Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine

Salivary immune responses after COVID-19 vaccination

mRNA-based COVID-19 vaccines have played a critical role in reducing severe outcomes of COVID-19. Humoral immune responses against SARS-CoV-2 after vaccination have been extensively studied in blood; however, limited information is available on the presence and duration of SARS-CoV-2 specific antibodies in saliva and other mucosal fluids. Saliva offers a non-invasive sampling method that may also provide a better understanding of mucosal immunity at sites where the virus enters the body. Our objective was to evaluate the salivary immune response after vaccination with the COVID-19 Moderna mRNA-1273 vaccine. Two hundred three staff members of the U.S. Centers for Disease Control and Prevention were enrolled prior to receiving their first dose of the mRNA-1273 vaccine. Participants were asked to self-collect 6 saliva specimens at days 0 (prior to first dose), 14, 28 (prior to second dose), 42, and 56 using a SalivaBio saliva collection device. Saliva specimens were tested for anti-spike protein SARS-CoV-2 specific IgA and IgG enzyme immunoassays. Overall, SARS-CoV-2-specific salivary IgA titers peaked 2 weeks after each vaccine dose, followed by a sharp decrease during the following weeks. In contrast to IgA titers, IgG antibody titers increased substantially 2 weeks after the first vaccine dose, peaked 2 weeks after the second dose and persisted at an elevated level until at least 8 weeks after the first vaccine dose. Additionally, no significant differences in IgA/IgG titers were observed based on age, sex, or race/ethnicity. All participants mounted salivary IgA and IgG immune responses against SARS-CoV-2 after receiving the mRNA-1273 COVID-19 vaccine. Because of the limited follow-up time for this study, more data are needed to assess the antibody levels beyond 2 months after the first dose. Our results confirm the potential utility of saliva in assessing immune responses elicited by immunization and possibly by infection.

Evaluating TRAIL and IP-10 alterations in vaccinated pregnant women after COVID-19 diagnosis and their correlation with neutralizing antibodies

Background

This study evaluates tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and interferon-γ-induced protein-10 (IP-10) in pregnant women with COVID-19 and their newborns, exploring the effects of antiviral treatments and vaccine-induced neutralizing antibody (Nab) inhibition on these key viral infection biomarkers.

Methods

We studied 61 pregnant women with past COVID-19 and either three (n=56) or four (n=5) doses of vaccination, and 46 without COVID-19 but vaccinated. We analyzed them and their newborns' blood for TRAIL, IP-10, and Nab levels using enzyme-linked immunosorbent assays (ELISA), correlating these with other clinical factors.

Results

Our study found lower TRAIL but higher IP-10 levels in maternal blood than neonatal cord blood, irrespective of past COVID-19 diagnosis. Cases diagnosed with COVID-19 < 4 weeks previously had higher maternal blood TRAIL levels (16.49 vs. 40.81 pg/mL, p=0.0064) and IP-10 (154.68 vs. 225.81 pg/mL, p=0.0170) than those never diagnosed. Antiviral medication lowered TRAIL and IP-10 in maternal blood without affecting Nab inhibition (TRAIL: 19.24 vs. 54.53 pg/mL, p=0.028; IP-10: 158.36 vs. 255.47 pg/mL, p=0.0089). TRAIL and IP-10 levels were similar with three or four vaccine doses, but four doses increased Nab inhibition (p=0.0363). Previously COVID-19 exposed pregnant women had higher Nab inhibition (p < 0.0001). No obvious correlation was found among TRAIL, IP-10, and Nab inhibition level.

Conclusions

Our study suggests that lower maternal TRAIL and higher IP-10 levels compared to neonatal cord blood coupled with a rise in both markers following COVID-19 diagnosis that could be reduced by antivirals indicates a correlation to infection severity. Higher vaccine doses enhance Nab inhibition, irrespective of antiviral medication use and independent of TRAIL or IP-10 levels, highlighting the significance and safety of adequate vaccination and antiviral use post-diagnosis in pregnant women.

Enhanced Omicron Variant Neutralization by a Human Antibody Tailored to Wild-Type and Delta-Variant SARS-CoV-2 RBDs

Given the previous SARS-CoV-2 pandemic and the inherent unpredictability of viral antigenic drift and shift, preemptive development of diverse neutralizing antibodies targeting a broad spectrum of epitopes is essential to ensure immediate therapeutic and prophylactic interventions during emerging outbreaks. In this study, we present a monoclonal antibody engineered for cross-reactivity to both wild-type and Delta RBDs, which, surprisingly, demonstrates enhanced neutralizing activity against the Omicron variant despite a significant number of mutations. Using an Escherichia coli inner membrane display of a human naïve antibody library, we identified antibodies specific to the wild-type SARS-CoV-2 receptor binding domain (RBD). Subsequent directed evolution via yeast surface display yielded JS18.1, an antibody with high binding affinity for both the Delta and Kappa RBDs, as well as enhanced binding to other RBDs (wild-type, Alpha, Beta, Gamma, Kappa, and Mu). Notably, JS18.1 (engineered for wild-type and Delta RBDs) exhibits enhanced neutralizing capability against the Omicron variant and binds to RBDs noncompetitively with ACE2, distinguishing it from other previously reported antibodies. This underscores the potential of pre-existing antibodies to neutralize emerging SARS-CoV-2 strains and offers insights into strategies to combat emerging viruses.

Harnessing the potential of the NALT and BALT as targets for immunomodulation using engineering strategies to enhance mucosal uptake

Mucosal barrier tissues and their mucosal associated lymphoid tissues (MALT) are attractive targets for vaccines and immunotherapies due to their roles in both priming and regulating adaptive immune responses. The upper and lower respiratory mucosae, in particular, possess unique properties: a vast surface area responsible for frontline protection against inhaled pathogens but also simultaneous tight regulation of homeostasis against a continuous backdrop of non-pathogenic antigen exposure. Within the upper and lower respiratory tract, the nasal and bronchial associated lymphoid tissues (NALT and BALT, respectively) are key sites where antigen-specific immune responses are orchestrated against inhaled antigens, serving as critical training grounds for adaptive immunity. Many infectious diseases are transmitted via respiratory mucosal sites, highlighting the need for vaccines that can activate resident frontline immune protection in these tissues to block infection. While traditional parenteral vaccines that are injected tend to elicit weak immunity in mucosal tissues, mucosal vaccines (i.e., that are administered intranasally) are capable of eliciting both systemic and mucosal immunity in tandem by initiating immune responses in the MALT. In contrast, administering antigen to mucosal tissues in the absence of adjuvant or costimulatory signals can instead induce antigen-specific tolerance by exploiting regulatory mechanisms inherent to MALT, holding potential for mucosal immunotherapies to treat autoimmunity. Yet despite being well motivated by mucosal biology, development of both mucosal subunit vaccines and immunotherapies has historically been plagued by poor drug delivery across mucosal barriers, resulting in weak efficacy, short-lived responses, and to-date a lack of clinical translation. Development of engineering strategies that can overcome barriers to mucosal delivery are thus critical for translation of mucosal subunit vaccines and immunotherapies. This review covers engineering strategies to enhance mucosal uptake via active targeting and passive transport mechanisms, with a parallel focus on mechanisms of immune activation and regulation in the respiratory mucosa. By combining engineering strategies for enhanced mucosal delivery with a better understanding of immune mechanisms in the NALT and BALT, we hope to illustrate the potential of these mucosal sites as targets for immunomodulation.

Coarse-Grained Simulation of mRNA-Loaded Lipid Nanoparticle Self-Assembly

Ionizable lipid-containing lipid nanoparticles (LNPs) have enabled the delivery of RNA for a range of therapeutic applications. In order to optimize safe, targeted, and effective LNP-based RNA delivery platforms, an understanding of the role of composition and pH in their structural properties and self-assembly is crucial, yet there have been few computational studies of such phenomena. Here we present a coarse-grained model of ionizable lipid and mRNA-containing LNPs. Our model allows access to the large length- and time-scales necessary for LNP self-assembly and is mapped and parametrized with reference to all-atom structures and simulations of the corresponding components at compositions typical of LNPs used for mRNA delivery. Our simulations reveal insights into the dynamics of self-assembly of such mRNA-encapsulating LNPs, as well as the subsequent pH change-driven LNP morphology and release of mRNA.

Effects of vaccination on COVID-19 infection symptoms in multiple sclerosis patients

Background

Patients with multiple sclerosis (MS) are at higher risk of having infections due to receiving disease modifying therapies. The current study was conducted among Iranian MS patients who had experienced at least one episode of COVID-19 infection in order to evaluate the effects of COVID-19 vaccination on symptoms of their infection. Data on demographic information, MS characteristics, COVID-19 infection details, and vaccination status were collected. Statistical analyses, were performed to evaluate the association between vaccination and symptoms of COVID-19 infection.

Methods

This cross-sectional study was conducted on confirmed MS patients. Demographic data and COVID-19 related symptoms were gathered via an online questionnaire. Confirmation of patients' who declared to be vaccinated was checked by their COVID-19 vaccination card.

