Development of SARS-CoV-2 vaccines: challenges, risks, and the way forward

Gold Nanoparticle Virus-like Particles Presenting SARS-CoV-2 Spike Protein: Synthesis, Biophysical Properties and Immunogenicity in BALB/c Mice

Gold nanoparticles (AuNPs) decorated with antigens have recently emerged as promising tools for vaccine development due to their innate ability to provide stability to antigens and modulate immune responses. In this study, we have engineered deactivated virus-like particles (VLPs) by precisely functionalizing gold cores with coronas comprising the full SARS-CoV-2 spike protein (S). Using BALB/c mice as a model, we investigated the immunogenicity of these S-AuNPs-VLPs. Our results demonstrate that S-AuNPs-VLPs consistently enhanced antigen-specific antibody responses compared to the S protein free in solution. This enhancement included higher binding antibody titers, higher neutralizing capacity of antibodies, and stronger T-cell responses. Compared to the mRNA COVID-19 vaccine, where the S protein is synthesized in situ, S-AuNPs-VLPs induced comparable binding and neutralizing antibody responses, but substantially superior T-cell responses. In conclusion, our study highlights the potential of conjugated AuNPs as an effective antigen-delivery system for protein-based vaccines targeting a broad spectrum of infectious diseases and other emergent viruses.

The Healthcare Study Examines the Humoral Anti-S1 Antibody Response Following mRNA Vaccination, Comparing Individuals with and without Prior SARS-CoV-2 Infection

Vaccines targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been pivotal in curtailing the spread of infection. Health care workers, as frontline responders, were among the first to receive vaccination to mitigate coronavirus disease in 2019 (COVID-19) transmission. This study aimed to assess the humoral response elicited by mRNA vaccines, specifically measuring antibodies against the spike S1 protein, a marker of immune response. A cohort of 649 health care workers received three doses of mRNA vaccine, with antibody levels evaluated before and after each dose within a 2- to 3-week interval. Participants were stratified into groups based on prior exposure to the virus: those without prior contact (440 individuals) and those with a history of infection (209 individuals). Among the latter, cases of SARS-CoV-2 infection ranged from asymptomatic (92 individuals) to mild symptomatic (117 individuals). Participants with a history of infection exhibited elevated levels of IgG antibodies against the S1 protein prior to vaccination. Notably, both immunoglobulin IgA class (IgA) and immunoglobulin IgG class (IgG) antibody responses increased significantly post-vaccination, peaking after the second dose for IgG and after the third dose for IgA. Interestingly, the immune response to the vaccine did not vary significantly based on the symptomatic or asymptomatic nature of prior infection. Furthermore, the study findings indicate that completion of the vaccination regimen led to sustained antibody production lasting between 6 months and 9 months. This study underscores the robust and enduring humoral response elicited by mRNA vaccines, particularly among health care workers, irrespective of prior SARS-CoV-2 exposure.

A Comprehensive Review on Cardiovascular Complications of COVID-19: Unraveling the Link to Bacterial Endocarditis

The global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has ushered in a new era of understanding the multifaceted nature of infectious diseases. Beyond its well-documented respiratory impact, COVID-19 has unveiled intricate interactions with the cardiovascular system, with potential implications that extend to bacterial endocarditis. This review explores the complex interplay between COVID-19 and bacterial endocarditis, elucidating shared risk factors, theoretical mechanisms, and clinical implications. We examine the diverse cardiovascular manifestations of COVID-19, ranging from myocarditis and thromboembolic events to arrhythmias, and delve into the pathogenesis, clinical features, and diagnostic challenges of bacterial endocarditis. By analyzing potential connections, such as viral-induced endothelial disruption and immune modulation, we shed light on the plausible relationship between COVID-19 and bacterial endocarditis. Our synthesis highlights the significance of accurate diagnosis, optimal management, and interdisciplinary collaboration in addressing the challenges posed by these intricate interactions. In addition, we underscore the importance of future research, emphasizing prospective studies on bacterial endocarditis incidence and investigations into the long-term cardiovascular effects of COVID-19. As the boundaries of infectious diseases and cardiovascular complications converge, this review calls for continued research, vigilance, and coordinated efforts to enhance patient care and public health strategies in a rapidly evolving landscape.

