Vector-based Vaccines Research Articles

Preclinical Evaluation of TB/FLU-04L-An Intranasal Influenza Vector-Based Boost Vaccine against Tuberculosis.

Tuberculosis is a major global threat to human health. Since the widely used BCG vaccine is poorly effective in adults, there is a demand for the development of a new type of boost tuberculosis vaccine. We designed a novel intranasal tuberculosis vaccine candidate, TB/FLU-04L, which is based on an attenuated influenza A virus vector encoding two mycobacterium antigens, Ag85A and ESAT-6. As tuberculosis is an airborne disease, the ability to induce mucosal immunity is one of the potential advantages of influenza vectors. Sequences of ESAT-6 and Ag85A antigens were inserted into the NS1 open reading frame of the influenza A virus to replace the deleted carboxyl part of the NS1 protein. The vector expressing chimeric NS1 protein appeared to be genetically stable and replication-deficient in mice and non-human primates. Intranasal immunization of C57BL/6 mice or cynomolgus macaques with the TB/FLU-04L vaccine candidate induced Mtb-specific Th1 immune response. Single TB/FLU-04L immunization in mice showed commensurate levels of protection in comparison to BCG and significantly increased the protective effect of BCG when applied in a "prime-boost" scheme. Our findings show that intranasal immunization with the TB/FLU-04L vaccine, which carries two mycobacterium antigens, is safe, and induces a protective immune response against virulent M. tuberculosis.

The Potential of Alternative Therapies and Vaccine Candidates against Helicobacter pylori.

Alternative therapies and vaccination are essential to combat the emergence of multidrug-resistant Helicobacter pylori and to prevent the development of gastroduodenal diseases. This review aimed to systematically review recent studies on alternative therapies, i.e., probiotics, nanoparticles, and natural products from plants, as well as recent progress in H. pylori vaccines at the preclinical stage. Articles published from January 2018 to August 2022 were systematically searched using PubMed, Scopus, Web of Science, and Medline. After the screening process, 45 articles were eligible for inclusion in this review. Probiotics (n = 9 studies) and natural products from plants (n = 28 studies) were observed to inhibit the growth of H. pylori, improve immune response, reduce inflammation, and reduce the pathogenic effects of H. pylori virulence factors. Natural products from plants also showed anti-biofilm activity against H. pylori. However, clinical trials of natural products from plants and probiotics are still lacking. A paucity of data assessing the nanoparticle activity of N-acylhomoserine lactonase-stabilized silver against H. pylori was observed. Nonetheless, one nanoparticle study showed anti-biofilm activity against H. pylori. Promising results of H. pylori vaccine candidates (n = 7) were observed at preclinical stage, including elicitation of a humoral and mucosal immune response. Furthermore, the application of new vaccine technology including multi-epitope and vector-based vaccines using bacteria was investigated at the preclinical stage. Taken together, probiotics, natural products from plants, and nanoparticles exhibited antibacterial activity against H. pylori. New vaccine technology shows promising results against H. pylori.

Dermatological Complications of COVID 19 Vaccines: An Updated Review

Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the 2019 coronavirus disease (COVID-19) pandemic, have been rapidly developed and authorized. However, recent studies showed that COVID-19 vaccination is associated with a wide range of dermatological reactions. The most prevalent adverse dermatological reaction observed in observational studies was a delayed large local reaction (DLRs), which is characterized by the appearance of an erythematous and edematous patch at the injection site four days or more after vaccination. Most of these reactions are common in females and resolve spontaneously within a few days to a weak. The second dose of the vaccine was associated with a higher incidence of cutaneous reactions compared to the first dose but milder in intensity. It seems that the Moderna vaccine is associated with a higher incidence of these adverse events compared to the Pfizer vaccine. Furthermore, mRNA vaccines had a higher incidence than vector-based and inactivated vaccines. There is a lack of evidence regarding the side events of the Johnson & Janssen vaccine. Further long-term, multicenter studies are required to compare these vaccines and highlight the best practice in managing these reactions.

