored >100 alternative CSP-based immunogens and evaluated the immunogenicity and protection of a large number of candidates, comparing several to the licensed R21 vaccine. The data highlight several general features that improve the stability and immunogenicity of CSP-based vaccines, such as inclusion of the C-terminal domain and high-density display on protein nanoparticle scaffolds. We also identify antigen design strategies that do not warrant further exploration, such as synthetic repeat regions that include non-native repeat cadences. The benchmark R21 vaccine outperformed our best immunogen for immunogenicity and protection. Overall, our data provide valuable insights on the inclusion of junctional region epitopes that will guide the development of potent and durable vaccines against malaria.

Viral agents in neuromuscular pathology

In recent years, viral infections have been increasingly identified as major players in neuromuscular pathologies. This chapter presents an overview of the evidence and future directions for virus-induced neuromuscular disorders. Information is integrated on the global burden of these diseases related to epidemiology, clinical features, diagnosis, treatment, and preventive strategies was integrated. Responsible viruses include enteroviruses, flaviviruses, herpesviruses, and emerging pathogens such as SARS-CoV-2. It represents a broad spectrum of neuromuscular disorders, including Guillain-Barré syndrome, viral myositis, and critical illness neuropathy/myopathy. The book chapter discusses different diagnostic approaches, therapy strategies, and rehabilitation methods, in addition to early intervention and preventive measures. This has led to new insights into novel therapies, unmet research needs, and future perspectives on viral neuromuscular disorders. This chapter demonstrates that supporting both clinical care and patient management with clinical research entails a profound understanding of the difficult interactions between the viruses concerned and the neuromuscular system.

Immunologic Response and Effects of COVID-19 Vaccines in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

PURPOSE

The immunological response and adverse effects of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) in patients receiving coronavirus disease-2019 (COVID-19) vaccines remain unclear. We aimed to evaluate the effects of these vaccines on AAV disease activity.

MATERIALS AND METHODS

We reviewed the medical records of 52 patients with AAV who had received at least second doses of the COVID-19 vaccine and evaluated their immunogenicity by measuring the anti-spike (S) antibody (Ab) titer levels using the Roche Elecsys® immunoassay. Responses to the Birmingham Vasculitis Activity Score (BVAS) tool and 36-Item Short Form Survey before and after vaccination were obtained to assess AAV disease activity. Vaccine reactivity was measured using a standardized questionnaire.

RESULTS

We enrolled 52 patients with AAV. No differences were found between those who received second and third doses of vaccination in terms of AAV type, disease activity, vaccine type, or the use of immunosuppressive agents, including steroids. The median anti-S Ab titer was 3967.0 after third doses compared to 419.0 after second doses (p=0.001). Except for mycophenolate mofetil (MMF), when immunosuppressants were administered in conjunction with steroids, the Ab titer was higher after the third vaccination than that after the second dose. The BVAS remained unchanged before and after second and third doses. No life-threatening adverse events were reported.

CONCLUSION

Although COVID-19 vaccine may not produce sufficient antibodies in patients taking MMF, the vaccine did not exacerbate disease activity or cause severe side effects. Therefore, COVID-19 vaccines should be considered in patients with AAV.

Cryo-ET unravels the mystery of Ad5-nCoV vaccines

The Ad5-nCoV vaccine (Convidecia) against COVID-19 showed promising clinical results. However, the molecular mechanisms underlying its high immunogenicity and potential adverse reactions have remained elusive. In this issue of Structure, Dong et al.1 employed cryo-electron tomography as a powerful technique to show that abundant prefusion spike protein formation is induced by Ad5-nCoV vaccines.

Advancing ORFV-Based Therapeutics to the Clinical Stage

The Orf virus (ORFV) is the prototype member of the parapoxvirus family and has long been recognized for its robust immunogenicity, favourable safety profile and its ability to stimulate both cellular and humoural immune responses without inducing significant anti-vector immunity. Despite these inherent advantages, early applications of ORFV-based technologies were limited by challenges in manufacturing scalability and uncertainties regarding clinical safety in humans. However, recent breakthroughs have transformed this therapeutic landscape. A landmark achievement is the development of Prime-2-CoV, an ORFV-based anti-COVID-19 vaccine that has advanced into human clinical trials, providing the first clinical evidence of live ORFV's feasibility, safety and immunogenicity. This milestone, together with the establishment of a good manufacturing practice (GMP)-compliant production process and comprehensive preclinical evaluations, has laid a robust foundation for broader clinical applications of ORFV-based therapeutics. Moreover, the use of ORFV as an oncolytic virus therapy has shown promising results, effectively converting immunologically 'cold' tumours into 'hot' ones, underscoring its versatility as a therapeutic platform. In this review, we critically assess recent advances in ORFV-based therapeutics, with a particular focus on vaccine development and oncolytic virotherapy (OVT). We thoroughly discuss the milestones and impact of the first ORFV-based clinical trial, outline strategies for optimizing the technology and provide insights into overcoming remaining challenges. Collectively, these advancements position ORFV as a highly promising and versatile platform for next-generation prophylactic and therapeutic interventions in both human and veterinary medicine, while also providing a roadmap for future innovations.

Virus and cell specific HMGB1 secretion and subepithelial infiltrate formation in adenovirus keratitis

A highly contagious infection caused by human adenovirus species D (HAdV-D), epidemic keratoconjunctivitis (EKC) results in corneal subepithelial infiltration (SEI) by leukocytes, the hallmark of the infection. To date, the pathogenesis of corneal SEI formation in EKC is unresolved. HMGB1 (high-mobility group box 1 protein) is an alarmin expressed in response to infection and a marker of sepsis. Earlier studies using a different adenovirus species, HAdV-C, showed retention of HMGB1 in the infected cell nucleus by adenovirus protein VII, enabling immune evasion. Here, using HAdV-D we show cell-specific HMGB1 secretion by infected cells, and provide an HAdV-D specific mechanism for SEI formation in EKC. HMGB1 was secreted only upon infection of human corneal epithelial cells, not from other cell types, and only upon infection by HAdV-D types associated with EKC. Acetylated HMGB1 translocation from the nucleus to the cytoplasm, then to the extracellular milieu, was tightly controlled by CRM1 and LAMP1, respectively. Primary stromal cells when stimulated by rHMGB1 expressed proinflammatory chemokines. In a novel 3D culture system in tune with the architecture of the cornea, HMGB1 released by infected corneal epithelial cells induced leukocytic infiltrates either directly and/or indirectly via stimulated stromal cells, which together explains SEI formation in EKC.