Evaluation of the Effect of İnfection and İmmunity on the Tear Film by Scheimpflug-Placido Disc Topography- A Case Control Study

PURPOSE

We aimed to compare the tear film stability of individuals who had recovered from coronavirus disease (COVID-19), that of individuals vaccinated against COVID-19 and that of healthy individuals in a control group.

METHODS

This study included 61 eyes of 61 post-COVID-19 patients, 63 eyes of 63 participants who had received at least two doses of the SARS-CoV-2 mRNA BNT162b2 (Pfizer-BioNTech) vaccine, and 57 eyes of healthy individuals in a control group. We compared the groups' tear film stability.

RESULTS

The mean non-invasive first tear break-up time (NIF-BUT) value was 4.1±2.7 seconds in the post-COVID-19 group, 4.7±2.9 seconds in the vaccinated group, and 5.8±2.8 seconds in the control group. This value was statistically significantly lower in the post-COVID-19 and vaccinated groups than in the control group (p= 0.007). The rate of superotemporal (ST) quadrant breakup, statistically significantly higher in the vaccinated group than in the other two groups (p=0.001). According to a qualitative examination of the results, at least one breakup occurred in 47 (77%) of the post-COVID-19 participants' eyes, 50 (79.4%) of the vaccinated group's eyes, and 33 (57.9%) of the control group's eyes. In terms of this qualitative value, the post-COVID-19 and vaccinated groups had significantly higher breakup rates than the control group (p=0.018).

CONCLUSIONS

Destabilization in the tear film was more common in both the post covid group and the vaccinated group. In addition to individuals who have post-Covid, we think that post-vaccination individuals should be followed closely in terms of ocular surface diseases.

An Effective Platform for SARS-CoV-2 Prevention by Combining Neutralization and RNAi Technology

At present, the coronavirus disease 2019 (COVID-19) pandemic is a global health crisis. Scientists all over the globe are urgently looking forward to an effective solution to prevent the spread of the epidemic and avoid more casualties at an early date. In this study, we establish an effective platform for the prevention of SARS-CoV-2 by combining the neutralization strategy and RNAi technology. To protect normal cells from infection, the customized cells are constructed to stably express viral antigenic receptor ACE2 on the cell membrane. These modified cells are used as bait for inducing the viral entry. The transcription and replication activities of viral genome are intercepted subsequently by the intracellular shRNAs, which are complementary to the viral gene fragments. A pseudotyped virus reconstructed from the HIV lentivirus is utilized as a virus model, by which we validate the feasibility and effectiveness of our strategy in vitro. Our work establishes an initial model and lays the foundation for future prevention and treatment of various RNA viruses.

COVID-19 management landscape: A need for an affordable platform to manufacture safe and efficacious biotherapeutics and prophylactics for the developing countries

To gain world-wide control over COVID-19 pandemic, it is necessary to have affordable and accessible vaccine and monoclonal antibody technologies across the globe. In comparison to the western countries, Asian and African countries have less percentage of vaccination done which warrants urgent attention. Global manufacturer production capacities, dependency on advanced nations for the supply of vaccines or the raw material, national economy, limited research facilities, and logistics could be the factors. This review article elaborates the existing therapeutic and prophylactic strategies available for COVID-19, currently adopted vaccine and monoclonal antibody platforms for SARS-CoV-2 along with the approaches to bridge the gap prevailing in the challenges faced by low- and middle-income countries. We believe adoption of yeast-derived P. pastoris technology can help in developing safe, proven, easy to scale-up, and affordable recombinant vaccine or monoclonal antibodies against SARS-CoV-2. This platform has the advantage of not requiring a dedicated or specialized facility making it an affordable option using existing manufacturing facilities, without significant additional capital investments. Besides, the technology platform of multiantigen vaccine approach and monoclonal antibody cocktail will serve as effective weapons to combat the threat posed by the SARS-CoV-2 variants. Successful development of vaccines and monoclonal antibodies using such a technology will lead to self-sufficiency of these nations in terms of availability of vaccines and monoclonal antibodies.