A Perspective on Current Flavivirus Vaccine Development: A Brief Review.

The flavivirus genus contains several clinically important pathogens that account for tremendous global suffering. Primarily transmitted by mosquitos or ticks, these viruses can cause severe and potentially fatal diseases ranging from hemorrhagic fevers to encephalitis. The extensive global burden is predominantly caused by six flaviviruses: dengue, Zika, West Nile, yellow fever, Japanese encephalitis and tick-borne encephalitis. Several vaccines have been developed, and many more are currently being tested in clinical trials. However, flavivirus vaccine development is still confronted with many shortcomings and challenges. With the use of the existing literature, we have studied these hurdles as well as the signs of progress made in flavivirus vaccinology in the context of future development strategies. Moreover, all current licensed and phase-trial flavivirus vaccines have been gathered and discussed based on their vaccine type. Furthermore, potentially relevant vaccine types without any candidates in clinical testing are explored in this review as well. Over the past decades, several modern vaccine types have expanded the field of vaccinology, potentially providing alternative solutions for flavivirus vaccines. These vaccine types offer different development strategies as opposed to traditional vaccines. The included vaccine types were live-attenuated, inactivated, subunit, VLPs, viral vector-based, epitope-based, DNA and mRNA vaccines. Each vaccine type offers different advantages, some more suitable for flaviviruses than others. Additional studies are needed to overcome the barriers currently faced by flavivirus vaccine development, but many potential solutions are currently being explored.

An Overview of Adenovirus Vector-based Vaccines against SARS-CoV-2

Adenovirus vectors have been employed to develop a vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for curtailing the Covid-19 pandemic spreading. Many different viral vectors have been mainly targeting the SARS-CoV-2 spike (S) protein as an antigen. Spike (S) protein is comprised of S1 and S2 subunits, in which the receptor-binding domain (RBD) of S1 is responsible for recognizing and engaging with its host cellular receptor protein angiotensin-converting enzyme 2 (ACE2), S2 accounts for membrane fusion of virus and host cell. Chimpanzee adenovirus was also used as a vector vaccine for SARS-CoV-2 (ChAdSARS-CoV-2-S) by intramuscular injection, and intranasal administration has been tested. Adenovirus vector-based vaccines are the most advanced, with several vaccines receiving Emergency Use Authorization (EUA). It was shown that rhesus macaques were protected from SARS-CoV-2 challenge after a month of being vaccinated with ChAd-SARS-CoV-2-S. A single intranasal or two intramuscular ChAd-SARSCoV-2-S vaccines could induce humoral antibodies and T cell responses to protect the upper and lower respiratory tract against SARS-CoV-2. As the effectiveness was demonstrated in non-human primates, ChAd-SARS-CoV-2-Sa potential option for preventing SARS-CoV-2 infection in humans. However, detecting novel more transmissible and pathogenic SARS-CoV-2 variants added concerns about the vaccine efficacy and needs monitoring. Moreover, the cause of recently documented rare cases of vaccine indicated immune thrombotic thrombocytopenia. This review article provided details for the adenovirus vector vaccine for SARS-CoV-2 in humans and tried to provide solutions to the adenovirus vector hemagglutinin issue.

Arenaviruses: Old viruses present new solutions for cancer therapy.