Molecular basis of Ad5-nCoV vaccine-induced immunogenicity

Ad5-nCoV (Convidecia) is listed for emergency use against COVID-19 by the World Health Organization (WHO) and has been globally administered to millions of people. It utilizes human adenovirus 5 (Ad5) replication-incompetent vector to deliver the spike (S) protein gene from various SARS-CoV-2 strains. Despite promising clinical data, the molecular mechanism underlying its high immunogenicity and adverse reactions remain incompletely understood. Here, we primarily applied cryo-electron tomography (cryo-ET), fluorescence microscopy and mass spectrometry to analyze the Ad5-nCoV_Wu and Ad5-nCoV_O vaccine-induced S antigens. These antigens encode the unmodified SARS-CoV-2 Wuhan-Hu-1 S gene and the stabilized Omicron S gene, respectively. Our findings highlight the structural integrity, antigenicity, and dense distribution on cell membrane of the vaccine-induced S proteins. Ad5-nCoV_O induced S proteins exhibit improved stability and reduced syncytia formation among inoculated cells. Our work demonstrates that Ad5-nCoV is a prominent platform for antigen induction and cryo-ET can be a useful technique for vaccine characterization and development.

Vaccine effectiveness of JCOVDEN single-dose against COVID-19 hospitalisation in Europe: An id.DRIVE test-negative case-control study

BACKGROUND

JCOVDEN (Ad26.COV2.S), a viral-vector vaccine, was granted conditional marketing authorisation in the European Union for the prevention of COVID-19 in early 2021. We present JCOVDEN single-dose vaccine effectiveness (VE) estimates against COVID-19 hospitalisation.

METHODS

The id.DRIVE (previously COVIDRIVE) COVID-19 VE study is an ongoing European non-interventional, multi-centre study with a test-negative case-control design. Study participants were adults ≥ 18 years old, hospitalised with severe acute respiratory infection between 1 May 2021 and 28 February 2023. Estimated as a single measure over the entire study period, VE was stratified by risk group, time since vaccination intervals (14 days-12 weeks, 12-to-25 weeks, 25-to-52 weeks, >52 weeks), SARS-CoV-2 variant and calendar time categories. All estimates were adjusted for symptom-onset date, age, sex, and number of pre-defined chronic conditions.

RESULTS

Overall, VE was 55.6 % (95 % CI 23.6; 74.2) for a median time since vaccination of 146 days. For 18- to 49-year-olds, VE was 61.6 % (95 % CI 16.2; 82.4), 57.7 % (95 % CI 3.4; 81.5) for 50- to-64-years-olds, and 40.8 % (95 % CI -6.0; 66.9) for ≥ 65-year-olds. Most precise estimates were obtained for time since vaccination 12-to- 25-week interval (59.2 % [95 % CI 25.0; 77.8]) and for the calendar time period 1 Aug 2021 -30 Nov 2021 (Delta predominant; 51.2 % [95 % CI 21.7; 69.6]).

CONCLUSION

The JCOVDEN single-dose protected against COVID-19 hospitalisation. It is effective for at least six months, with VE estimates comparatively lower in the older age groups. Results had low to medium levels of certainty and are to be interpreted with caution.

Early effectiveness of the BNT162b2 KP.2 vaccine against COVID-19 in the US Veterans Affairs Healthcare System

This test-negative case-control study within the US Veterans Affairs Healthcare System aims to estimate early vaccine effectiveness (VE) of the BNT162b2 KP.2 vaccine (2024-2025 formulation) compared to not receiving the KP.2 vaccine against COVID-19 outcomes. The study includes adult patients (age ≥18 years) with an acute respiratory infection (ARI) in hospital, emergency department and urgent care (ED/UC), or outpatient settings between September 5 and November 30, 2024. Separate multivariable logistic regression models compare the odds of receiving BNT162b2 KP.2 vaccine among SARS-CoV-2 positive cases and test-negative controls within each ARI outcome category, while adjusting for potentially confounding variables. Among 44,598 ARI episodes, VE is 68% (42-82%), 57% (46-65%), and 56% (36-69%) against COVID-19-associated hospitalizations, emergency department and urgent care visits, and outpatient visits, respectively. Uptake of updated COVID-19 vaccines is low (3.7%).

Spike protein-related proteinopathies: A focus on the neurological side of spikeopathies

BACKGROUND

The spike protein (SP) is an outward-projecting transmembrane glycoprotein on viral surfaces. SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), responsible for COVID-19 (Coronavirus Disease 2019), uses SP to infect cells that express angiotensin converting enzyme 2 (ACE2) on their membrane. Remarkably, SP has the ability to cross the blood-brain barrier (BBB) into the brain and cause cerebral damage through various pathomechanisms. To combat the COVID-19 pandemic, novel gene-based products have been used worldwide to induce human body cells to produce SP to stimulate the immune system. This artificial SP also has a harmful effect on the human nervous system.

STUDY DESIGN

Narrative review.

OBJECTIVE

This narrative review presents the crucial role of SP in neurological complaints after SARS-CoV-2 infection, but also of SP derived from novel gene-based anti-SARS-CoV-2 products (ASP).

METHODS

Literature searches using broad terms such as "SARS-CoV-2", "spike protein", "COVID-19", "COVID-19 pandemic", "vaccines", "COVID-19 vaccines", "post-vaccination syndrome", "post-COVID-19 vaccination syndrome" and "proteinopathy" were performed using PubMed. Google Scholar was used to search for topic-specific full-text keywords.

CONCLUSIONS

The toxic properties of SP presented in this review provide a good explanation for many of the neurological symptoms following SARS-CoV-2 infection and after injection of SP-producing ASP. Both SP entities (from infection and injection) interfere, among others, with ACE2 and act on different cells, tissues and organs. Both SPs are able to cross the BBB and can trigger acute and chronic neurological complaints. Such SP-associated pathologies (spikeopathies) are further neurological proteinopathies with thrombogenic, neurotoxic, neuroinflammatory and neurodegenerative potential for the human nervous system, particularly the central nervous system. The potential neurotoxicity of SP from ASP needs to be critically examined, as ASPs have been administered to millions of people worldwide.

Beyond the Pandemic Era: Recent Advances and Efficacy of SARS-CoV-2 Vaccines Against Emerging Variants of Concern

Vaccination has been instrumental in curbing the transmission of SARS-CoV-2 and mitigating the severity of clinical manifestations associated with COVID-19. Numerous COVID-19 vaccines have been developed to this effect, including BioNTech-Pfizer and Moderna's mRNA vaccines, as well as adenovirus vector-based vaccines such as Oxford-AstraZeneca. However, the emergence of new variants and subvariants of SARS-CoV-2, characterized by enhanced transmissibility and immune evasion, poses significant challenges to the efficacy of current vaccination strategies. In this review, we aim to comprehensively outline the landscape of emerging SARS-CoV-2 variants of concern (VOCs) and sub-lineages that have recently surfaced in the post-pandemic years. We assess the effectiveness of existing vaccines, including their booster doses, against these emerging variants and subvariants, such as BA.2-derived sub-lineages, XBB sub-lineages, and BA.2.86 (Pirola). Furthermore, we discuss the latest advancements in vaccine technology, including multivalent and pan-coronavirus approaches, along with the development of several next-generation coronavirus vaccines, such as exosome-based, virus-like particle (VLP), mucosal, and nanomaterial-based vaccines. Finally, we highlight the key challenges and critical areas for future research to address the evolving threat of SARS-CoV-2 subvariants and to develop strategies for combating the emergence of new viral threats, thereby improving preparedness for future pandemics.