Results

A total of 236 MS patients participated in the study. The majority were female (79.7%), with a mean age of 36.1 ± 7.9 years. Among the participants, 72.5% had received the COVID-19 vaccine before their first episode of COVID-19 infection. The analysis showed a significant difference in the incidence of respiratory symptoms (P-value: 0.01) and headache (P-value: 0.04) between vaccinated and non-vaccinated individuals. Logistic regression analysis revealed that vaccinated MS patients had lower odds of developing respiratory symptoms (OR:0.29, 95% CI: 0.16 to 0.53, P-value<0.001) or headache (OR: 0.50, 95% CI: 0.25 to 0.98, P-value: 0.04) during their next COVID-19 infection episode. Moreover, MS patients who were receiving immunosuppressive drugs were less likely to have respiratory symptoms (OR:0.35, 95% CI: 0.16 to 0.77, P-value:0.009) but not headache (OR: 0.69, 95% CI: 0.30 to 1.60, P-value: 0.39).

Conclusion

COVID-19 vaccination can reduce the incidence of respiratory symptoms and headaches in MS patients during COVID-19 infection episodes. Additionally, patients who are receiving immunosuppressive drugs may benefit from COVID-19 vaccination.

How could our genetics impact COVID-19 vaccine response?

INTRODUCTION

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has posed unprecedented global health challenges since its emergence in December 2019. The rapid availability of vaccines has been estimated to save millions of lives, but there is variation in how individuals respond to vaccines, influencing their effectiveness at an individual, and population level.

AREAS COVERED

This review focuses on human genetic factors influencing the immune response and effectiveness of vaccines, highlighting the importance of associations across the HLA locus. Genome-Wide Association Studies (GWAS) and other genetic association analyses have identified statistically significant associations between specific HLA alleles including HLA-DRB1*13, DBQ1*06, and A*03 impacting antibody responses and the risk of breakthrough infections post-vaccination. Relationships between these associations and potential mechanisms and links with risks of natural infection or disease are explored, and this review concludes by emphasizing how understanding the mechanisms of these genetic determinants may inform the development of tailored vaccination strategies.

EXPERT OPINION

Although complex, we believe these findings from the SARS-CoV2 pandemic offer a unique opportunity to understand the relationships between HLA and infection and vaccine response, with a goal of optimizing individual protection against COVID-19 in the ongoing pandemic, and possibly influencing wider vaccine development in the future.

Antiphospholipid syndrome in the era of COVID-19 - Two sides of a coin

In addition to the respiratory symptoms associated with COVID-19, the disease has consistently been linked to many autoimmune diseases such as systemic lupus erythematous and antiphospholipid syndrome (APS). APS in particular was of paramount significance due to its devastating clinical sequela. In fact, the hypercoagulable state seen in patients with acute COVID-19 and the critical role of anticoagulant treatment in affected individuals shed light on the possible relatedness between APS and COVID-19. Moreover, the role of autoimmunity in the assumed association is not less important especially with the accumulated data available regarding the autoimmunity-triggering effect of SARS-CoV-2 infection. This is furtherly strengthened at the time patients with COVID-19 manifested antiphospholipid antibodies of different types following infection. Additionally, the severe form of the APS spectrum, catastrophic APS (CAPS), was shown to have overlapping characteristics with severe COVID-19 such as cytokine storm and multi-organ failure. Interestingly, COVID vaccine-induced autoimmune phenomena described in the medical literature have pointed to an association with APS. Whether the antiphospholipid antibodies were present or de novo, COVID vaccine-induced vascular thrombosis in certain individuals necessitates further investigations regarding the possible mechanisms involved. In our current paper, we aimed to focus on the associations mentioned, their implications, importance, and consequences.

Diagnosis of COVID-19: Is Fever the Best Indicator of COVID-19 in Vaccinated SARS-CoV-2-Positive Adults?

OBJECTIVES

Coronavirus disease 2019 (COVID-19) vaccination is highly recommended to prevent the onset and severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Japan. However, the impact of COVID-19 vaccination on the manifestations or presenting symptoms of SARS-CoV-2 infection in daily clinical practice remains unclear.

METHODS

This retrospective single-center study was conducted from April 2021 to July 2022 in Japan. We compared the clinical manifestations of SARS-CoV-2 infection in 636 COVID-19-positive patients who visited our outpatient fever clinic, both COVID-19-vaccinated and unvaccinated.

RESULTS

During the study period, the COVID-19 vaccination rate at the time of infection was 77.2% (n=491/636), with a median of two doses. Most manifestations, including fever, were reduced in the vaccinated group (n=196) compared to the non-vaccinated group (n=142). The temperature at the clinic decreased significantly as the number of vaccinations increased. Fever was the most common manifestation in the non-vaccinated group (76%, n=108/142), while only 30% (n=59/196) of those who received three or more COVID-19 vaccinations experienced fever. However, sore throat and cough were observed more frequently in the vaccinated group compared to the non-vaccinated group.

CONCLUSION

Fever may not be a reliable indicator of SARS-CoV-2 infection in vaccinated individuals, as its frequency is significantly reduced by vaccination. However, since sore throat and cough are more frequently observed in vaccinated individuals, these symptoms could be useful for recommending COVID-19 testing even in the absence of fever, aiding in the prevention of infectious outbreaks.

Protection of Omicron Bivalent Vaccine, Previous Infection, and Their Induced Neutralizing Antibodies Against Symptomatic Infection With Omicron XBB.1.16 and EG.5.1

Background

Data are limited on the protective role of the Omicron BA bivalent vaccine, previous infection, and their induced neutralizing antibodies against Omicron XBB.1.16 and EG.5.1 infection.

Methods

We conducted a nested case-control analysis among tertiary hospital staff in Tokyo who had received ≥3 doses of COVID-19 vaccines and donated blood samples in June 2023 (1 month before the Omicron XBB.1.16 and EG.5.1 wave). We identified 206 symptomatic cases between June and September 2023 and selected their controls with 1:1 propensity score matching. We examined the association of vaccination, previous infection, and preinfection live virus neutralizing antibody titers against Omicron XBB.1.16 and EG.5.1 with the risk of COVID-19 infection.

Results

Previous infection during the Omicron BA- or XBB-dominant phase was associated with a significantly lower infection risk during the XBB.1.16 and EG.5.1-dominant phase than infection-naive status, with 70% and 100% protection, respectively, whereas Omicron BA bivalent vaccination showed no association. Preinfection neutralizing titers against XBB.1.16 and EG.5.1 were 39% (95% CI, 8%-60%) and 28% (95% CI, 8%-44%) lower in cases than matched controls. Neutralizing activity against XBB.1.16 and EG.5.1 was somewhat detectable in the sera of individuals with previous infection but barely detectable in those who were infection naive and received the Omicron bivalent vaccine.

Conclusions

In the era when the Omicron XBB vaccine was unavailable, the Omicron BA bivalent vaccine did not confer the neutralizing activity and protection against Omicron XBB.1.16 and EG.5.1 symptomatic infection. The previous infection afforded neutralizing titers and protection against symptomatic infection with these variants.

Engineering CaP-Pickering emulsion for enhanced mRNA cancer vaccines via dual DC and NK activations

mRNA delivery systems, such as lipid nanoparticle (LNP), have made remarkable strides in improving mRNA expression, whereas immune system activation operates on a threshold. Maintaining a delicate balance between antigen expression and dendritic cell (DC) activation is vital for effective immune recognition. Here, a water-in-oil-in-water (w/o/w) Pickering emulsion stabilized with calcium phosphate nanoparticles (CaP-PME) is developed for mRNA delivery in cancer vaccination. CaP-PME efficiently transports mRNA into the cytoplasm, induces pro-inflammatory responses and activates DCs by disrupting intracellular calcium/potassium ions balance. Unlike LNP, CaP-PME demonstrates a preference for DCs, enhancing their activation and migration to lymph nodes. It elicits interferon-γ-mediated CD8+ T cell responses and promotes NK cell proliferation and activation, leading to evident NK cells infiltration and ameliorated tumor microenvironment. The prepared w/o/w Pickering emulsion demonstrates superior anti-tumor effects in E.G7 and B16-OVA tumor models, offering promising prospects as an enhanced mRNA delivery vehicle for cancer vaccinations.

Gross Hematuria after the COVID-19 mRNA Vaccination: Nationwide Multicenter Prospective Cohort Study in Japan

Key Points

Little is known about the clinicopathological characteristics and renal outcomes in the patients with gross hematuria (GH) after the vaccination. To fill a clinicopathological knowledge gap regarding vaccination and GH, we conducted a nationwide multicenter prospective cohort study. GH is more likely to occur in patients with IgA nephropathy, with a female bias, but without progressive exacerbation of renal function.

Background

In the past 3 years, cases of gross hematuria (GH) after the vaccination for coronavirus disease 2019 in patients with IgA nephropathy (IgAN) have been frequently reported worldwide. However, the postevent renal prognosis of these patients, their clinical backgrounds, and underlying mechanisms remain unknown. Therefore, we conducted a nationwide multicenter prospective cohort study in Japan.

Methods

We analyzed laboratory findings at the time of the first presentation to the hospital and 3 and 6 months after in patients with GH after the vaccination and histopathological findings in their kidney biopsy specimens. Moreover, changes in pathological biomarkers of IgAN such as galactose-deficient IgA1 (Gd-IgA1) and its immune complexes were also evaluated.

Results

During the study period, 127 newly presenting patients with GH after the vaccination were enrolled, with a clear female bias (73.2%). GH was observed after the second or subsequent vaccinations in most patients (92.9%). Of the 37 patients undergoing kidney biopsy before the vaccination, 36 patients had been diagnosed with IgAN/IgA vasculitis (IgAV). In the remaining 90 patients, 69 of the 70 who newly underwent kidney biopsy were diagnosed with IgAN (n =67)/IgAV (n =2). Their histopathology did not show a high incidence of acute lesions such as endocapillary hypercellularity and crescentic lesions. Most cases showed a temporary increase in proteinuria, but no sustained worsening in renal function. Among the biomarkers measured, serum Gd-IgA1 and immune complexes were comparable throughout the observation period; however, only urinary Gd-IgA1 was increased at the time of GH.