Viral-based cancer therapies have tremendous potential, especially in the context of treating poorly infiltrated cold tumors. However, in tumors with intact anti-viral interferon (IFN) pathways, while some oncolytic viruses induce strong innate and adaptive immune responses, they are neutralized before exerting their therapeutic effect. Arenaviruses, particularly the lymphocytic choriomeningitis virus (LCMV) is a noncytopathic virus with preferential cancer tropism and evolutionary mechanisms to escape the immune system for longer and to block early clearance. These escape mechanisms include inhibition of the MAVS dependent IFN pathway and spike protein antigen masking. Regarding its potential for cancer treatment, LCMV is therefore able to elicit long-term responses within the tumor microenvironment (TME), boost anti-tumor immune responses and polarize poorly infiltrating tumors towards a hot phenotype. Other arenaviruses including the attenuated Junin virus vaccine also have anti-tumor effects. Furthermore, the LCMV and Pichinde arenaviruses are currently being used to create vector-based vaccines with attenuated but replicating virus. This review focuses on highlighting the potential of arenaviruses as anti-cancer therapies. This includes providing a molecular understanding of its tropism as well as highlighting past and present preclinical and clinical applications of noncytophatic arenavirus therapies and their potential in bridging the gap in the treatment of cancers weakly responsive or unresponsive to oncolytic viruses. In summary, arenaviruses represent promising new therapies to broaden the arsenal of anti-tumor therapies for generating an immunogenic tumor microenvironment.

Author response to: Letter to Editor in Response to Assessment of early and post COVID-19 vaccination antibody response in healthcare workers: a multicentre cross-sectional study on inactivated, mRNA and vector-based vaccines.

Author response to: Letter to Editor in Response to Assessment of early and post COVID-19 vaccination antibody response in healthcare workers: a multicentre cross-sectional study on inactivated, mRNA and vector-based vaccines.

Biomarkers and Immunotherapy for Colorectal Cancer

Colorectal cancer (CRC) is the second major cause of mortality from cancer globally. Most CRCs are sporadic and may be classified into three main genetic pathways: the chromosomal instability (CIN) pathway, the microsatellite instability (MSI) pathway and the CpG island methylator phenotype (CIMP) pathway, which are associated with genetic mutations or epigenetic alterations and have the possibility to intersect, thus making the treatment of CRC challenging. Immunotherapy has offered some promising insights by inducing antitumor immune responses, but its effectiveness is restricted to certain groups of CRC patients with specific characteristics. Several biomarkers have demonstrated their potentials to predict the outcomes of immunotherapy in individual patients. Some of them include the extent of tumor mutations (MMR/MSI, POLE/POLD1, KRAS), PDL-1 expression, pre-existing immunity and gut microbial compositions. Immune checkpoint inhibitors (ICIs-)-based immunotherapy is considered to be the relatively traditional immunotherapeutic strategy in the treatment of CRC. However, it mainly targets CRCs with defective mismatch repair (dMMR) mechanisms. The more recently developed immunotherapies include cancer vaccines (molecular-based, cell-based and vector-based vaccines) and adoptive cell therapy (ACT), which have the potential to further enhance the stimulation of antitumor immune responses. This review summarizes the predictive biomarkers that have the potential application in CRC treatment, and discusses the immunotherapeutic strategies targeting CRCs that have been developed or are currently under investigation.

Capsid-modified adeno-associated virus vectors as novel vaccine platform for cancer immunotherapy

Immunotherapy has significantly improved treatment outcomes in various cancer entities. To enhance immunogenicity and efficacy, and to further broaden its applicability, co-administration of anti-tumor vaccines is considered as a promising strategy. Here, we introduce adeno-associated virus (AAV) vectors, widely used for invivo gene therapy, as a potent cancer vaccine platform. Our AAV vector-based vaccine combines antigen display on the capsid surface with a vector-mediated antigen overexpression targeting different components of the immune system in a unique chronological order by a single intramuscular application. Thereby, both profound and long-lasting antigen-specific T and B cell immune responses were induced. Moreover, mice receiving the vaccine were protected against tumor growth, demonstrating its efficacy in two tumor models, including the low immunogenic and aggressive B16/F10-Ova melanoma model. Remarkably, this approach was even effective in conditions of a late tumor challenge, i.e., 80days post-vaccination, between 88% (B16/F10-Ova melanoma) and 100% (EG7 thymoma) of mice remained tumor free. Thus, decorating AAV vector particles with antigens by capsid engineering represents a potent vaccine concept for applications in cancer immunotherapy. Its modular and versatile "plug-and-play" framework enables the use of tumor antigens of choice and the easy implementation of additional modifications to enhance immunogenicity further.