Self-Amplifying RNA: Advantages and Challenges of a Versatile Platform for Vaccine Development

Self-amplifying RNA is synthetic nucleic acid engineered to replicate within cells without generating viral particles. Derived from alphavirus genomes, saRNA retains the non-structural elements essential for replication while replacing the structural elements with an antigen of interest. By enabling efficient intracellular amplification, saRNA offers a promising alternative to conventional mRNA vaccines, enhancing antigen expression while requiring lower doses. However, this advantage comes with challenges. In this review, we highlight the key limitations of saRNA technology and explore potential strategies to overcome them. By identifying these challenges, we aim to provide insights that can guide the future design of saRNA-based therapeutics, extending their potential beyond vaccine applications.

A systems biology approach to define SARS-CoV-2 correlates of protection

Correlates of protection (CoPs) for SARS-CoV-2 have yet to be sufficiently defined. This study uses the machine learning platform, SIMON, to accurately predict the immunological parameters that reduced clinical pathology or viral load following SARS-CoV-2 challenge in a cohort of 90 non-human primates. We found that anti-SARS-CoV-2 spike antibody and neutralising antibody titres were the best predictors of clinical protection and low viral load in the lung. Since antibodies to SARS-CoV-2 spike showed the greatest association with clinical protection and reduced viral load, we next used SIMON to investigate the immunological features that predict high antibody titres. It was found that a pre-immunisation response to seasonal beta-HCoVs and a high frequency of peripheral intermediate and non-classical monocytes predicted low SARS-CoV-2 spike IgG titres. In contrast, an elevated T cell response as measured by IFNγ ELISpot predicted high IgG titres. Additional predictors of clinical protection and low SARS-CoV-2 burden included a high abundance of peripheral T cells. In contrast, increased numbers of intermediate monocytes predicted clinical pathology and high viral burden in the throat. We also conclude that an immunisation strategy that minimises pathology post-challenge did not necessarily mediate viral control. This would be an important finding to take forward into the development of future vaccines aimed at limiting the transmission of SARS-CoV-2. These results contribute to SARS-CoV-2 CoP definition and shed light on the factors influencing the success of SARS-CoV-2 vaccination.

Next-Generation Adenoviral Vector-Based Vaccines for Severe Acute Respiratory Syndrome Coronavirus-2

This review systematically revises adenovirus (Ad) biology, vector structure, immune responses, and currently available Ad vector COVID-19 vaccines. It analyzes the challenges associated with the Ad vector-based vaccines, including preexisting vector immunity and other side effects. Moreover, this review explores novel and innovative strategies to overcome these constraints for developing next-generation vaccines for broad protection to cover emerging SARS-CoV-2 variants. The future refinement of Ad vaccine platforms will be pivotal in achieving durable immunity against emerging variants for global preparedness.

Development of a novel adenovirus type 4 vector as a promising respiratory vaccine vehicle

Introduction

Adenovirus (Ad) vectors are widely used for gene delivery, and some of them have been approved for vaccine development. In particular, the recombinant COVID-19 vaccine for inhalation, which was developed using adenovirus type 5 (Ad5), represents a milestone in respiratory immunization. Owing to the high pre-existing immunity (PEI) to Ad5, the development of an adenoviral vector with lower PEI and higher immunogenicity has been explored. However, the majority of the developed novel Ad vectors showed suboptimal immunogenicity compared to Ad5 in animal models.

Method

In this study, we constructed a novel replication-deficient viral vector based on human adenovirus type 4 (Ad4), which has long been used as a live virus vaccine with a favorable safety profile in the U.S. military. The mice were immunized intramuscularly or intranasally with an Ad4-vectored vaccine to verify immune responses and protective efficacy.

Results

Compared with Ad5, the novel Ad4 vector showed comparable viral growth kinetics and transgene expression in cells and similar exogenous protein expression and distribution in mice. Furthermore, the Ad4-vectored vaccine elicited superior humoral and cellular responses and protective effects when vaccinated intranasally than those triggered by the Ad5-vectored vaccine. Finally, the heterologous Ad5 prime and Ad4 boost immunization showed better immunogenicity and protective efficacy.

Discussion

This study broadens the research trajectory of adenovirus-vectored vaccines and offers a new option for the development of recombinant viral-vectored vaccines.

Lessons from the PROTECT-CH COVID-19 platform trial in care homes

Background

Coronavirus disease-2019 was associated with significant mortality and morbidity in care homes in 2020-1. Repurposed antiviral drugs might reduce morbidity and mortality through reducing viral transmission, infection, replication and inflammation. We aimed to compare the safety and efficacy of potential antiviral drugs in care home residents.

Methods

We designed a cluster-randomised, open-label, blinded end-point platform trial to test drugs in a postexposure prophylaxis paradigm. Participants aged 65+ years from United Kingdom care homes, with or without nursing, were eligible for participation. Care homes were to be allocated at random by computer to administer 42 days of antiviral agent (ciclesonide or niclosamide) plus standard care versus standard care alone to residents. The primary outcome at 60 days after randomisation comprised the most serious outcome, which was defined as all-cause mortality, all-cause hospitalisation, severe acute respiratory syndrome coronavirus 2 infection or no infection. Analysis would be by intention to treat using ordinal logistic regression. Other outcomes included individual components of the primary outcome, transmission, plus health economic and process evaluation outcomes. The planned sample size was 300 care homes corresponding to 9600 residents. With ~40% of care homes predicted to develop an outbreak during the trial, we needed to recruit 750 homes/24,000 residents.

Results

We initiated the trial including protocol, approvals, insurance, website, database, data algorithms, intervention selection and training materials. We built a network of principal investigators and staff (91) and care homes (299) to support the trial. However, we never contracted care homes or general practitioners since the trial was stopped in September 2021, as vaccination in care homes had significantly reduced infections. Multiple delays significantly delayed the start date, such as: (1) reduced prioritisation of pandemic trials in 2021; (2) cumbersome mechanisms for choosing the investigational medicinal products; (3) contracting between National Institute for Health and Care Research and the investigational medicinal product manufacturers; (4) publicising the investigational medicinal products; (5) identification of sufficient numbers of care homes; (6) identification and contracting with several thousand general practitioners; (7) limited research nurse availability and (8) identification of adequate insurance to cover care homes for research. Generic challenges included working across the four home nations with their different structures and regulations.

Limitations

The feasibility of contracting between the sponsor and the principal investigators, general practitioners and care homes; screening, consent and treatment of care home residents; data acquisition and the potential benefit of postexposure prophylaxis were never tested.

Conclusions

The success of vaccination meant that the role of postexposure prophylaxis of coronavirus disease-2019 in care home residents was not tested. Significant progress was made in developing the infrastructure and expertise necessary for a large-scale clinical trial of investigational medicinal products in United Kingdom care homes.