Conclusions

We found that GH after the vaccination is more likely to occur in patients with IgAN/IgAV, with a female bias, but without progressive exacerbation of renal function. Although further investigation is needed regarding causal relationship between vaccination and GH, this study provides many insights into the molecular mechanisms of GH.

Insights into the formulation of lipid nanoparticles for the optimization of mRNA therapeutics

mRNA-based therapeutics increasingly demonstrate significant potential in treating various diseases, including infectious diseases, cancers, and genetic disorders. Effective delivery systems are crucial for advancing mRNA therapeutics. Lipid nanoparticles (LNPs) serve as an excellent carrier, widely validated for their safety and tolerability in commercially available mRNA vaccines. Standard LNPs typically consist of four components: ionizable lipids (ILs), helper lipids, cholesterol, and polyethylene glycol-lipids (PEG-lipids), with the structural design of ILs gradually becoming a focal point of research interest. The chemical structures and formulations of the other components also significantly affect the delivery efficiency, targeting specificity, and stability of LNPs. The complex formulations of LNPs may hinder the clinical transformation of mRNA therapeutics and have raised widespread concerns about their safety. This review aims to summarize the progress of LNPs-based mRNA therapeutics in clinical trials, focusing on adverse effects that occurred during these trials. It also discusses representative innovations in LNP components, highlighting challenges and potential ways in this research field. We firmly believe this review will promote further improvements and designs of LNP compositions to optimize mRNA therapeutics. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Biology-Inspired Nanomaterials > Lipid-Based Structures.

Preformed Vesicle Approach to LNP Manufacturing Enhances Retinal mRNA Delivery

Complete encapsulation of nucleic acids by lipid-based nanoparticles (LNPs) is often thought to be one of the main prerequisites for successful nucleic acid delivery, as the lipid environment protects mRNA from degradation by external nucleases and assists in initiating delivery processes. However, delivery of mRNA via a preformed vesicle approach (PFV-LNPs) defies this precondition. Unlike traditional LNPs, PFV-LNPs are formed via a solvent-free mixing process, leading to a superficial mRNA localization. While demonstrating low encapsulation efficiency in the RiboGreen assay, PFV-LNPs improved delivery of mRNA to the retina by up to 50% compared to the LNP analogs across several benchmark formulations, suggesting the utility of this approach regardless of the lipid composition. Successful mRNA and gene editors' delivery is observed in the retinal pigment epithelium and photoreceptors and validated in mice, non-human primates, and human retinal organoids. Deploying PFV-LNPs in gene editing experiments result in a similar extent of gene editing compared to analogous LNP (up to 3% on genomic level) in the Ai9 reporter mouse model; but, remarkably, retinal tolerability is significantly improved for PFV-LNP treatment. The study findings indicate that the LNP formulation process can greatly influence mRNA transfection and gene editing outcomes, improving LNP treatment safety without sacrificing efficacy.

Novel Administration Routes, Delivery Vectors, and Application of Vaccines Based on Biotechnologies: A Review

Traditional vaccines can be classified into inactivated vaccines, live attenuated vaccines, and subunit vaccines given orally or via intramuscular (IM) injection or subcutaneous (SC) injection for the prevention of infectious diseases. Recently, recombinant protein vaccines, DNA vaccines, mRNA vaccines, and multiple/alternative administering route vaccines (e.g., microneedle or inhalation) have been developed to make vaccines more secure, effective, tolerable, and universal for the public. In addition to preventing infectious diseases, novel vaccines have currently been developed or are being developed to prevent or cure noninfectious diseases, including cancer. These vaccine platforms have been developed using various biotechnologies such as viral vectors, nanoparticles, mRNA, recombination DNA, subunit, novel adjuvants, and other vaccine delivery systems. In this review, we will explore the development of novel vaccines applying biotechnologies, such as vaccines based on novel administration routes, vaccines based on novel vectors, including viruses and nanoparticles, vaccines applied for cancer prevention, and therapeutic vaccines.

Perceptions and acceptance of COVID-19 vaccine among pregnant and lactating women in Singapore: a pre-vaccine rollout cross-sectional study

INTRODUCTION

Vaccination is critical in controlling the coronavirus disease 2019 (COVID-19) pandemic. However, vaccine perception and acceptance among pregnant and lactating women is unknown in Singapore. We aimed to determine the acceptance of COVID-19 vaccination among these two groups of women in Singapore and the factors associated with vaccine acceptance.

METHODS

We conducted an anonymous, online survey on the perceptions of the COVID-19 vaccine and its acceptance by pregnant and lactating women at a tertiary maternal and child hospital in Singapore from 1 March to 31 May 2021. Information on their demographics and knowledge was collected. These factors were assessed for their relationship with vaccine acceptance.

RESULTS

A total of 201 pregnant and 207 lactating women participated. Vaccine acceptance rates in pregnant and lactating women were 30.3% and 16.9%, respectively. Pregnant women who were unsure or unwilling to take the vaccine cited concerns about safety of the vaccine during pregnancy (92.9%), while lactating women were concerned about its potential long-term negative effects on the breastfeeding child (75.6%). Factors that were positively associated with vaccine acceptance included a lower monthly household income or education level, appropriate knowledge regarding vaccine mechanism and higher perceived maternal risk of COVID-19. Most pregnant (70.0%) and lactating women (83.7%) were willing to take the vaccine only when more safety data during pregnancy and breastfeeding were available.

CONCLUSION

COVID-19 vaccine acceptance was low among pregnant and lactating women in Singapore. Addressing the safety concerns when more data are available and education on the mechanism of vaccine action will likely improve acceptance among these women.

XBB.1.16-RBD-based trimeric protein vaccine can effectively inhibit XBB.1.16-included XBB subvariant infection

The newly identified XBB.1.16-containing sublineages, including XBB.1.5, have become the prevailing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant in circulation. Unlike previous Omicron XBB variants (e.g., XBB.1.5 and XBB.1.9) harboring the F486P substitution, XBB.1.16 also carries a T478R substitution in the receptor-binding domain (RBD). Numerous researchers have delved into the high transmissibility and immune evasion of XBB.1.16 subvariant. Therefore, developing a new vaccine targeting XBB.1.16, including variants of concern (VOCs), is paramount. In our study, we engineered a recombinant protein by directly linking the S-RBD sequence of the XBB.1.16 strain of SARS-CoV-2 to the sequences of two heptad repeat sequences (HR1 and HR2) from the SARS-CoV-2 S2 subunit. Named the recombinant RBDXBB.1.16-HR/trimeric protein, this fusion protein autonomously assembles into a trimer. Combined with an MF59-like adjuvant, the RBDXBB.1.16-HR vaccine induces a robust humoral immune response characterized by high titers of neutralizing antibodies against variant pseudovirus and authentic VOCs and cellular immune responses. Additionally, a fourth heterologous RBDXBB.1.16-HR vaccine enhances both humoral and cellular immune response elicited by three-dose mRNA vaccines. These findings demonstrate that the recombinant RBDXBB.1.16-HR protein, featuring the new T478R mutation, effectively induces solid neutralizing antibodies to combat newly emerged XBB variants.

A perspective on bleb and empty LNP structures

Although lipid nanoparticles (LNPs) have been FDA-approved for mRNA delivery, there is still much to learn about these fascinating multi-component delivery systems. Here, I discuss the presence of "bleb" structures on LNPs and the co-existence of mRNA-empty LNPs in LNP-mRNA-based formulations. Specifically, I discuss key articles on these structural and compositional heterogeneities, whether these features present negative or positive LNP attributes, and how to deal with them in research and quality control settings. Additionally, I present current approaches and propose novel strategies on how to study and quantify bleb and empty LNP structures. With the conflicting views on these features in the literature and limited systematic studies on their impact on safety and efficacy, I hope this Perspective will support current and bring forward new thinking about these matters. I anticipate that novel studies and insights could emerge from these lines of thinking, which could potentially enhance the development of safe and efficient LNP-based drug products that will either embrace, leverage, or mitigate the presence of blebs and empty LNPs.

Modeling of anti-spike IgG and neutralizing antibody waning after anti-SARS-CoV-2 mRNA vaccination

At present, mRNA-based vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being administered on a global scale. While the efficacy of mRNA vaccines has been demonstrated, several unknowns remains. For example, as the number of booster vaccinations increases, there are uncertainties regarding how long effects of a vaccine will last and how much individual variability exists. In this study, to predict the duration of vaccine efficacy, we modeled the kinetics of antibody levels for each SARS-CoV-2 vaccination dose, incorporating predictive intervals to estimate the duration of vaccine efficacy and to account for variability among individuals. A total of 3,059 serum samples from 1,346 participants were assayed to quantify IgG antibodies specific for the S1 subunit of the S protein (anti-S1 IgG) and neutralizing antibody activities against SARS-CoV-2. A power law model was used to simulate the decay of antibody titers following vaccination, and models were constructed to assess antibody level kinetics after the second, third, fourth, and fifth vaccinations. The models assumed that booster vaccinations would significantly reduce the decline in anti-S antibody and neutralizing antibody levels, resulting in levels being maintained for a longer period. No significant differences in the decay rate of antibody levels were observed among age groups, yet the peak titers of antibody levels were significantly higher in the ≤ 39 age group than in the ≥ 60 age group following the second vaccination; these differences were not observed after the third and fourth vaccinations. The modeling of antibody level kinetics after vaccination is considered to be useful for understanding the immune status of mRNA vaccine recipients.