Effect of COVID-19 vaccine on blood glucose metrics in Arabic people with type 1 diabetes.

People with diabetes are at a higher risk for coronavirus disease-19 (COVID-19) and hence are prioritized for vaccination. The aim of the current study was to investigate the effects of COVID-19 vaccination on blood glucose control in Arabic people with type 1 diabetes (T1D). Secondary aim was to compare the responses between the two vaccines approved for use in Kuwait. This retrospective study compared ambulatory glucose metrics, using a continuous glucose monitoring device, measured for 14 days before, and 7 days and 14 days after, the first and second dose of the COVID-19 vaccine in Arabic people with Type 1 diabetes (T1D). We also explored possible links with vaccine type and other clinical characteristics. Glucose metrics calculated were time in range (TIR, 3.9-10 mmol/L), time above range (TAR, 10.1- 13.9 mmol/L or >13.9 mmol/L), time below range (TBR, 3- 3.9 mmol/L or <3 mmol/L) and glucose variability (CV). We enrolled 223 participants in the study. Over the 7 days period after the first vaccination dose there was a decrease in TIR (mean difference (SD) -1.9% ± 14.8%; p = 0.05) and increase in TAR >10 mmol/L (2.2% ± 15.9%; p = 0.04), with no effects on TBR. These effects were not seen after the second dose or 14 days after either dose. There was a decrease in CV over the 7 days period after the first (-1.2% ± 7.4%; p = 0.02) and second vaccine doses (-1.1% ± 6.9%; p = 0.03), with no effects noted 14 days after either dose. In subgroup analysis similar effects on TIR and TAR were also seen in those who had received the viral vector-based vaccine, but not the mRNA-based vaccine, although the decrease in CV was seen in those who had received the mRNA based vaccine but not the viral vector-based vaccine. We found a temporary impairment in glucose control in the first 7 days, particularly among individuals receiving viral vector vaccines. The group receiving mRNA vaccine was likely to experience an increase in glucose levels above the target range. However, the temporary change in metrics appears to return to pre-vaccination levels after one-week post-vaccination. The effects on glycemic parameters were more neutral after the second dose.

Heterologous Vector—mRNA Based SARS-CoV-2 Vaccination Strategy Appears Superior to a Homologous Vector—Based Vaccination Scheme in German Healthcare Workers Regarding Humoral SARS-CoV-2 Response Indicating a High Boosting Effect by mRNA Vaccines

Longitudinal humoral SARS-CoV-2 (severe acute respiratory syndrome coronavirus type 2) immunity for up to 15 months due to vaccination, the efficacy of vaccination strategies (homologous, vector-vector versus heterologous, vector-mRNA), the influence of vaccination side effects, and the infection rate in German healthcare workers need to be investigated. In this study, 103 individuals vaccinated against SARS-CoV-2 were enrolled to examine their anti-SARS-CoV-2 anti-N- and anti-RBD/S1-Ig levels. A total of 415 blood samples in lithium heparin tubes were prospectively obtained, and a structured survey regarding medical history, type of vaccine, and vaccination reactions was conducted. All participants demonstrated a humoral immune response, among whom no values decreased below the positivity cutoff. Five to six months after the third vaccination, three participants showed anti-RBD/S1 antibodies of less than 1000 U/mL. We observed higher levels for heterologous mRNA-/vector-based combinations compared to pure vector-based vaccination after the second vaccination, which is harmonized after a third vaccination with the mRNA-vaccine only in both cohorts. The incidence of vaccine breakthrough in a highly exposed cohort was 60.3%. Sustained long-term humoral immunity was observed, indicating the superiority of a heterologous mRNA-/vector-based combination compared to pure vector-based vaccination. There was longevity of anti-RBD/S1 antibodies of at least 4 and up to 7 months without external stimulus. Regarding vaccination reactogenity, the occurrence of local symptoms as pain at the injection site was increased after the first mRNA application compared to the vector-vector cohort with a general decrease in adverse events at later vaccination time points. Overall, a correlation between the humoral vaccination response and vaccination side effects was not observed. Despite the high prevalence of vaccine breakthroughs, these only occurred in the later course of the study when more infectious variants, which are, however, associated with milder courses, were present. These results provide insights into vaccine-related serologic responses, and the study should be expanded using additional vaccine doses and novel variants in the future.