Future work

The role of postexposure prophylaxis of coronavirus disease-2019 in care home residents remains undefined. Significant logistical barriers to conducting research in care homes need to be removed urgently before future studies are possible. Further work is required to develop the infrastructure for clinical trials of investigational medicinal products in care homes. Serious consideration should be given to building and then hibernating a pandemic-ready platform trial suitable for care home research.

Funding

This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number NIHR133443.

Accelerated vaccine process development by orthogonal protein characterization

The COVID-19 pandemic altered the vaccine development paradigm with accelerated timelines from concept through clinical safety and efficacy. Characterization and release assays for vaccine programs were developed under similar time constraints to support bioprocess development, scaleup and formulation. During the development of these vaccines, SARS-CoV-2 variants of concern (VOCs) emerged requiring integration of additional antigens into the target product profile. Biochemical testing to support the addition of new antigen variants (identity, quantity, antigenicity/potency) needed substantial re-development. Here we present a reversed-phase high-performance liquid-chromatography method for antigen purity with orthogonal identification characterization comprising of Simple Wes and liquid-chromatography tandem mass spectrometry (LC/MS/MS) to support accelerated process development for recombinant protein vaccines. This suite of assays was deployed to support rapid, scientific decision-making enabling the transition from completion of a placebo-controlled dose-ranging Phase 2 study to the start of the global Phase 3 safety and efficacy trial in less than 2 weeks.

Key considerations for a prostate cancer mRNA vaccine

Prostate cancer has the second highest cancer mortality rate in the UK in males. Early prostate cancer is typically asymptomatic, with diagnosis at a locally advanced or metastatic stage. In addition, the inherent heterogeneity of prostate cancer tumours differs significantly in terms of genetic, molecular, and histological features. The successful treatment of prostate cancer is therefore exceedingly challenging. Immunotherapies, particularly therapeutic vaccines, have been widely used in preclinical and clinical studies to treat various cancers. Sipuleucel-T was the first cancer vaccine approved by the FDA for the treatment of asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC), ushering in a new era of immunotherapy. In this review, the latest immunotherapy strategies for prostate cancer are considered with key tumour-associated antigens (TAA) and tumour-specific antigens (TSA) highlighted. The key components of mRNA vaccines include in vitro transcription, stability, and immunogenicity. Finally, strategies to circumvent in vivo mRNA degradation and approaches to optimise in vitro transcription (IVT) process are also discussed.

New-onset hematologic disorders following COVID-19 vaccination: a systematic review

Purpose

Coronavirus disease 2019 (COVID-19) vaccination reduced morbimortality rates due to severe acute respiratory syndrome coronavirus 2 infection worldwide. However, various complications have been reported, including hematologic disorders.

Materials and Methods

We conducted a systematic review to synthesize and analyze the current available evidence on the development of hematological disorders associated with COVID-19 vaccination.

Results

A total of 227 patients were reported in the papers that were selected to be included. There was a slight predominance of females (n=114, 50.22%) compared to males (n=113, 49.78%), and the calculated mean age was 54.86±18.94 years. The most frequently reported hematological disorders were Immune thrombocytopenic purpura (n=58, 25.55%), followed by thrombotic thrombocytopenic purpura (n=38, 16.74%). The less frequently recorded cases were acquired factor XIII/13 deficiency (n=2, 0.88%) and pernicious anemia (n=2, 0.88%). Messenger RNA (mRNA)-based COVID-19 vaccines, including Pfizer BioNTech 162b2 (n=106, 46.70%), Moderna mRNA 127-3 (n = 42, 18.50%), and the Bivalent vaccine (n = 1, 0.44%), were the most prevalent (n=150, 66.08%). Most cases developed after the first dose (n=120, 52.86%). In most cases, patient outcomes were favorable (n=175, 77.09%), but there were significant mortality cases (n=23, 10.13%).

Conclusion

Our findings suggest close monitoring of patients who receive the first dose with mRNA technology vaccines, regardless of sex, especially in adults, as they appear more vulnerable to developing hematologic disorders.

Trial Registration

PROSPERO Identifier: CRD42023452589.

Viral and host factors associated with SARS-CoV-2 disease severity in Georgia, USA

While SARS-CoV-2 vaccines have shown strong efficacy, the continued emergence of new viral variants raises concerns about the ongoing and future public health impact of COVID-19, especially in locations with suboptimal vaccination uptake. We investigated viral and host factors, including vaccination status, that were associated with SARS-CoV-2 disease severity in a setting with low vaccination rates. We analyzed clinical and demographic data from 1,957 individuals in the state of Georgia, USA, coupled with viral genome sequencing from 1,185 samples. We found no specific mutations associated with disease severity. Compared to those who were unvaccinated, vaccinated individuals experienced less severe SARS-CoV-2 disease, and the effect was similar for both variants. Vaccination within the prior 3-9 months was associated with decreased odds of moderate disease, severe disease, and death. Older age and underlying health conditions, especially immunosuppression and renal disease, were associated with increased disease severity. Overall, this study provides insights into the impact of vaccination status, variants/mutations, and clinical factors on disease severity in SARS-CoV-2 infection when vaccination rates are low. Understanding these associations will help refine and reinforce messaging around the crucial importance of vaccination in mitigating the severity of SARS-CoV-2 disease.

SARS-CoV-2 serotyping based on spike antigenicity and its implications for host immune evasion

BACKGROUND

As SARS-CoV-2 continues to spread and evolve, new variants/sub-variants emerge, raising concerns about vaccine-induced immune escape. Here, we conducted a systematic analysis of the serology and immunogenicity of major circulating variants/sub-variants of SARS-CoV-2 since the outbreak.

METHODS

We expressed and purified trimeric S proteins from 21 SARS-CoV-2 variants, with SARS-CoV included as an outgroup. Mice were immunized, and the resulting antisera were tested for binding antibodies after the third dose injection, and for neutralizing antibodies (NAbs) after both the second and third doses. Using pseudovirus neutralization assays, we evaluated cross-neutralization among major circulating variants. By integrating serological classification, antigenic mapping, and 3D landscape analysis, we explored the antigenic relationships among different SARS-CoV-2 variants and their impact on serological responses.

FINDINGS

Based on the cross-neutralization activities of the sera from different S protein vaccinations and antigenicity analyses, we grouped the 21 lineages into six serotypes. Particularly, BA.2.86 and JN.1 had very weak cross-neutralization with all other SARS-CoV-2 sub-variants tested and were grouped into a separate serotype, Serotype VI.

INTERPRETATION

This systematic study contributes to a better understanding of the evolution of SARS-CoV-2 and its antigenic characteristics and provides valuable insights for vaccine development.

FUNDING

This study was supported by the National Key R&D Program of China (2023YFC2307801, 2020YFA0509202 and 2021YFA1300803), the National Natural Science Foundation of China (82222040 and 82072289), CAS Project for Young Scientists in Basic Research (YSBR-083) and Beijing Nova Program of Science and Technology (20220484181).