Vaccine-induced humoral response of BNT162b2 and mRNA-1273 against BA.1, BA.5, and XBB.1.5. (sub)variants 6 months after a homologous booster: is immunogenicity equivalent?

Introduction

Some studies suggest that the monovalent mRNA-1273 vaccine is more effective than BNT162b2 in producing higher levels of antibodies. However, limited data are available, and the methods used are not directly comparable.

Material and methods

Blood samples were obtained before the booster (third dose) and after 14, 90, and 180 days in two similar cohorts who received the original BNT162b2 or mRNA-1273 vaccine designed to target wild type SARS-CoV-2. The aim of our study is to compare their effectiveness by assessing the levels of binding and neutralizing antibodies specifically against each of the BA.1 variant, BA.5 variant, and the XBB.1.5 subvariant.

Results

Once the peak was reached after two weeks, a drastic decline in binding and neutralizing antibodies was observed up to 6 months after the homologous booster administration. The humoral response was however more sustained with the mRNA-1273 booster, with half-lives of 167, 55, and 48 days for binding, BA.1, and BA.5 neutralizing antibodies compared to 144, 30, and 29 days for the BNT162b2 booster, respectively. Compared to the BA.1 variant, the neutralizing capacity was significantly decreased at 6 months with the BA.5 variant (fold-decrease: 1.67 to 3.20) and the XBB.1.5. subvariant (fold-decrease: 2.86 to 5.48).

Conclusion

Although the decrease in the humoral response was observed with both mRNA vaccines over time, a more sustained response was observed with the mRNA-1273 vaccine. Moreover, the emergence of Omicron-based variants causes a reduced neutralizing capacity, notably with the XBB.1.5. subvariant. The administration of subsequent boosters would therefore be needed to restore a sufficiently high neutralizing response.

Post-Hoc Analysis of Potential Correlates of Protection of a Recombinant SARS-CoV-2 Spike Protein Extracellular Domain Vaccine Formulated with Advax-CpG55.2-Adjuvant

SpikoGen® vaccine is a subunit COVID-19 vaccine composed of an insect cell expressed recombinant spike protein extracellular domain formulated with Advax-CpG55.2™ adjuvant. A randomized double-blind, placebo-controlled Phase II clinical trial was conducted in 400 adult subjects who were randomized 3:1 to receive two intramuscular doses three weeks apart of either SpikoGen® vaccine 25 μg or saline placebo, as previously reported. This study reports a post hoc analysis of the trial data to explore potential immune correlates of SpikoGen® vaccine protection. A range of humoral markers collected pre- and post-vaccination, including spike- and RBD-binding IgG and IgA, surrogate (sVNT), and conventional (cVNT) virus neutralization tests were compared between participants who remained infection-free or got infected over three months of follow-up. From 2 weeks after the second vaccine dose, 21 participants were diagnosed with SARS-CoV-2 infection, 13 (4.2%) in the SpikoGen® group and 8 (9%) in the placebo group. Those in the vaccinated group who experienced breakthrough infections had significantly lower sVNT titers (GMT 5.75 μg/mL, 95% CI; 3.72-8.91) two weeks after the second dose (day 35) than those who did not get infected (GMT 21.06 μg/mL, 95% CI; 16.57-26.76). Conversely, those who did not develop SARS-CoV-2 infection during follow-up had significantly higher baseline sVNT, cVNT, spike-binding IgG and IgA, and RBD-binding IgG, consistent with a past SARS-CoV-2 infection. SpikoGen® further reduced the risk of re-infection (OR 0.29) in baseline seropositive (previously infected) as well as baseline seronegative participants. This indicates that while SpikoGen vaccine is protective in seronegative individuals, those with hybrid immunity have the most robust protection.

Investigating the influencing factors of vaccination decisions for newly developed and established vaccines: a comparative study based on latent class logit models in China

Background

The factors influencing vaccination decision-making for newly developed vaccines may be similar to and different from those for established vaccines. Understanding these underlying differences and similarities is crucial for designing targeted measures to promote new vaccines against potential novel viruses.

Objective

This study aims to compare public vaccination decisions for newly developed and established vaccines and to identify the differences and similarities in the influencing factors.

Method

A discrete choice experiment (DCE) was conducted on 1,509 representatives of the general population in China to collect data on preferences for the coronavirus disease 2019 (COVID-19) and influenza vaccines, representing the newly developed and established vaccines, respectively. The latent class logit model was used to identify latent classes within the sample, allowing for an analysis of the factors distinctly influencing choices for both types of vaccines.

Result

Participants valued similar attributes for both vaccines. However, concerns about sequelae were more significant for the newly developed vaccine, while effectiveness was prioritized for the established vaccine. Class membership analysis revealed these differences and similarities were significantly correlated with age, health, yearly household income, acquaintances' vaccination status, and risk perception.

Conclusion

The study highlights the need for tailored communication strategies and targeted vaccination interventions. For the newly developed vaccines, addressing concerns about side effects is more crucial. For long-standing vaccines, emphasizing their effectiveness can enhance uptake more significantly. Engaging healthcare providers and community influencers is essential for both vaccines to increase public confidence and vaccination rates. Clear communication and community engagement are critical strategies for addressing public concerns and misinformation, particularly during periods of heightened concern.

Long-term safety and effectiveness of mRNA-1273 vaccine in adults: COVE trial open-label and booster phases

Primary vaccination with mRNA-1273 (100-µg) was safe and efficacious at preventing coronavirus disease 2019 (COVID-19) in the previously reported, blinded Part A of the phase 3 Coronavirus Efficacy (COVE; NCT04470427) trial in adults (≥18 years) across 99 U.S. sites. The open-label (Parts B and C) primary objectives were evaluation of long-term safety and effectiveness of primary vaccination plus a 50-µg booster dose; immunogenicity was a secondary objective. Of 29,035 open-label participants, 19,609 received boosters (mRNA-1273 [n = 9647]; placebo-mRNA-1273 [n = 9952]; placebo [n = 10] groups). Booster safety was consistent with that reported for primary vaccination. Incidences of COVID-19 and severe COVID-19 were higher during the Omicron BA.1 than Delta variant waves and boosting versus non-boosting was associated with a significant, 47.0% (95% CI : 39.0-53.9%) reduction of Omicron BA.1 incidence (24.6 [23.4 - 25.8] vs 46.4 [40.6 - 52.7]/1000 person-months). In an exploratory Cox regression model adjusted for time-varying covariates, a longer median interval between primary vaccination and boosting (mRNA-1273 [13 months] vs placebo-mRNA-1273 [8 months]) was associated with significantly lower, COVID-19 risk (24.0% [16.0% - 32.0%]) during Omicron BA.1 predominance. Boosting elicited greater immune responses against SARS-CoV-2 than primary vaccination, irrespective of prior SARS-CoV-2 infection. Primary vaccination and boosting with mRNA-1273 demonstrated acceptable safety, effectiveness and immunogenicity against COVID-19, including emergent variants.

SARS-CoV-2 Evolution: Immune Dynamics, Omicron Specificity, and Predictive Modeling in Vaccinated Populations

Host immunity is central to the virus's spread dynamics, which is significantly influenced by vaccination and prior infection experiences. In this work, we analyzed the co-evolution of SARS-CoV-2 mutation, angiotensin-converting enzyme 2 (ACE2) receptor binding, and neutralizing antibody (NAb) responses across various variants in 822 human and mice vaccinated with different non-Omicron and Omicron vaccines is analyzed. The link between vaccine efficacy and vaccine type, dosing, and post-vaccination duration is revealed. The classification of immune protection against non-Omicron and Omicron variants is co-evolved with genetic mutations and vaccination. Additionally, a model, the Prevalence Score (P-Score) is introduced, which surpasses previous algorithm-based models in predicting the potential prevalence of new variants in vaccinated populations. The hybrid vaccination combining the wild-type (WT) inactivated vaccine with the Omicron BA.4/5 mRNA vaccine may provide broad protection against both non-Omicron variants and Omicron variants, albeit with EG.5.1 still posing a risk. In conclusion, these findings enhance understanding of population immunity variations and provide valuable insights for future vaccine development and public health strategies.

Effect of COVID 19 pandemic on the neurology department hospitalization with analysis of the neurological complications secondary to COVID 19 and vaccination against COVID 19

Objective

We investigated the effect of the pandemic on neurological hospitalizations and complications associated with severe acute respiratory syndrome coronavirus 2 infection or vaccinations.

Methods

We retrospectively analyzed data of patients hospitalized in our neurology division from 1 April 2019 to 31 March 2022 as the opt-out study. We classified the neurological diseases into nine subgroups, evaluated changes of neurological disease characteristics, and analyzed patients hospitalized with the complications from severe acute respiratory syndrome coronavirus 2 infection or after the coronavirus disease 2019 vaccination over three eras based on the pandemic stages: (1) pre-pandemic, (2) during the pandemic but before vaccines, and (3) during the pandemic with vaccines.