Response to HIV-1 gp160-carrying recombinant virus HSV-1 and HIV-1 VLP combined vaccine in BALB/c mice.

Human immunodeficiency virus (HIV) induced AIDS causes a large number of infections and deaths worldwide every year, still no vaccines are available to prevent infection. Recombinant herpes simplex virus type 1 (HSV-1) vector-based vaccines coding the target proteins of other pathogens have been widely used for disease control. Here, a recombinant virus with HIV-1 gp160 gene integration into the internal reverse (IR) region-deleted HSV-1 vector (HSV-BAC), was obtained by bacterial artificial chromosome (BAC) technology, and its immunogenicity investigated in BALB/c mice. The result showed similar replication ability of the HSV-BAC-based recombinant virus and wild type. Furthermore, humoral and cellular immune response showed superiority of intraperitoneal (IP) administration, compared to intranasally (IN), subcutaneous (SC) and intramuscularly (IM), that evidenced by production of significant antibody and T cell responses. More importantly, in a prime-boost combination study murine model, the recombinant viruses prime followed by HIV-1 VLP boost induced stronger and broader immune responses than single virus or protein vaccination in a similar vaccination regimen. Antibody production was sufficient with huge potential for viral clearance, along with efficient T-cell activation, which were evaluated by the enzyme-linked immunosorbent assay (ELISA) and flow cytometry (FC). Overall, these findings expose the value of combining different vaccine vectors and modalities to improve immunogenicity and breadth against different HIV-1 antigens.

Heterologous prime-boost immunisation with mRNA- and AdC68-based 2019-nCoV variant vaccines induces broad-spectrum immune responses in mice.

The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or 2019-nCoV) variants has been associated with the transmission and pathogenicity of COVID-19. Therefore, exploring the optimal immunisation strategy to improve the broad-spectrum cross-protection ability of COVID-19 vaccines is of great significance. Herein, we assessed different heterologous prime-boost strategies with chimpanzee adenovirus vector-based COVID-19 vaccines plus Wuhan-Hu-1 (WH-1) strain (AdW) and Beta variant (AdB) and mRNA-based COVID-19 vaccines plus WH-1 strain (ARW) and Omicron (B.1.1.529) variant (ARO) in 6-week-old female BALB/c mice. AdW and AdB were administered intramuscularly or intranasally, while ARW and ARO were administered intramuscularly. Intranasal or intramuscular vaccination with AdB followed by ARO booster exhibited the highest levels of cross-reactive IgG, pseudovirus-neutralising antibody (PNAb) responses, and angiotensin-converting enzyme-2 (ACE2)-binding inhibition rates against different 2019-nCoV variants among all vaccination groups. Moreover, intranasal AdB vaccination followed by ARO induced higher levels of IgA and neutralising antibody responses against live 2019-nCoV than intramuscular AdB vaccination followed by ARO. A single dose of AdB administered intranasally or intramuscularly induced broader cross-NAb responses than AdW. Th1-biased cellular immune response was induced in all vaccination groups. Intramuscular vaccination-only groups exhibited higher levels of Th1 cytokines than intranasal vaccination-only and intranasal vaccination-containing groups. However, no obvious differences were found in the levels of Th2 cytokines between the control and all vaccination groups. Our findings provide a basis for exploring vaccination strategies against different 2019-nCoV variants to achieve high broad-spectrum immune efficacy.