COVID-19 vaccination and neurological complications: A cross-sectional observational study from a tertiary care centre of North India

Vaccine hesitancy, anti-Vax campaigners and misinformation hound the administration of vaccines. Our study, conducted at Malwa region of the Punjab, India, was systematically carried out to look for adverse neurological effects after COVID-19 vaccination, given to 1000 people (>18 years and <60 years) who had received either single or multiple doses. No major neurological complications were found; the only side-effect was a transitory headache in 15% of the participants.

Unlocking the potential of circular RNA vaccines: a bioinformatics and computational biology perspective

Bioinformatics has significantly advanced RNA-based therapeutics, particularly circular RNAs (circRNAs), which outperform mRNA vaccines, by offering superior stability, sustained expression, and enhanced immunogenicity due to their covalently closed structure. This review highlights how bioinformatics and computational biology optimise circRNA vaccine design, elucidates internal ribosome entry sites (IRES) selection, open reading frame (ORF) optimisation, codon usage, RNA secondary structure prediction, and delivery system development. While circRNA vaccines may not always surpass traditional vaccines in stability, their production efficiency and therapeutic efficacy can be enhanced through computational strategies. The discussion also addresses challenges and future prospects, emphasizing the need for innovative solutions to overcome current limitations and advance circRNA vaccine applications.

A Big Data Optimization Approach for Estimating the Time-Dependent Effectiveness Profiles Against Hospitalization for Double- and Single-Dose Schemes: Study Case, COVID-19 in Elderly Mexicans

Background: The COVID-19 pandemic and its handling have made evident the cardinal role of vaccines in controlling the spread of diseases, especially around developed cities. Therefore, precisely characterizing their response has taken a relevant role. Unfortunately, substantial evidence has proven the time dependence of their effectiveness, requiring new approaches that account not only for single value estimations but also for time changes in the effectiveness. Methodology: A strategy is proposed to estimate a continuous profile representing the time evolution of the effectiveness against hospitalization. Such a strategy is showcased by characterizing the hospitalization behavior of elderly Mexicans during the COVID-19 pandemic (more than 15 million individuals). Results: It is demonstrated that practically total protection against hospitalization can be reached during a noticeable period. However, a substantial depletion in effectiveness occurs after such a plateau. Our methodology provides a continuous profile instead of only a few discrete values, offering insights unattainable by traditional strategies. Furthermore, the obtained profile details allowed for decoupling the effects of each dose independently, enabling the estimation of the expected effectiveness profile for a single-dose scheme. Conclusions: The comparison between both schemes (one or two doses) demonstrated that the two-dose scheme is far superior, offering a better investment for public health authorities. Concerning the strategy, the description capabilities of the proposal highly outperform currently available methodologies, allowing for detailed profiles describing the evolution of efficacy to be obtained. This not only opens the opportunity for fair comparison among available vaccines but also creates a tool for researchers studying the immune responses of polydose vaccines.

Immunogenicity of adjuvanted recombinant SARS-CoV-2 spike protein vaccine after earlier mRNA vaccine doses

BACKGROUND

To support heterologous vaccine regimens, periodic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revaccination requires immunogenicity and safety data for adjuvanted protein-based vaccines following prior mRNA doses.

OBJECTIVE

We sought to assess noninferiority of neutralizing antibody (nAb) titers following a second dose versus a first dose (in a prior study) of an SARS-CoV-2 protein-based vaccine (NVX-CoV2373) administered following a primary series (2 or 3 doses) of an mRNA vaccine.

METHODS

This phase 3, open-label study (2019nCoV-312/NCT05875701) enrolled participants who had received 1 dose of the ancestral SARS-CoV-2 protein-based vaccine in an earlier study (2019nCoV-307/NCT05463068) after a primary series (2 or 3 doses) of a commercial mRNA vaccine. In the current study, participants received an additional dose of protein vaccine (ancestral [n = 104] or Omicron BA.5 [n = 40]) at least 180 days after their previous study dose.

RESULTS

The study enrolled 144 participants. The ratio of anti-Wuhan nAbs (geometric mean titer) at day 28 after this study dose (ancestral 393.2 IU/mL [95% CI 318.0-468.2]) versus previous study dose (396.6 IU/mL [95% CI 328.7-478.6]) was 1.0 (0.8-1.2), meeting noninferiority. The seroresponse rate difference between doses was 7.4% (95% CI -1.2% to 16.5%), also meeting noninferiority. Omicron BA.5 nAb titers suggest cross-protection against emerging variants. The anti-Wuhan nAb ratio at day 28 between Omicron BA.5 vaccine dose in this study (835.0 [597.1-1167.6]) versus the ancestral vaccine in the previous study (436.0 [305.6-622.2]) was 1.9 (1.5-2.5), exceeding superiority criterion. Local and systemic reactions were similar between doses and strains in both studies.

CONCLUSION

A heterologous regimen of 2 adjuvanted, recombinant spike protein vaccine doses following multiple mRNA vaccine doses produced robust immune responses, exhibiting cross-reactivity to some newer variants.

Proceedings of the 2023 Annual Scientific Meeting of the French Society of Toxicologic Pathology (SFPT) on Preclinical Development and Therapeutic Applications of mRNA-Based Technologies

The 2023 annual scientific meeting of the French Society of Toxicologic Pathology (Société Française de Pathologie Toxicologique, SFPT), entitled "mRNA-based technologies: preclinical development and therapeutic applications," was held in Lyon (France) on May 25 to 26, 2023. The aim of the meeting was to discuss the biology, immunology, and preclinical development of messenger RNA (mRNA)-based vaccines and therapeutics, including immuno-oncology and rare diseases, as well as the regulatory aspect of the COVID-19 vaccines and an overview of the principles and applications of in situ hybridization techniques. This article presents the summary of five lectures along with selected figures, tables, and key literature references on this topic.

T and B cell responses in different immunization scenarios for COVID-19: a narrative review

Vaccines against COVID-19 have high efficacy and low rates of adverse events. However, none of the available vaccines provide sterilizing immunity, and reinfections remain possible. This review aims to summarize the immunological responses elicited by different immunization strategies, examining the roles of homologous and heterologous vaccination and hybrid immunity. Homologous vaccination regimens exhibit considerable variation in immune responses depending on the vaccine platform, particularly concerning antibody titers, B cell activation, and T cell responses. mRNA vaccines, such as mRNA-1273 and BNT162b2, consistently generate higher and more durable levels of neutralizing antibodies and memory B cells compared to adenovirus-based vaccines like Ad26.COV2.S and ChAdOx1. The combination of two distinct vaccine platforms, each targeting different immune pathways, seems to be more effective in promoting long-lasting B cell responses and potent T cell responses. The high heterogeneity of the available studies, the different dosing schemes, the succession of new variants, and the subjects' immunological background do not allow for a definitive conclusion. Overall, heterologous vaccination strategies, combining sequentially viral vector and mRNA may deliver a more balanced and robust humoral and cellular immune response compared to homologous regimens. Hybrid immunity, which arises from SARS-CoV-2 infection preceded or followed by vaccination produces markedly stronger immune responses than either vaccination or infection alone. The immune response to SARS-CoV-2 variants of concern varies depending on both the vaccine platform and prior infection status. Hybrid immunity leads to a broader antibody repertoire, providing enhanced neutralization of variants of concern. Heterologous vaccination and hybrid immunity may provide further opportunities to enhance immune responses, offering broader protection and greater durability of immunity. However, from all-cause mortality, symptomatic or severe COVID, and serious adverse events at present it is not possible to infer different effects between homologous and heterologous schemes. Next-generation vaccines could involve tweaks to these designs or changes to delivery mechanisms that might improve performance.