Results

Overall, 1756 patients were included in the analyses. The patient characteristics significantly changed throughout the pandemic (p < 0.01). Although the number of autoimmune cases did not change throughout the pandemic (p = 0.53), that of psychological cases and that of unknown cases were significantly changed (p < 0.05, p < 0.01). There were four infectious cases and 11 cases following vaccination from 1 April 2020 to 31 March 2022. The 11 postvaccination cases involved 10 kinds of neurological diseases.

Conclusions

The neurological characteristics significantly changed throughout the pandemic and there were diverse neurological complications following vaccinations.

Bactofection, Bacterial-Mediated Vaccination, and Cancer Therapy: Current Applications and Future Perspectives

From the first report in 1891 by Dr. Coley of the effective treatment of tumors in 1000 patients with Streptococcus and the first successful use of bacterial vectors for transferring therapeutic genes in 1980 by Dr. Schnaffer, bactofection has been shown to be a promising strategy in the fields of vaccination, gene therapy, and cancer therapy. This review describes the general theory of bactofection and its advantages, disadvantages, challenges, and expectations, compiling the most notable advances in 14 vaccination studies, 27 cancer therapy studies, and 13 clinical trials. It also describes the current scope of bactofection and promising results. The extensive knowledge of Salmonella biology, as well as the multiple adequacies of the Ty21a vaccination platform, has allowed notable developments worldwide that have mainly been reflected in therapeutic efforts against cancer. In this regard, we strongly recommend the creation of a recombinant Ty21a model that constitutively expresses the GtgE protease from S. typhimurium, allowing this vector to be used in animal trials, thus enhancing the likelihood of favorable results that could quickly transition to clinical trials. From the current perspective, it is necessary to explore a greater diversity of bacterial vectors and find the best combination of implemented attenuations, generating personalized models that guarantee the maximum effectiveness in cancer therapy and vaccination.

Innate immune responses against mRNA vaccine promote cellular immunity through IFN-β at the injection site

mRNA vaccines against SARS-CoV-2 have revolutionized vaccine development, but their immunological mechanisms are not fully understood. Here, we investigate injection site responses of mRNA vaccines by generating a comprehensive single-cell transcriptome profile upon lipid nanoparticle (LNP) or LNP-mRNA challenge in female BALB/c mice. We show that LNP-induced stromal pro-inflammatory responses and mRNA-elicited type I interferon responses dominate the initial injection site responses. By tracking the fate of delivered mRNA, we discover that injection site fibroblasts are highly enriched with the delivered mRNA and that they express IFN-β specifically in response to the mRNA component, not to the LNP component of mRNA vaccines. Moreover, the mRNA-LNP, but not LNP alone, induces migratory dendritic cells highly expressing IFN-stimulated genes (mDC_ISGs) at the injection site and draining lymph nodes. When co-injected with LNP-subunit vaccine, IFN-β induces mDC_ISGs at the injection site, and importantly, it substantially enhances antigen-specific cellular immune responses. Furthermore, blocking IFN-β signaling at the injection site significantly decreases mRNA vaccine-induced cellular immune responses. Collectively, these data highlight the importance of injection site fibroblasts and IFN-β signaling during early immune responses against the mRNA vaccine and provide detailed information on the initial chain of immune reactions elicited by mRNA vaccine injection.

Short-Term Active Safety Surveillance of the Spikevax and Nuvaxovid Priming Doses in Australia

Australia commenced administration of the Spikevax (Moderna mRNA-1273) COVID-19 vaccine in August 2021 and Nuvaxovid (Novavax NVX-CoV2373) in January 2022. This study describes the short-term safety profile of priming doses of the Spikevax and Nuvaxovid vaccines given between September 2021 and September 2023. Online surveys were sent via AusVaxSafety, Australia's active vaccine safety surveillance system, three and eight days after vaccination. A total of 131,775 day 3 surveys were sent, with a response rate of 38.5% (N = 50,721). A total of 43,875 day 8 surveys matched with day 3 survey responses were sent, with a response rate of 71.5% (N = 31,355). Half (50.7%) of respondents reported any adverse event following immunisation (AEFI) in the 0-3 days after vaccination and 24.6% reported any AEFI 4-7 days after vaccination. Fatigue, local pain, headache, and myalgia were the most frequently reported symptoms for both vaccines in both periods. After adjusting for respondent characteristics, vaccination clinic type, jurisdiction, and medical conditions, the odds for reporting AEFI increased with age from 16-19 years to highest odds at 30-39 years, after which it declined. Females had greater odd of reporting AEFI than males across most age groups, vaccine types, and doses. Respondents with a history of anaphylaxis had greater odds of reporting any AEFI (adjusted OR range: 1.50-2.86). A total of 3.1% of respondents reported seeking medical review 0-3 days after vaccination. This study affirms the short-term safety of Spikevax and Nuvaxovid COVID-19 vaccine priming doses in a large sample in Australia.

Optimization of the 5' untranslated region of mRNA vaccines

To investigate the impact of different 5' untranslated regions (UTRs) on mRNA vaccine translation efficiency, five dual-reporter gene expression plasmids with different 5'UTRs were constructed. The corresponding mRNA transcripts were transcribed and capped in vitro. By comparing the expression levels of reporter genes with different 5'UTRs, we identified the 5'UTR associated with the highest expression level. Subsequently, HIVgp145 mRNA vaccines containing various 5'UTRs were constructed and verified. The results demonstrated that mRNA 3 (β-globin 5'UTR) displayed the greatest number of green fluorescence-positive cells and the highest luciferase fluorescence intensity in the reporter gene expression system. Further, among the HIVgp145 mRNA vaccines with different 5'UTRs, mRNA 7 (β-globin 5'UTR) exhibited the highest level of expression. These findings indicate that it is feasible to use the 5'UTR of β-globin in an mRNA vaccine, laying the foundation for animal immunogenicity testing.

Design, Immunogenicity and Preclinical Efficacy of the ChAdOx1.COVconsv12 Pan-Sarbecovirus T-Cell Vaccine

During the COVID-19 pandemic, antibody-based vaccines targeting the SARS-CoV-2 spike glycoprotein were the focus for development because neutralizing antibodies were associated with protection against the SARS-CoV-2 infection pre-clinically and in humans. While deploying these spike-based vaccines saved millions of lives worldwide, it has become clear that the immunological mechanisms of protection against severe disease are multifaceted and involve non-neutralizing antibody components. Here, we describe a novel pan-sarbecovirus T-cell vaccine, ChAdOx1.COVconsv12, designed to complement and broaden the protection of spike vaccines. The vaccine immunogen COVconsv12 employs the two regions in the viral proteome most conserved among sarbecoviruses, which are delivered by replication-deficient vector ChAdOx1. It directs T cells towards epitopes shared among sarbecoviruses including evolving SARS-CoV-2 variants. Here, we show that ChAdOx1.COVconsv12 induced broad T-cell responses in the BALB/c and C57BL/6 mice. In the Syrian hamster challenge model, ChAdOx1.COVconsv12 alone did not protect against the SARS-CoV-2 infection, but when co-administered with 1/50th of the ChAdOx1 nCoV-19 spike vaccine protective dose, faster recovery and lower oral swab viral load were observed. Induction of CD8+ T cells may decrease COVID-19 severity and extend the T-cell response coverage of variants to match the known (and as yet unknown) members of the β-coronavirus family.

Evaluation of inflammatory biomarkers and their association with anti-SARS-CoV-2 antibody titers in healthcare workers vaccinated with BNT162B2

Introduction

Vaccine-induced immunity against COVID-19 generates antibody and lymphocyte responses. However, variability in antibody titers has been observed after vaccination, and the determinants of a better response should be studied. The main objective of this investigation was to analyze the inflammatory biomarker response induced in healthcare workers vaccinated with BNT162b2, and its association with anti-Spike (a SARS-CoV-2 antigen) antibodies measured throughout a 1-year follow-up.

Methods

Anti-spike antibodies and 92 biomarkers were analyzed in serum, along with socio-demographic and clinical variables collected by interview or exploration.

Results

In our study, four biomarkers (ADA, IL-17C, CCL25 and CD8α) increased their expression after the first vaccine dose; and 8 others (uPA, IL-18R1, EN-RAGE, CASP-8, MCP-2, TNFβ, CD5 and CXCL10) decreased their expression. Age, body mass index (BMI), smoking, alcohol consumption, and prevalent diseases were associated with some of these biomarkers. Furthermore, higher baseline levels of T-cell surface glycoprotein CD6 and hepatocyte growth factor (HGF) were associated with lower mean antibody titers at follow-up, while levels of monocyte chemotactic protein 2 (MCP-2) had a positive association with antibody levels. Age and BMI were positively related to baseline levels of MCP-2 (β=0.02, 95%CI 0.00-0.04, p=0.036) and HGF (β=0.03, 95%CI 0.00-0.06, p=0.039), respectively.

Conclusion

Our findings indicate that primary BNT162b2 vaccination had a positive effect on the levels of several biomarkers related to T cell function, and a negative one on some others related to cancer or inflammatory processes. In addition, a higher level of MCP-2 and lower levels of HGF and CD6 were found to be associated with higher anti-Spike antibody titer following vaccination.