Real-world data on the incidence and risk of Guillain–Barré syndrome following SARS-CoV-2 vaccination: a prospective surveillance study

Increasing evidence suggests an association between SARS-CoV-2 vaccines and Guillain–Barré syndrome (GBS). Nevertheless, little is understood about the contributing risk factors and clinical characteristics of GBS post SARS-CoV-2 vaccination. In this prospective surveillance study of 38,828,691 SARS-CoV-2 vaccine doses administered from February 2021 to March 2022 in the Gyeonggi Province, South Korea, 55 cases of GBS were reported post vaccination. We estimated the incidence rate of GBS per million doses and the incidence rate ratio for the vaccine dose, mechanism, age, and sex. Additionally, we compared the clinical characteristics of GBS following mRNA-based and viral vector-based vaccinations. The overall incidence of GBS following SARS-CoV-2 vaccination was 1.42 per million doses. Viral vector-based vaccines were associated with a higher risk of GBS. Men were more likely to develop GBS than women. The third dose of vaccine was associated with a lower risk of developing GBS. Classic sensorimotor and pure motor subtypes were the predominant clinical subtypes, and demyelinating type was the predominant electrodiagnostic subtype. The initial dose of viral-vector based vaccine and later doses of mRNA-based vaccine were associated with GBS, respectively. GBS following SARS-CoV-2 vaccination may not be clinically distinct. However, physicians should pay close attention to the classic presentation of GBS in men receiving an initial dose of viral vector-based SARS-CoV-2 vaccines.

Susac syndrome following COVID-19 vaccination: a case-based review.

COVID-19 vaccine circulation approval was a turning point for the coronavirus pandemic. The current approved COVID-19 vaccines, including messenger ribonucleic acid (mRNA)-based and adenovirus vector-based vaccines, were shown to significantly reduce the disease mortality and severity, and its adverse reactions are mainly mild ones. However, few cases of autoimmune conditions, both flare-ups and new-onset, were described in association with these vaccines. Susac vasculitis (SaS) is a rare autoimmune disease characterized by the clinical triad of encephalopathy, visual disturbances, and sensorineural hearing loss. Its pathogenesis is still not fully understood but is believed to be related to autoimmune processes, including autoantibodies to anti-endothelial cells and cellular immune processes that lead to microvascular damage and, consequently, micro-occlusions of the cerebral, inner ear, and retinal vessels. It has been previously described following vaccination and, most recently, few cases following coronavirus vaccines. We here describe a case of a previously healthy 49-year-old man diagnosed with SaS 5 days following the first dose of the BNT162b2 COVID-19 vaccine.

Lentiviral Vectors as a Vaccine Platform against Infectious Diseases

Lentiviral vectors are among the most effective viral vectors for vaccination. In clear contrast to the reference adenoviral vectors, lentiviral vectors have a high potential for transducing dendritic cells in vivo. Within these cells, which are the most efficient at activating naive T cells, lentiviral vectors induce endogenous expression of transgenic antigens that directly access antigen presentation pathways without the need for external antigen capture or cross-presentation. Lentiviral vectors induce strong, robust, and long-lasting humoral, CD8+ T-cell immunity and effective protection against several infectious diseases. There is no pre-existing immunity to lentiviral vectors in the human population and the very low pro-inflammatory properties of these vectors pave the way for their use in mucosal vaccination. In this review, we have mainly summarized the immunological aspects of lentiviral vectors, their recent optimization to induce CD4+ T cells, and our recent data on lentiviral vector-based vaccination in preclinical models, including prophylaxis against flaviviruses, SARS-CoV-2, and Mycobacterium tuberculosis.