Differential efficacy of first licensed western vaccines protecting without immunopathogenesis Wuhan-1-challenged hamsters from severe COVID-19

Four COVID-19 vaccines were developed, tested, and authorized early in Europe and the US. Comirnaty and Spikevax are mRNA-based, whereas Jcovden and Vaxzevria utilize adenoviral vectors (AdV). We described a hamster model of COVID-19 utilizing Wuhan-1 strain SARS-CoV-2, in which vaccine-associated immunopathogenesis can be induced by Alum-adjuvanted Spike protein (Alum+S). Such animals were vaccinated with the authorized vaccines or Alum+S, challenged, and examined. All vaccinated hamsters produced antibodies targeting S. Neutralizing antibodies (nAb) were induced only by authorized vaccines. While nAbs were present after one vaccination with AdV-vaccines, mRNA vaccines needed a boost immunization. Upon challenge, all authorized vaccines protected from severe disease. Less tissue damage and no live virus (one exception) were detectable in the lungs. In contrast, Alum+S immunized hamsters developed VAERD. Our data reveal the absence of induction of VAERD by early commercial vaccines in hamsters, while animals´ immune responses and protection seem to match the clinical vaccine efficacy.

Stabilizing Prefusion SARS-CoV-2 Spike by Destabilizing the Postfusion Conformation

Background/Objectives: As with many viral fusion proteins, the native conformation of SARS-CoV-2 Spike is metastable. Most COVID-19 vaccines utilize a stabilized Spike (Spike-2P) containing two proline substitutions, and subsequently, a further stabilized variant with four additional proline substitutions, Spike-6P, has been developed. In an alternative approach, we introduced two aspartic acid residues (2D) in the HR1 region of Spike at positions that are exposed and buried in the pre- and postfusion states, respectively, to destabilize the postfusion conformation. Methods: The recombinant protein constructs were expressed in a mammalian cell culture and characterized for their yield and antigenicity, and the formulations were then used to immunize hamsters. After two immunizations, the hamsters were challenged with live B.1.351 SARS-CoV-2 virus for an evaluation of the protective efficacy. Results: The introduction of the two aspartic acid mutations resulted in an approximately six-fold increase in expression, comparable to that in Spike-2P. When the 2D mutations were combined with the above four proline mutations (Spike-4P-2D), this led to a further three- to four-fold enhancement of protein expression, similar to that seen in Spike-6P. When formulated with the oil-in-water emulsion adjuvant Sepivac SWE, the 2P, 2D, 6P, and 4P-2D Spike variants all protected female hamsters against heterologous challenge with the B.1.351 SARS-CoV-2 virus and elicited high titers of neutralizing antibodies. Conclusions: We suggest that destabilization of the postfusion conformation through the introduction of charged amino acids at sites that are exposed in the pre- and buried in the postfusion conformation offers a general strategy to enhance the yield and stability of the native, prefusion conformation of viral surface proteins.

Assessing the impact of COmorbidities and Sociodemographic factors on Multiorgan Injury following COVID-19: rationale and protocol design of COSMIC, a UK multicentre observational study of COVID-negative controls

INTRODUCTION

SARS-CoV-2 disease (COVID-19) has had an enormous health and economic impact globally. Although primarily a respiratory illness, multi-organ involvement is common in COVID-19, with evidence of vascular-mediated damage in the heart, liver, kidneys and brain in a substantial proportion of patients following moderate-to-severe infection. The pathophysiology and long-term clinical implications of multi-organ injury remain to be fully elucidated. Age, gender, ethnicity, frailty and deprivation are key determinants of infection severity, and both morbidity and mortality appear higher in patients with underlying comorbidities such as ischaemic heart disease, hypertension and diabetes. Our aim is to gain mechanistic insights into the pathophysiology of multiorgan dysfunction in people with COVID-19 and maximise the impact of national COVID-19 studies with a comparison group of COVID-negative controls.

METHODS AND ANALYSIS

COmorbidities and Sociodemographic factors on Multiorgan Injury following COVID-19 (COSMIC) is a prospective, multicentre UK study which will recruit 200 subjects without clinical evidence of prior COVID-19 and perform extensive phenotyping with multiorgan imaging, biobank serum storage, functional assessment and patient reported outcome measures, providing a robust control population to facilitate current work and serve as an invaluable bioresource for future observational studies.

ETHICS AND DISSEMINATION

Approved by the National Research Ethics Service Committee East Midlands (REC reference 19/EM/0295). Results will be disseminated via peer-reviewed journals and scientific meetings.

TRIAL REGISTRATION NUMBER

COSMIC is registered as an extension of C-MORE (Capturing Multi-ORgan Effects of COVID-19) on ClinicalTrials.gov (NCT04510025).

COVID-19 related complications

The COVID-19 pandemic has significantly impacted global healthcare systems, revealed vulnerabilities and prompted a re-evaluation of medical practices. Acute complications from the virus, including cardiovascular and neurological issues, have underscored the necessity for timely medical interventions. Advances in diagnostic methods and personalized therapies have been pivotal in mitigating severe outcomes. Additionally, Long COVID has emerged as a complex challenge, affecting various body systems and leading to respiratory, cardiovascular, neurological, psychological, and musculoskeletal problems. This broad spectrum of complications highlights the importance of multidisciplinary management approaches that prioritize therapy, rehabilitation, and patient-centered care. Vulnerable populations such as paediatric patients, pregnant women, and immunocompromised individuals face unique risks and complications, necessitating continuous monitoring and tailored management strategies to reduce morbidity and mortality associated with COVID-19.