Advances in the study of LNPs for mRNA delivery and clinical applications

Messenger ribonucleic acid (mRNA) was discovered in 1961 as an intermediary for transferring genetic information from DNA to ribosomes for protein synthesis. The COVID-19 pandemic brought worldwide attention to mRNA vaccines. The emergency use authorization of two COVID-19 mRNA vaccines, BNT162b2 and mRNA-1273, were major achievements in the history of vaccine development. Lipid nanoparticles (LNPs), one of the most superior non-viral delivery vectors available, have made many exciting advances in clinical translation as part of the COVID-19 vaccine and therefore has the potential to accelerate the clinical translation of many gene drugs. In addition, due to these small size, biocompatibility and excellent biodegradability, LNPs can efficiently deliver nucleic acids into cells, which is particularly important for current mRNA therapeutic regimens. LNPs are composed cationic or pH-dependent ionizable lipid bilayer, polyethylene glycol (PEG), phospholipids, and cholesterol, represents an advanced system for the delivery of mRNA vaccines. Furthermore, optimization of these four components constituting the LNPs have demonstrated enhanced vaccine efficacy and diminished adverse effects. The incorporation of biodegradable lipids enhance the biocompatibility of LNPs, thereby improving its potential as an efficacious therapeutic approach for a wide range of challenging and intricate diseases, encompassing infectious diseases, liver disorders, cancer, cardiovascular diseases, cerebrovascular conditions, among others. Consequently, this review aims to furnish the scientific community with the most up-to-date information regarding mRNA vaccines and LNP delivery systems.

COVID-19 Vaccination and Ocular Adverse Events: A Self-Controlled Case Series Study From the Entire South Korean Population

PURPOSE

This study aimed to assess the risk of ocular adverse events, including retinal artery occlusion (RAO), retinal vein occlusion (RVO), noninfectious uveitis (NIU), noninfectious scleritis (NIS), optic neuritis (ON), ischemic optic neuropathy (ION), and ocular motor cranial nerve palsy (OMCNP), following Coronavirus Disease 2019 (COVID-19) vaccination.

DESIGN

Population-based self-controlled case series METHODS: This study utilized nationwide claims and vaccination data provided by the Korea National Health Insurance Service and Korea Disease Control and Prevention Agency. From the entire South Korean population of 52 million individuals, patients with incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP between January 2021 and March 2022 were included. The postvaccination risk period was defined as up to 56 days after COVID-19 vaccination. The relative incidence rate ratios (IRRs) for RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP during the risk periods were measured using conditional Poisson regression.

RESULTS

The study included 6,590, 70,120, 137,958, 17,921, 15,492, 2,039, 49,089, and 11,312 cases of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP, respectively. The IRRs (95% confidence interval) during the early risk period (0-28 days) were 0.95 (0.88-1.01), 0.96 (0.94-0.98), 0.93 (0.91-0.94), 0.93 (0.89-0.96), 0.96 (0.92-1.01), 1.04 (0.92-1.18), 0.98 (0.95-1.00), and 0.91 (0.86-0.96), respectively. In the late risk period (29-56 days), the IRRs were 0.96 (0.89-1.03), 0.93 (0.91-0.96), 0.96 (0.95-0.98), 1.00 (0.95-1.04), 0.96 (0.91-1.01), 1.00 (0.87-1.15), 1.01 (0.98-1.04), and 0.95 (0.90-1.01), respectively.

CONCLUSION

COVID-19 vaccination did not increase the risk of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP during the postvaccination period.

Vaccines for Respiratory Viruses-COVID and Beyond

The COVID-19 (coronavirus disease 2019) pandemic had an extensive impact on global morbidity and mortality. Several other common respiratory viruses, such as the influenza virus and respiratory syncytial virus (RSV), are endemic or epidemic agents causing acute respiratory infections that are easily transmissible and pose a significant threat to communities due to efficient person-to-person transmission. These viruses can undergo antigenic variation through genetic mutations, resulting in the emergence of novel strains or variants, thereby diminishing the effectiveness of current vaccines, and necessitating ongoing monitoring and adjustment of vaccine antigens. As the virus-specific immunity is maintained only for several weeks or months after the infection, there is an emergent need to develop effective and durable vaccines. Additionally, specific populations, such as elderly or immunocompromised individuals, may exhibit reduced immune responses to respiratory viruses, posing significant challenges to develop vaccines that elicit durable and potent immunity. We present a comprehensive review of the molecular mechanisms underlying the pathogenesis and virulence of common respiratory viruses, such as RSV, influenza virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We discuss several vaccine approaches that are under development. A thorough understanding of the current strategies and the challenges encountered during the vaccine development process can lead to the advancement of effective next-generation vaccines.

Thromboembolism after coronavirus disease 2019 vaccination in atrial fibrillation/flutter: a self-controlled case series study

BACKGROUND AND AIMS

Concerns about the safety of coronavirus disease 2019 (COVID-19) vaccines in patients with atrial fibrillation/flutter (AF/AFL) have arisen due to reports of thrombo-embolic events following COVID-19 vaccination in the general population. This study aimed to evaluate the risk of thrombo-embolic events after COVID-19 vaccination in patients with AF/AFL.

METHODS

This was a modified self-controlled case-series study using a comprehensive nationwide-linked database provided by the National Health Insurance Service in South Korea to calculate incidence rate ratios (IRRs) of thrombo-embolic events. The study population included individuals aged ≥12 years who were either vaccinated (e.g. one or two doses) or unvaccinated during the period from February to December 2021. The primary outcome was a composite of thrombo-embolic events, including ischaemic stroke, transient ischaemic attack, and systemic thromboembolism. The risk period was defined as 0-21 days following COVID-19 vaccination.

RESULTS

The final analysis included 124 127 individuals with AF/AFL. The IRR of thrombo-embolic events within 21 days after COVID-19 vaccination, compared with that during the unexposed control period, was 0.93 [95% confidence interval (CI) 0.77-1.12]. No significant risk variations were noted by sex, age, or vaccine type. However, patients without anticoagulant therapy had an IRR of 1.88 (95% CI 1.39-2.54) following vaccination.

CONCLUSIONS

In patients with AF/AFL, COVID-19 vaccination was generally not associated with an increased risk of thrombo-embolic events. However, careful individual risk assessment is required when advising vaccination for those not on oral anticoagulant, as these patients exhibited an increased risk of thrombo-embolic events post-vaccination.

Repeated Omicron exposures redirect SARS-CoV-2-specific memory B cell evolution toward the latest variants

Immunological imprinting by ancestral SARS-CoV-2 strains is thought to impede the robust induction of Omicron-specific humoral responses by Omicron-based booster vaccines. Here, we analyzed the specificity and neutralization activity of memory B (Bmem) cells after repeated BA.5 exposure in individuals previously imprinted by ancestral strain-based mRNA vaccines. After a second BA.5 exposure, Bmem cells with BA.5 spike protein-skewed reactivity were promptly elicited, correlating with preexisting antibody titers. Clonal lineage analysis identified BA.5-skewed Bmem cells that had redirected their specificity from the ancestral strain to BA.5 through somatic hypermutations. Moreover, Bmem cells with redirected BA.5 specificity exhibited accelerated development compared with de novo Bmem cells derived from naïve repertoires. This redirected BA.5 specificity demonstrated greater resilience to viral point mutation and adaptation to recent Omicron variants HK.3 and JN.1, months after the second BA.5 exposure, suggesting that existing Bmem cells elicited by older vaccines can redirect their specificity toward newly evolving variants.

Enhancing Vaccine Efficacy and Stability: A Review of the Utilization of Nanoparticles in mRNA Vaccines

The development of vaccines has entered a new era with the advent of nanotechnology, particularly through the utilization of nanoparticles. This review focuses on the role of nanoparticles in enhancing the efficacy and stability of mRNA vaccines. Nanoparticles, owing to their unique properties such as high surface area, tunable size, and their ability to be functionalized, have emerged as powerful tools in vaccine development. Specifically, lipid nanoparticles (LNPs) have revolutionized the delivery of mRNA vaccines by protecting the fragile mRNA molecules and facilitating their efficient uptake by cells. This review discusses the various types of nanoparticles employed in mRNA vaccine formulations, including lipid-based, polymer-based, and inorganic nanoparticles, highlighting their advantages and limitations. Moreover, it explores the mechanisms by which nanoparticles improve immune responses, such as enhanced antigen presentation and the prolonged release of mRNA. This review also addresses the challenges and future directions in nanoparticle-based vaccine development, emphasizing the need for further research to optimize formulations for broader applications. By providing an in-depth analysis of the current advancements in and potential of nanoparticles in mRNA vaccines, this review aims to shed light on their critical role in combating infectious diseases and improving public health outcomes.

Evaluation of the COVID-19 vaccine effectiveness on the outcomes of COVID 19 disease in Iran: a test-negative case-control study

Introduction

This study measures the COVID-19 vaccine effectiveness (CVE) against hospital admission and severe COVID-19.

Methods

This study is a test-negative case-control design using data from eight provinces in April, 2021 until March, 2022. The individuals were classified as cases and controls based on the results of the RT-PCR test for SARS-CoV-2 and matched based on the timing of the test being conducted as well as the timing of hospital admission. The measure of association was an odds ratio (OR) by univariate and multiple logistic regression. The multiple logistic regression has been carried out to take confounding factors and potential effect modifiers into account. The CVE was computed as CVE = (1 - OR)*100 with 95% confidence interval.