HPV Vaccination: Polish-Language Facebook Discourse Analysis

Social media platforms are widely used for spreading vaccine-related information. The objectives of this paper are to characterize Polish-language human papillomavirus (HPV) vaccination discourse on Facebook and to trace the possible influence of the COVID-19 pandemic on changes in the HPV vaccination debate. A quantitative and qualitative analysis was carried out based on data collected with a tool for internet monitoring and social media analysis. We found that the discourse about HPV vaccination bearing negative sentiment is centralized. There are leaders whose posts generate the bulk of anti-vaccine traffic and who possess relatively greater capability to influence recipients’ opinions. At the beginning of the COVID-19 pandemic vaccination debate intensified, but there is no unequivocal evidence to suggest that interest in the HPV vaccination topic changed.

Case Report: Probable Myocarditis After Covid-19 mRNA Vaccine in a Patient With Arrhythmogenic Left Ventricular Cardiomyopathy

Arrhythmogenic left ventricular cardiomyopathy (ALVC) is a rare heritable heart-muscle disorder characterized by a progressive loss of left ventricular myocardium and its replacement by fibrofatty tissue. Myocarditis is an inflammatory disease of the heart that may occur secondary to infections, immune system activation or exposure to drugs. Hot phases of ALVC present with chest pain and troponin rise, mimicking acute viral myocarditis and indicate a progression of the disease. Recently, myocarditis has also been described as an infrequent complication of coronavirus disease 2019 (Covid-19) mRNA vaccines. We herein report for the first time a case of probable myocarditis induced by Covid-19 vaccine in a patient with previous medical history of ALVC. We aim to highlight the common characteristics of ALVC and Covid-19 vaccine myocarditis and work through the differential diagnosis of these two entities.

A decoy strategy to activate the immune system

An approach comprising a novel fusion protein and inactivated virus, as a more efficacious vaccine against invading viruses is presented, using SARS-CoV-2 as a most prominent example. The fusion protein consists of the Hepatitis B surface antigen (HBsAg) conjugated to the N-terminal helix (NTH) of Angiotensin-Converting Enzyme 2 (ACE2), which is the receptor for SARS-CoV-2. For vaccination, this fusion protein is to be administered together with the whole killed virus. The NTH would bind to the Receptor Binding Domain (RBD) of the Spike protein of the killed virus. Due to HBsAg acting as a decoy, immune responses would be mounted. Neutralizing antibodies (NAbs) pre-existing in people already vaccinated with the recombinant Hepatitis B vaccine, fresh production of NAbs, and NAbs produced by memory B cells would bind to the HBsAg. This would lead to "presentation" of the killed virus to elements of the immune system at close range. Also, there would be enhanced opsonization and effective antigen presentation. This two-component vaccine could be a platform strategy, wherein HBsAg could be linked to the part of the cellular receptor that any new intractable virus binds to, and is administered together with whole inactivated virus. Now, the same fusion protein, administered by itself to persons with infection, would have therapeutic action, yet by harnessing elements of the immune system. NAbs would bind to the fusion protein as above, the NTH of which would bind to the RBDs of the infecting virus, which, in effect would be neutralized.

Detection of IFNγ-Secreting CD4+ and CD8+ Memory T Cells in COVID-19 Convalescents after Stimulation of Peripheral Blood Mononuclear Cells with Live SARS-CoV-2

Background: New coronavirus SARS-CoV-2, a causative agent of the COVID-19 pandemic, has been circulating among humans since November 2019. Multiple studies have assessed the qualitative and quantitative characteristics of virus-specific immunity in COVID-19 convalescents, however, some aspects of the development of memory T-cell responses after natural SARS-CoV-2 infection remain uncovered. Methods: In most of published studies T-cell immunity to the new coronavirus is assessed using peptides corresponding to SARS-CoV-1 or SARS-CoV-2 T-cell epitopes, or with peptide pools covering various parts of the viral proteins. Here, we determined the level of CD4⁺ and CD8⁺ memory T-cell responses in COVID-19 convalescents by stimulating PBMCs collected 1 to 6 months after recovery with sucrose gradient-purified live SARS-CoV-2. IFNγ production by the central and effector memory helper and cytotoxic T cells was assessed by intracellular cytokine staining assay and flow cytometry. Results: Stimulation of PBMCs with live SARS-CoV-2 revealed IFNγ-producing T-helper effector memory cells with CD4⁺CD45RA⁻CCR7⁻ phenotype, which persisted in circulation for up to 6 month after COVID-19. In contrast, SARS-CoV-2-specific IFNγ-secreting cytotoxic effector memory T cells were found at significant levels only shortly after the disease, but rapidly decreased over time. Conclusion: The stimulation of immune cells with live SARS-CoV-2 revealed a rapid decline in the pool of effector memory CD8⁺, but not CD4⁺, T cells after recovery from COVID-19. These data provide additional information on the development and persistence of cellular immune responses after natural infection, and can inform further development of T cell-based SARS-CoV-2 vaccines.