SARS-CoV-2 Fusion Peptide-Directed Antibodies Elicited by Natural Infection Mediate Broad Sarbecovirus Neutralization

Studies have demonstrated that repeated mRNA vaccination enhances the breadth of neutralization against diverse SARS-CoV-2 variants. However, the development of antibodies capable of neutralizing across the Coronavirinae subfamily is poorly understood. In this study, we analyze serum samples to determine their neutralization breadth and potency and identify their antigenic targets. Using a cohort of older individuals and healthcare workers, we track correlates of broad neutralizing responses, including fusion peptide (FP) antibody elicitation. We find that although broadly neutralizing responses are often a result of RBD-specific antibodies, a rare subset of donors produce FP-specific broadly neutralizing responses. Interestingly, FP-specific antibodies are not observed in COVID-naive individuals irrespective of vaccination regimen, but rather, they occur following natural infection or vaccine breakthrough. This study highlights the epitope targets underpinning broadly neutralizing antibody responses to coronaviruses and suggests that existing vaccines are insufficient to promote the elicitation of FP-directed broadly neutralizing coronavirus antibodies.

Death Risk Response of High-Altitude Resident Populations to COVID-19 Vaccine: A Retrospective Cohort Study

Vásquez-Velásquez, Cinthya, Diego Fano-Sizgorich, and Gustavo F. Gonzales. Death risk response of high-altitude resident populations to COVID-19 vaccine: a retrospective cohort study. High Alt Med Biol. 26:37-44, 2025. Background: Peru had one of the highest mortality rates caused by the coronavirus disease 2019 (COVID-19) pandemic worldwide. Vaccination significantly reduces mortality. However, the effectiveness of vaccination might differ at different altitudinal levels. The study aimed to evaluate the effect modification of altitude on the association between vaccination and COVID-19 mortality in Peru. Methodology: A retrospective cohort, using open access databases of deaths, COVID-19 cases, hospitalizations, and vaccination was obtained from the Peruvian Ministry of Health. Deaths due to COVID-19 were evaluated in vaccinated and nonvaccinated patients. Crude (RR) and adjusted relative risks (aRR) were calculated using generalized linear models of Poisson family with robust variances. Models were adjusted for age, sex, pandemic wave, and Human Development Index. To evaluate the interaction by altitude, a stratified analysis by this variable was performed. The variable altitude was categorized as, 0-499 m (828,298 cases), 500-1,499 m (64,735 cases), 1,500-2,499 m (106,572 cases), and ≥2,500 m (179,004 cases). The final sample studied included 1,362,350 cases. Results: The vaccine showed a considerable reduction of death risk with the second (aRR: 0.41, 95% confidence interval [CI]: 0.38-0.44) and third doses (aRR: 0.21, 95% CI: 0.20-0.23). In the adjusted and interaction model, it can be observed that medium and high altitude present a higher risk of death compared to sea level (aRR: 2.58 and 2.03, respectively). Likewise, the two doses' group presents an aRR:1.22 for medium altitude (1,500-2,499 m) and 1.6 for high altitude (≥2,500 m), compared with low-altitude population, suggesting that the action of vaccination at high altitude is altered by the effect of the altitude itself. Conclusions: Altitude might modify the protective effect of SARS-CoV-2 vaccine against COVID-19 death.

The development of therapeutics and vaccines against COVID-19

Since the COVID-19 pandemic, it has caused a great threat to the global economy and public health, initiatives have been launched to control the spread of the virus. To explore the efficacy of drugs, a large number of clinical trials have been carried out, with the purpose of providing guidelines based on high-quality evidence for clinicians. We mainly discuss therapeutic agents for COVID-19 and explain the mechanism, including antiviral agents, tocilizumab, Janus kinase (JAK) inhibitors, neutralizing antibody therapies and corticosteroids. In addition, the COVID-19 vaccine has been proven to be efficacious in preventing SARS-CoV-2 infection. We systematically analyzed four mainstream vaccine platforms: messenger RNA (mRNA) vaccines, viral vector vaccines, inactivated vaccines and protein subunit vaccines. We evaluated the therapeutic effects of drugs and vaccines through enumerating the most typical clinical trials. However, the emergence of novel variants has further complicated the interpretation of the available clinical data, especially vaccines and antibody therapies. In the post-epidemic era, therapeutic agents are still the first choice for controlling the progression of disease, whereas the protective effect of vaccines against different strains should be assessed comprehensively.

Globally approved vaccines for COVID-19: a systematic review

COVID-19 caused a public health emergency, which instituted a global effort to develop vaccines using different platforms, such as basic types and new-generation vaccines. Considering the importance of vaccination in preventing the severity of infectious diseases and the success in developing and approving vaccines against COVID-19 in record time, it is essential to learn about the characteristics of these vaccines. This study aimed to conduct a structured, systematic review following the PRISMA guideline, to analyze the general characteristics of vaccines approved globally for use against COVID-19. We used the list of approved vaccines available by the WHO as guidance to search for studies in the literature. We searched the terms "SARS-CoV-2 and vaccine and safety and efficacy" in the MEDLINE via PUBMED and Web of Science databases. We conducted the research on both bases, including complete articles published from January 2020 to June 2023. The selection of files occurred between May/2021 and June/2023. Therefore, the paper did not consider articles published after this period or vaccines approved after this moment. This study only included approved vaccines; phase three studies published in English. We found 11 published articles from phase three that met the established criteria. The vaccines included in this study were: Cominarty, mRNA-1273 or Spikevax, Vaxzevria or AZD1222 or Covishield, CoronaVac or PicoVacc, and Ad26.COV2.S, SputnikV or Gam-Covid-Vac, Covaxin, NVX-CoV2373 or Covovax or Nuvaxovid, WIV04 and HB02, CoVLP or Covifenz and Convidecia or Ad5-nCoV. We summarized the main findings of each vaccine, considering the vaccine composition, number of doses, efficacy analyses, and main adverse effects. In general, the vaccines had high efficacy rates and few adverse effects. Efficacy values are important for vaccine approval, but they will not necessarily reflect the real-world impact of vaccination. It was seen that the effectiveness of COV2.S, CoronaVac/PicoVacc, Cominarty, and Covaxin vaccines was lower than the efficacy, whereas, for AZD1222/Vaxzevria/Covishield, the two parameters remained at similar rates. All vaccines evaluated have different compositions, dosages, populations, and study designs. All are effective in at least preventing symptomatic COVID-19, causing mild or moderate adverse effects when present.

Assessment of COVID-19 Vaccine Effectiveness Against SARS-CoV-2 Infection, Hospitalization and Death in Mexican Patients with Metabolic Syndrome from Northeast Mexico: A Multicenter Study

Background/Objectives: Metabolic syndrome (MetS) is a predisposing factor for severe COVID-19. The effectiveness of COVID-19 vaccines in patients with MetS has been poorly investigated. The aim of this study was to evaluate the effectiveness of COVID-19 vaccination before (BO) and after the Omicron (AO) SARS-CoV-2 variant in patients with MetS. Methods: This retrospective observational study was carried out in a total of 3194 patients with MetS and a COVID-19 PCR or rapid antigen test. The main outcomes were vaccine effectiveness against infection, hospitalization and death resulting from COVID-19. Results: BO, only two doses of BNT162b2 were effective against infection, this effectiveness was lost AO. Also, with two doses, BNT162b2, ChAdOx1 and CoronaVac were effective against hospitalization BO; however, AO, only BNT162b2 and CoronaVac were effective. Regarding death as an outcome of COVID-19, two doses of BNT162b2 were effective BO, whereas AO, BNT162b2 and CoronaVac were 100% effective. BO the presentation of a sore throat increased after two doses of COVID-19 vaccine regardless of the type, and the presentation of dyspnea diminished after two doses of BNT162b2 and CoronaVac. Conclusions: The SARS-CoV-2 Omicron variant has impacted vaccines' effectiveness against hospitalization and death in patients with MetS. A tailored vaccination scheme for patients with MetS should be implemented due to the varying effectiveness rates observed in our study.