Results

Among 19314 admitted patients, of whom 13216 (68.4%) were cases and 6098 (31.6%) were controls, 1313 (6.8%) died. From total, 5959 (30.8%) patients had received the vaccine in which one, two, and booster doses were 2443 (12.6%), 2796 (14.5٪), and 720 (3.7٪), respectively. The estimated adjusted effectiveness of only one dose, two doses and booter vaccination were 22% (95% CI: 14%-29%), 35% (95% CI: 29%-41%) and 33% (95% CI: 16%-47%), respectively. In addition, the adjusted vaccine effectiveness against severe outcome was 33% (95% CI: 19%- 44%), 34% (95% CI: 20%- 45%) and 20% (95% CI: -29%- 50%) for those who received one, two and booster vaccinations, respectively.

Conclusion

Our study concluded that full vaccination, though less effective compared to similar studies elsewhere, decreased hospital admissions and deaths from COVID-19 in Iran, particularly during the Delta variant period, with an observed decline during the Omicron variant dominance.

Discovery of a Peptoid-Based Nanoparticle Platform for Therapeutic mRNA Delivery via Diverse Library Clustering and Structural Parametrization

Nanoparticle-mediated mRNA delivery has emerged as a promising therapeutic modality, but its growth is still limited by the discovery and optimization of effective and well-tolerated delivery strategies. Lipid nanoparticles containing charged or ionizable lipids are an emerging standard for in vivo mRNA delivery, so creating facile, tunable strategies to synthesize these key lipid-like molecules is essential to advance the field. Here, we generate a library of N-substituted glycine oligomers, peptoids, and undertake a multistage down-selection process to identify lead candidate peptoids as the ionizable component in our Nutshell nanoparticle platform. First, we identify a promising peptoid structural motif by clustering a library of >200 molecules based on predicted physical properties and evaluate members of each cluster for reporter gene expression in vivo. Then, the lead peptoid motif is optimized using design of experiments methodology to explore variations on the charged and lipophilic portions of the peptoid, facilitating the discovery of trends between structural elements and nanoparticle properties. We further demonstrate that peptoid-based Nutshells leads to expression of therapeutically relevant levels of an anti-respiratory syncytial virus antibody in mice with minimal tolerability concerns or induced immune responses compared to benchmark ionizable lipid, DLin-MC3-DMA. Through this work, we present peptoid-based nanoparticles as a tunable delivery platform that can be optimized toward a range of therapeutic programs.

Lipid- and Polymer-Based Nanocarrier Platforms for Cancer Vaccine Delivery

Cancer immunotherapy has gained popularity in recent years in the search for effective treatment modalities for various malignancies, particularly those that are resistant to conventional chemo- and radiation therapy. Cancer vaccines target the cancer-immunity cycle by boosting the patient's own immune system to recognize and kill cancer cells, thus serving as both preventative and curative therapeutic tools. Among the different types of cancer vaccines, those based on nanotechnology have shown great promise in advancing the field of cancer immunotherapy. Lipid-based nanoparticles (NPs) have become the most advanced platforms for cancer vaccine delivery, but polymer-based NPs have also received considerable interest. This Review aims to provide an overview of the nanotechnology-enabled cancer vaccine landscape, focusing on recent advances in lipid- and polymer-based nanovaccines and their hybrid structures and discussing the challenges against the clinical translation of these important nanomedicines.

Safety and Immunogenicity of an mRNA-1273 Booster in Children

BACKGROUND

A 2-dose mRNA-1273 primary series in children aged 6 months-5 years (25-µg) and 6-11 years (50-µg) had an acceptable safety profile and was immunogenic in the phase 2/3 KidCOVE study. We present data from KidCOVE participants who received an mRNA-1273 booster dose.

METHODS

An mRNA-1273 booster dose (10-µg for children aged 6 months-5 years; 25-µg for children aged 6-11 years; age groups based on participant age at enrollment) was administered ≥6 months after primary series completion. The primary safety objective was the safety and reactogenicity of an mRNA-1273 booster dose. The primary immunogenicity objective was to infer efficacy of an mRNA-1273 booster dose by establishing noninferiority of neutralizing antibody (nAb) responses after a booster in children compared with nAb responses observed after the mRNA-1273 primary series in young adults (18-25 years) from the pivotal efficacy study. Data were collected from March 2022 to June 2023.

RESULTS

Overall, 153 (6 months-5 years) and 2519 (6-11 years) participants received an mRNA-1273 booster dose (median age at receipt of booster: 2 and 10 years, respectively). The booster dose safety profile was generally consistent with that of the primary series in children; no new safety concerns were identified. An mRNA-1273 booster dose elicited robust nAb responses against ancestral SARS-CoV-2 among children and met prespecified noninferiority success criteria when compared with responses observed after the primary series in young adults.

CONCLUSIONS

Safety and immunogenicity data support administration of a mRNA-1273 booster dose in children aged 6 months to 11 years.

CLINICAL TRIALS REGISTRATION

NCT04796896.

Peptide-enabled ribonucleoprotein delivery for CRISPR engineering (PERC) in primary human immune cells and hematopoietic stem cells

Peptide-enabled ribonucleoprotein delivery for CRISPR engineering (PERC) is a new approach for ex vivo genome editing of primary human cells. PERC uses a single amphiphilic peptide reagent to mediate intracellular delivery of the same pre-formed CRISPR ribonucleoprotein enzymes that are broadly used in research and therapeutics, resulting in high-efficiency editing of stimulated immune cells and cultured hematopoietic stem and progenitor cells (HSPCs). PERC facilitates nuclease-mediated gene knockout, precise transgene knock-in, and base editing. PERC involves mixing the CRISPR ribonucleoprotein enzyme with peptide and then incubating the formulation with cultured cells. For efficient transgene knock-in, adeno-associated virus (AAV) bearing homology-directed repair template DNA may be included. In contrast to electroporation, PERC is appealing as it requires no dedicated hardware and has less impact on cell phenotype and viability. Due to the gentle nature of PERC, delivery can be performed multiple times without substantial impact to cell health or phenotype. Here we report methods for improved PERC-mediated editing of T cells as well as novel methods for PERC-mediated editing of HSPCs, including knockout and precise knock-in. Editing efficiencies can surpass 90% using either Cas9 or Cas12a in primary T cells or HSPCs. Because PERC calls for only three readily available reagents - protein, RNA, and peptide - and does not require dedicated hardware for any step, PERC demands no special expertise and is exceptionally straightforward to adopt. The inherent compatibility of PERC with established cell engineering pipelines makes this approach appealing for rapid deployment in research and clinical settings.

Evaluation of Clinical Effects of COVID-19 Infection and Vaccines on Myasthenia Gravis

Introduction

In this study, we aimed to investigate the clinical effects of COVID-19 infection and vaccines on Myasthenia gravis (MG) during the pandemic.

Methods

A total of 141 MG patients between April 2020 and December 2021 were retrospectively analyzed. Data including demographic and clinical characteristics of patients, COVID-19 test results, and vaccine types (mRNA-BNT162b2 and/or inactivated-CoronaVac) were recorded. All patients were followed by face-to-face interviews and/or phone calls. Worsening MG symptoms after COVID-19 infection or vaccines were noted.

Results

A total of 60 patients were diagnosed with COVID-19, and reverse transcriptase-polymerase chain reaction test results were COVID-19 positive in 54 (90%) patients. Twenty-eight (46.7%) patients had lung involvement, while 20(33.3%) patients were followed in the ward. Twelve (20%) patients were followed in the intensive care unit, and two of them (3.3%) died. Both deceased patients were unvaccinated. The most common symptoms were fatigue (78.3%), and 13(21.7%) patients were asymptomatic. Of the patients, 96(68%) received at least one dose BNT162b2 or CoronaVac, while 30.4% of the patients received ≥3 doses of vaccines. The local skin irritation and fatigue rate was significantly higher with BNT162b2 vaccine than CoronaVac (p<0.001 and p=0.004, respectively). No serious side effect was observed with either vaccine. Five patients had worsening MG symptoms after vaccination during a six-week follow-up. None of the patients experienced myasthenic crises.

Conclusion

Our study results suggest that COVID-19 infection affects MG similar to the general population and does not lead to worsening MG symptoms. Both mRNA and inactivated vaccines with proven efficacy can be used safely in MG patients.

Effectiveness of the 2023-2024 Formulation of the COVID-19 Messenger RNA Vaccine

BACKGROUND

The purpose of this study was to evaluate whether the 2023-2024 formulation of the coronavirus disease 2019 (COVID-19) messenger RNA vaccine protects against COVID-19.

METHODS

Cleveland Clinic employees when the 2023-2024 formulation of the COVID-19 messenger RNA vaccine became available to employees were included. Cumulative incidence of COVID-19 over the following 17 weeks was examined prospectively. Protection provided by vaccination (analyzed as a time-dependent covariate) was evaluated using Cox proportional hazards regression, with time-dependent coefficients used to separate effects before and after the JN.1 lineage became dominant. The analysis was adjusted for the propensity to get tested, age, sex, pandemic phase when the last prior COVID-19 episode occurred, and the number of prior vaccine doses.

RESULTS

Among 48 210 employees, COVID-19 occurred in 2462 (5.1%) during the 17 weeks of observation. In multivariable analysis, the 2023-2024 formula vaccinated state was associated with a significantly lower risk of COVID-19 before the JN.1 lineage became dominant (hazard ratio = .58; 95% confidence interval [CI] = .49-.68; P < .001), and lower risk but one that did not reach statistical significance after (hazard ratio = .81; 95% CI = .65-1.01; P = .06). Estimated vaccine effectiveness was 42% (95% CI = 32-51) before the JN.1 lineage became dominant, and 19% (95% CI = -1-35) after. Risk of COVID-19 was lower among those previously infected with an XBB or more recent lineage and increased with the number of vaccine doses previously received.