Emerging and re-emerging viral diseases, predisposing risk factors, and implications of international travel: a call for action for increasing vigilance and imposing restrictions under the current threats of recently emerging multiple Omicron subvariants.

Emerging and re-emerging viral diseases, predisposing risk factors, and implications of international travel: a call for action for increasing vigilance and imposing restrictions under the current threats of recently emerging multiple Omicron subvariants.

Coronavirus disease 2019 vaccines: challenges of using global mass vaccination to achieve herd immunity.

Coronavirus disease 2019 vaccines: challenges of using global mass vaccination to achieve herd immunity.

Myopericarditis Associated with the Novavax COVID-19 Vaccine (NVX-CoV2373): A Retrospective Analysis of Individual Case Safety Reports from VigiBase.

Myocarditis and pericarditis have been associated most notably with mRNA vaccines, but the association with a recently authorized adjuvated vaccine (NVX-CoV2373) is controversial. The aim was to analyze the cases of myocarditis and pericarditis in association with NVX-CoV2373 reported to the World Health Organization (WHO) global database of individual case safety reports (ICSRs) for drug monitoring (VigiBase), applying disproportionality analyses. The main characteristics of the ICSRs reporting myopericarditis with NVX-CoV2373 have been summarized. Reporting odds ratios (RORs) as a measure of disproportionality for reported myopericarditis (November 1967-August 2022) have been calculated for NVX-CoV2373; mRNA and adenoviral vector-based vaccines were also included as a reference. In total, 61 ICSRs included NVX-CoV2373. Most of the reports originated in Australia (50; 82.0%); 24 (39.3%) were considered serious. None of them were fatal. The median age of individuals was 35.5 years old, and most were males (38; 62.3%). Chest pain was the most common co-reported event 43 (70.5%). The median induction period was 3 days after immunization. Increased disproportionality for myopericarditis was found for NVX-CoV2373 (ROR 14.47, 95% confidence interval [CI] 11.22-18.67) and mRNA vaccines: BNT162b2 (ROR 17.15, 95% CI 16.88-17.42) and mRNA-1273 (ROR 6.92, 95% CI 6.77-7.08). Higher values were found in males. The adenoviral vector-based vaccine Ad26.COV2.S showed slightly increased disproportionality (ROR 1.83, 95% CI 1.70-1.98), whereas no increased disproportionality was found for ChAdOx1. NVX-CoV2373 vaccine showed a similar increased disproportionality as mRNA vaccines. More evidence from controlled studies is necessary; however, a precautionary approach is warranted. Healthcare professionals should be aware of the potential occurrence of myopericarditis with this new vaccine.

Adenoviral Vector-Based Vaccine Platform for COVID-19: Current Status.

The coronavirus disease (COVID-19) breakout had an unimaginable worldwide effect in the 21st century, claiming millions of lives and putting a huge burden on the global economy. The potential developments in vaccine technologies following the determination of the genetic sequence of SARS-CoV-2 and the increasing global efforts to bring potential vaccines and therapeutics into the market for emergency use have provided a small bright spot to this tragic event. Several intriguing vaccine candidates have been developed using recombinant technology, genetic engineering, and other vaccine development technologies. In the last decade, a vast amount of the vaccine development process has diversified towards the usage of viral vector-based vaccines. The immune response elicited by such vaccines is comparatively higher than other approved vaccine candidates that require a booster dose to provide sufficient immune protection. The non-replicating adenoviral vectors are promising vaccine carriers for infectious diseases due to better yield, cGMP-friendly manufacturing processes, safety, better efficacy, manageable shipping, and storage procedures. As of April 2022, the WHO has approved a total of 10 vaccines around the world for COVID-19 (33 vaccines approved by at least one country), among which three candidates are adenoviral vector-based vaccines. This review sheds light on the developmental summary of all the adenoviral vector-based vaccines that are under emergency use authorization (EUA) or in the different stages of development for COVID-19 management.