Population shift in antibody immunity following the emergence of a SARS-CoV-2 variant of concern

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) exhibit escape from pre-existing immunity and elicit variant-specific immune responses. In South Africa, the second wave of SARS-CoV-2 infections was driven by the Beta VOC, which coincided with the country-wide National COVID-19 Antibody Survey (NCAS). The NCAS was conducted between November 2020 and February 2021 to understand the burden of SARS-CoV-2 infection through seroprevalence. We evaluated 649 NCAS sera for spike binding and pseudovirus neutralizing antibodies. We classified individuals as ancestral or D614G neutralizers (114/649), Beta neutralizers (96/649), double neutralizers (375/649) or non-neutralizers (62/649). We observed a consistent decrease in preferential neutralization against the D614G variant from 68 to 18% of individuals over the four sampling months. Concurrently, samples with equivalent neutralization of both variants, or with enhanced neutralization of the Beta variant, increased from 32 to 82% of samples. Neutralization data showed that geometric mean titers (GMTs) against D614G dropped 2.4-fold, while GMTs against Beta increased 2-fold during this same period. A shift in population humoral immunity in favor of Beta-directed or cross-neutralizing antibody responses, paralleled the increase in genomic frequency of the Beta variant in South Africa. Understanding similar population immunity shifts could elucidate immunity gaps that drive SARS-CoV-2 evolution.

Innovations in vaccine design: Computational tools and techniques

The advancements in computational tools have revolutionized vaccine development by organizing and analyzing large-scale immunological data through immuno-informatics. This field combines computational and mathematical approaches to model molecular interactions during antigen presentation and processing. These tools have significantly accelerated vaccine development, making it more efficient and cost-effective. Applications such as SCWRL and SCAP help in side chain and backbone modeling to improve antibodies and forecast secondary structures. Multi-graft and multivalent scaffolds present antigens to elicit strong immune responses; antibodyomics studies the sequences of antibodies to find antibodies that can neutralize. It is another traditional way of doing vaccines where the pathogen's genome is scanned by diacide such as Vaxign to identify the likely vaccine agents. Codon optimization, as implemented with the aid of COOL and OPTIMIZER tools, enhances the output of proteins among which vaccines are needed. These tools also allow for predicting epitope structures the more accurately, or so. Prediction tools that include immunogenicity screening tests that map B-cell epitope and T-cell epitope such as ElliPro and DiscoTope aid in drug design, while the application of Fusion technologies facilitates vaccine development and kit diagnostics. The percentage of time trying to identify possible vaccine candidates is reduced alongside the costs with the application of these tools allowing the improvement in the prediction of vaccine candidates. The purpose of this chapter is to emphasize the invention of computational tools and methods that together are revolutionizing vaccine design and development and to underline the importance of tissue engineering and immunology advances.

Risk of SARS-CoV-2 infection and adverse outcomes among vaccinated patients with tuberculosis

OBJECTIVES

Limited data are available to assess breakthrough SARS-CoV-2 infections, medical utilization, and mortality in patients with tuberculosis (TB). The aim of this study was to examine the risk of COVID-19 and severe outcomes in patients with TB between January 2020 and March 2022.

STUDY DESIGN

US electronic medical records were used to identify TB and non-TB patients who completed the primary series of vaccination and had no prior COVID-19.

METHODS

Breakthrough infections and severe adverse outcomes, defined by the Centers for Disease Control and Prevention as hospitalization, need for mechanical ventilation and/or intensive care unit admission, or in-hospital mortality, following a positive SARS-CoV-2 polymerase chain reaction (PCR) test. Follow-up began 14 days after the primary vaccination series was completed and continued for 365 days.

RESULTS

The study included 15,541 TB and 15,541 non-TB patients. The risk of breakthrough infection was significantly higher in the TB group than in the non-TB group after controlling for age, sex, ethnicity, socioeconomic status, and lifestyles (adjusted HR, 1.444; 95 % CI, 1.321-1.579). Similar trends were observed in pre-specified subgroup analyses stratified by age, sex, and status of TB. Patients in the TB group had higher risks of emergency room visit and critical care admission [adjusted HRs, 1.244 (95 % CI, 1.175-1.316) and 1.404 (95 % CI, 1.182-1.668)].

CONCLUSIONS

Our study revealed a higher risk of COVID-19 breakthrough infections and adverse outcomes among patients with TB. Thus, besides priority COVID-19 vaccination, healthcare providers should continue vigilance for patients with TB.

Deucravacitinib: Adverse Events of Interest Across Phase 3 Plaque Psoriasis Trials

INTRODUCTION

Deucravacitinib, an oral, selective, allosteric tyrosine kinase 2 inhibitor, is approved in multiple countries for adults with moderate to severe plaque psoriasis who are candidates for systemic therapy. The safety and efficacy of deucravacitinib in psoriasis has been demonstrated through 3 years in the phase 3 POETYK PSO-1, PSO-2, and long-term extension (LTE) trials enrolling adults with moderate to severe plaque psoriasis.

METHODS

To review the effect of deucravacitinib treatment on adverse events of interest (AEIs) over 3 years in POETYK PSO-1, PSO-2, and LTE, cumulative exposure-adjusted incidence rates (EAIRs) of AEIs were recorded through 3 years.

RESULTS

AEIs and 3-year EAIRs of select infections included serious infections (2.5/100 person-years [PY]), COVID-19 (1.6/100 PY), and herpes zoster (0.6/100 PY). Excluding COVID-19, the serious infections EAIR was 0.9/100 PY. Major adverse cardiovascular event (MACE) and venous thromboembolism EAIRs were 0.3/100 PY and 0.1/100 PY, respectively. The EAIRs for malignancies were 0.9/100 PY overall and 0.5/100 PY, excluding nonmelanoma skin cancer (NMSC). Cutaneous events included acne (EAIR, 1.3/100 PY) and folliculitis (EAIR, 1.1/100 PY). Three-year cumulative EAIRs generally remained stable or decreased relative to 1-year rates. EAIRs of non-COVID-19 serious infections, malignancies excluding NMSC, and MACE through 3 years were consistent with rates for other antipsoriatic agents from clinical trials, disease registries, and real-world claims data.

CONCLUSION

In adults with plaque psoriasis treated with deucravacitinib, the cumulative incidence of AEIs remained comparable or decreased over 3 years of follow-up and aligned with comparison data for other antipsoriatic therapies.