CONCLUSIONS

The 2023-2024 formula COVID-19 vaccine given to working-aged adults afforded modest protection overall against COVID-19 before the JN.1 lineage became dominant, and less protection after.

Unlocking insights: Navigating COVID-19 challenges and Emulating future pandemic Resilience strategies with strengthening natural immunity

The original COVID-19 vaccines, developed against SARS-CoV-2, initially mitigated hospitalizations. Bivalent vaccine boosters were used widely during 2022-23, but the outbreaks persisted. Despite this, hospitalizations, mortality, and outbreaks involving dominant mutants like Alpha and Delta increased during winters when the population's vitamin D levels were at their lowest. Notably, 75 % of human immune cell/system functions, including post-vaccination adaptive immunity, rely on adequate circulatory vitamin D levels. Consequently, hypovitaminosis compromises innate and adaptive immune responses, heightening susceptibility to infections and complications. COVID-19 vaccines primarily target SARS-CoV-2 Spike proteins, thus offering only a limited protection through antibodies. mRNA vaccines, such as those for COVID-19, fail to generate secretory/mucosal immunity-like IgG responses, rendering them ineffective in halting viral spread. Additionally, mutations in the SARS-CoV-2 binding domain reduce immune recognition by vaccine-derived antibodies, leading to immune evasion by mutant viruses like Omicron variants. Meanwhile, the repeated administration of bivalent boosters intended to enhance efficacy resulted in the immunoparesis of recipients. As a result, relying solely on vaccines for outbreak prevention, it became less effective. Dominant variants exhibit increased affinity to angiotensin-converting enzyme receptor-2, enhancing infectivity but reducing virulence. Meanwhile, spike protein-related viral mutations do not impact the potency of widely available, repurposed early therapies, like vitamin D and ivermectin. With the re-emergence of COVID-19 and impending coronaviral pandemics, regulators and health organizations should proactively consider approval and strategic use of cost-effective adjunct therapies mentioned above to counter the loss of vaccine efficacy against emerging variants and novel coronaviruses and eliminate vaccine- and anti-viral agents-related serious adverse effects. Timely implementation of these strategies could reduce morbidity, mortality, and healthcare costs and provide a rational approach to address future epidemics and pandemics. This perspective critically reviews relevant literature, providing insights, justifications, and viewpoints into how the scientific community and health authorities can leverage this knowledge cost-effectively.

Advances in Engineering Circular RNA Vaccines

Engineered circular RNAs (circRNAs) are a class of single-stranded RNAs with head-to-tail covalently linked structures that integrate open reading frames (ORFs) and internal ribosome entry sites (IRESs) with the function of coding and expressing proteins. Compared to mRNA vaccines, circRNA vaccines offer a more improved method that is safe, stable, and simple to manufacture. With the rapid revelation of the biological functions of circRNA and the success of Severe Acute Respiratory Coronavirus Type II (SARS-CoV-2) mRNA vaccines, biopharmaceutical companies and researchers around the globe are attempting to develop more stable circRNA vaccines for illness prevention and treatment. Nevertheless, research on circRNA vaccines is still in its infancy, and more work and assessment are needed for their synthesis, delivery, and use. In this review, based on the current understanding of the molecular biological properties and immunotherapeutic mechanisms of circRNA, we summarize the current preparation methods of circRNA vaccines, including design, synthesis, purification, and identification. We discuss their delivery strategies and summarize the challenges facing the clinical application of circRNAs to provide references for circRNA vaccine-related research.

Exposure proximal immune correlates analysis

Immune response decays over time, and vaccine-induced protection often wanes. Understanding how vaccine efficacy changes over time is critical to guiding the development and application of vaccines in preventing infectious diseases. The objective of this article is to develop statistical methods that assess the effect of decaying immune responses on the risk of disease and on vaccine efficacy, within the context of Cox regression with sparse sampling of immune responses, in a baseline-naive population. We aim to further disentangle the various aspects of the time-varying vaccine effect, whether direct on disease or mediated through immune responses. Based on time-to-event data from a vaccine efficacy trial and sparse sampling of longitudinal immune responses, we propose a weighted estimated induced likelihood approach that models the longitudinal immune response trajectory and the time to event separately. This approach assesses the effects of the decaying immune response, the peak immune response, and/or the waning vaccine effect on the risk of disease. The proposed method is applicable not only to standard randomized trial designs but also to augmented vaccine trial designs that re-vaccinate uninfected placebo recipients at the end of the standard trial period. We conducted simulation studies to evaluate the performance of our method and applied the method to analyze immune correlates from a phase III SARS-CoV-2 vaccine trial.

Enhancing Immune Responses against SARS-CoV-2 Variants in Aged Mice with INDUK: A Chimeric DNA Vaccine Encoding the Spike S1-TM Subunits

Currently available vaccines against COVID-19 showed high efficacy against the original strain of SARS-CoV-2 but progressively lower efficacy against new variants. In response to emerging SARS-CoV-2 strains, we propose chimeric DNA vaccines encoding the spike antigen, including a combination of selected key mutations from different variants of concern. We developed two DNA vaccines, pVAX-S1-TM-D614G and pVAX-S1-TM-INDUK (INDUK), encoding the SARS-CoV-2 S1 spike subunit in fusion with the transmembrane region that allows protein trimerization as predicted by in silico analysis. pVAX-S1-TM-D614G included the dominant D614G substitution, while the chimeric vaccine INDUK contained additional selected mutations from the Delta (E484Q and L452R) and Alpha (N501Y and A570D) variants. Considering that aging is a risk factor for severe disease and that suboptimal vaccine responses were observed in older individuals, the immunogenicity of pVAX-S1-TM-D614G and INDUK was tested in both young and aged C57BL/6 mice. Two vaccine doses were able to trigger significant anti-SARS-CoV-2 antibody production, showing neutralizing activity. ELISA tests confirmed that antibodies induced by pVAX-S1-TM-D614G and INDUK were able to recognize both Wuhan Spike and Delta variant Spike as trimers, while neutralizing antibodies were detected by an ACE2:SARS-CoV-2 Spike S1 inhibitor screening assay, designed to assess the capacity of antibodies to block the interaction between the viral spike S1 protein and the ACE2 receptor. Although antibody titer declined within six months, a third booster dose significantly increased the magnitude of humoral response, even in aged individuals, suggesting that immune recall can improve antibody response durability. The analysis of cellular responses demonstrated that vaccination with INDUK elicited an increase in the percentage of SARS-CoV-2-specific IFN-γ producing T lymphocytes in immunized young mice and TNF-α-producing T lymphocytes in both young and aged mice. These findings not only hold immediate promise for addressing evolving challenges in SARS-CoV-2 vaccination but also open avenues to refine strategies and elevate the effectiveness of next-generation vaccines.

Efficacy of a stable broadly protective subunit vaccine platform against SARS-CoV-2 variants of concern

The emergence and ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted the need for rapid vaccine development platforms that can be updated to counteract emerging variants of currently circulating and future emerging coronaviruses. Here we report the development of a "train model" subunit vaccine platform that contains a SARS-CoV-2 Wuhan S1 protein (the "engine") linked to a series of flexible receptor binding domains (RBDs; the "cars") derived from SARS-CoV-2 variants of concern (VOCs). We demonstrate that these linked subunit vaccines when combined with Sepivac SWE™, a squalene in water emulsion (SWE) adjuvant, are immunogenic in Syrian hamsters and subsequently provide protection from infection with SARS-CoV-2 VOCs Omicron (BA.1), Delta, and Beta. Importantly, the bivalent and trivalent vaccine candidates offered protection against some heterologous SARS-CoV-2 VOCs that were not included in the vaccine design, demonstrating the potential for broad protection against a range of different VOCs. Furthermore, these formulated vaccine candidates were stable at 2-8 °C for up to 13 months post-formulation, highlighting their utility in low-resource settings. Indeed, our vaccine platform will enable the development of safe and broadly protective vaccines against emerging betacoronaviruses that pose a significant health risk for humans and agricultural animals.

Tailoring biomaterials for vaccine delivery

Biomaterials are substances that can be injected, implanted, or applied to the surface of tissues in biomedical applications and have the ability to interact with biological systems to initiate therapeutic responses. Biomaterial-based vaccine delivery systems possess robust packaging capabilities, enabling sustained and localized drug release at the target site. Throughout the vaccine delivery process, they can contribute to protecting, stabilizing, and guiding the immunogen while also serving as adjuvants to enhance vaccine efficacy. In this article, we provide a comprehensive review of the contributions of biomaterials to the advancement of vaccine development. We begin by categorizing biomaterial types and properties, detailing their reprocessing strategies, and exploring several common delivery systems, such as polymeric nanoparticles, lipid nanoparticles, hydrogels, and microneedles. Additionally, we investigated how the physicochemical properties and delivery routes of biomaterials influence immune responses. Notably, we delve into the design considerations of biomaterials as vaccine adjuvants, showcasing their application in vaccine development for cancer, acquired immunodeficiency syndrome, influenza, corona virus disease 2019 (COVID-19), tuberculosis, malaria, and hepatitis B. Throughout this review, we highlight successful instances where biomaterials have enhanced vaccine efficacy and discuss the limitations and future directions of biomaterials in vaccine delivery and immunotherapy. This review aims to offer researchers a comprehensive understanding of the application of biomaterials in vaccine development and stimulate further progress in related fields.