Preliminary evidence on the safety profile of BNT162b2 (Comirnaty): new insights from data analysis in EudraVigilance and adverse reaction reports from an Italian health facility

The first vaccine against SARS-CoV-2 made available in Italy has been BNT162b2, the two-dose mRNA-based vaccine developed by Pfizer-BioNTech. The ASST Fatebenefratelli-Sacco hospital is located in one of the areas most affected by the pandemic, and to date over 2000 healthcare professionals have been injected with both vaccine doses. We have collected all spontaneous safety reports in which BNT162b2 was designated as the possible cause. We also have carried out a descriptive analysis of reports submitted in EudraVigilance in the same time-frame and compared our findings with those observed in clinical trials. We have identified several new and unexpected adverse reactions that will be helpful for reviewing the safety profile defined in the Summary of Product Characteristics for this vaccine.

Perspective on therapeutic and diagnostic potential of camel nanobodies for coronavirus disease-19 (COVID-19)

In this paper, we focus on the camelid nanobodies as a revolutionary therapy that can guide efforts to discover new drugs for Coronavirus disease (COVID-19). The small size property makes nanobodies capable of penetrating efficiently into tissues and recognizing cryptic antigens. Strong antigen affinity and stability in the gastrointestinal tract allow them to be used via oral administration. In fact, the use of nanobodies as inhalant can be directly delivered to the target organ, conferring high pulmonary drug concentrations and low systemic drug concentrations and minimal systemic side effects. For that, nanobodies are referred as a class of next-generation antibodies. Nanobodies permit the construction of multivalent formats that may achieve ultra-high neutralization potency and then may prevent mutational escape and can neutralize a wide range of SARS-CoV-2 variants. Due to their distinctive characteristics, nanobodies can be of great use in the development of promising treatment or preventive strategies against SARS-CoV-2 infection. In this review, the state-of-the-art of camel nanobodies design strategies against the virus including SARS-CoV-2 are critically summarized. The application of general nanotechnology was also discussed to mitigate and control emerging SARS-CoV-2 infection.

Newcastle Disease Virus-Like Particles Displaying Prefusion-Stabilized SARS-CoV-2 Spikes Elicit Potent Neutralizing Responses

The COVID-19 pandemic highlights an urgent need for vaccines that confer protection from SARS-CoV-2 infection. One approach to an effective COVID-19 vaccine may be through the display of SARS-CoV-2 spikes on the surface of virus-like particles, in a manner structurally mimicking spikes on a native virus. Here we report the development of Newcastle disease virus-like particles (NDVLPs) displaying the prefusion-stabilized SARS-CoV-2 spike ectodomain (S2P). Immunoassays with SARS-CoV-2-neutralizing antibodies revealed the antigenicity of S2P-NDVLP to be generally similar to that of soluble S2P, and negative-stain electron microscopy showed S2P on the NDVLP surface to be displayed with a morphology corresponding to its prefusion conformation. Mice immunized with S2P-NDVLP showed substantial neutralization titers (geometric mean ID50 = 386) two weeks after prime immunization, significantly higher than those elicited by a molar equivalent amount of soluble S2P (geometric mean ID50 = 17). Neutralizing titers at Week 5, two weeks after a boost immunization with S2P-NDVLP doses ranging from 2.0 to 250 μg, extended from 2125 to 4552, and these generally showed a higher ratio of neutralization versus ELISA than observed with soluble S2P. Overall, S2P-NDVLP appears to be a promising COVID-19 vaccine candidate capable of eliciting substantial neutralizing activity.