Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Immune response of COVID-19 vaccines in solid cancer patients: A meta-analysis

Solid cancer patients, compared to their healthy counterparts, are at a greater risk of contracting and suffering from severe complications and poorer prognosis after COVID-19 infections. They also have different immune responses after doses of COVID-19 vaccination, but limited evidence is available to reveal the effectiveness and help to guide immunization programs for this subpopulation; MEDLINE, Embase, Web of Science, Cochrane Library databases, and clinicaltrials.gov were used to search literature. The pooled seroconversion rate was calculated using a random-effects model and reported with a 95% confidence interval (CI); The review includes 66 studies containing serological responses after COVID-19 vaccination in 13,050 solid cancer patients and 8550 healthy controls. The pooled seropositive rates after the first dose in patients with solid cancer and healthy controls are 55.2% (95% CI 45.9%-64.5% N = 18) and 90.2% (95% CI 80.9%-96.6% N = 13), respectively. The seropositive rates after the second dose in patients with solid cancer and healthy controls are 87.6% (95% CI 84.1%-90.7% N = 50) and 98.9% (95% CI 97.6%-99.7% N = 35), respectively. The seropositive rates after the third dose in patients with solid cancer and healthy controls are 91.4% (95% CI 85.4%-95.9% N = 21) and 99.8% (95% CI 98.1%-100.0% N = 4), respectively. Subgroup analysis finds that study sample size, timing of antibody testing, and vaccine type have influence on the results; Seroconversion rates after COVID-19 vaccination are significantly lower in patients with solid malignancies, especially after the first dose, then shrinking gradually after the following two vaccinations, indicating that subsequent doses or a booster dose should be considered for the effectiveness of this subpopulation.

Immunogenicity of COVID-19 vaccines in patients with cirrhosis: A meta-analysis

The immunogenicity of COVID-19 vaccines in patients with liver cirrhosis remains largely unknown. The purpose of this meta-analysis was to investigate the immunogenicity of COVID-19 vaccines in patients with cirrhosis and compare the humoral and cellular immune responses following complete COVID-19 vaccination between cirrhosis patients and healthy controls. A systematic literature search was conducted in PubMed, EMBASE, and Web of Science from 1 January 2020 to 22 August 2023. Sixteen studies with 2127 cirrhosis patients were included. The pooled seroconversion rate in patients with cirrhosis following complete COVID-19 vaccination was 92.4% (95% CI, 86.2%-96%, I2 = 90%) with significant between-study heterogeneity. Moreover, COVID-19 vaccination elicited a higher humoral immune response in patients of compensated cirrhosis as compared with decompensated cirrhosis (RR = 1.069, 95% CI, 1.011-1.131, I2 = 17%, p = .019). Additionally, 10 studies were included for comparison analysis of seroconversion rate between cirrhosis patients and healthy controls. The results showed that the seroconversion rate in patients with cirrhosis was slightly lower compared with healthy controls (RR = 0.972, 95% CI, 0.955-0.989, I2 = 66%, p = .001). Meanwhile, the pooled RR of cellular immune response rate for cirrhosis patients vs. healthy controls was 0.678 (95% CI, 0.563-0.817, I2 = 0, p < .0001). Our meta-analysis demonstrated that COVID-19 vaccination elicited diminished humoral and cellular immune responses in patients of cirrhosis. Patients with cirrhosis particularly decompensated cirrhosis who have completed full-doses of COVID-19 vaccination should receive continuous attention and preemptive measures.

Clinical development of SpikoGen®, an Advax-CpG55.2 adjuvanted recombinant spike protein vaccine

Recombinant protein vaccines represent a well-established, reliable and safe approach for pandemic vaccination. SpikoGen® is a recombinant spike protein trimer manufactured in insect cells and formulated with Advax-CpG55.2 adjuvant. In murine, hamster, ferret and non-human primate studies, SpikoGen® consistently provided protection against a range of SARS-CoV-2 variants. A pivotal Phase 3 placebo-controlled efficacy trial involving 16,876 participants confirmed the ability of SpikoGen® to prevent infection and severe disease caused by the virulent Delta strain. SpikoGen® subsequently received a marketing authorization from the Iranian FDA in early October 2021 for prevention of COVID-19 in adults. Following a successful pediatric study, its approval was extended to children 5 years and older. Eight million doses of SpikoGen® have been delivered, and a next-generation booster version is currently in development. This highlights the benefits of adjuvanted protein-based approaches which should not overlook when vaccine platforms are being selected for future pandemics.

The association of COVID-19 vaccination and menstrual health: A period-tracking app-based cohort study

Background

In initial COVID-19 clinical trials, menstrual health was not formally monitored, yet anecdotal reports of menstruation changes surfaced on social media. This study aims to assess the association between COVID-19 vaccines and menstruation using Clue, a period-tracking application.

Study design

A survey assessing demographics, menstrual health, stress levels, and COVID-19 vaccination was sent to Clue users between 12/7/2021 and 2/9/2022. Inclusion criteria were (1) 18 years or older (2) currently menstruating (3) not pregnant or breastfeeding since 1/2020. Menstrual data was collected for each participant. Users with cycle lengths more than 90 days were excluded. Cycle lengths were calculated for the 6-month average pre-vaccination (PRIOR), the cycle during which vaccination was administered (DURING), the cycle following DURING (AFTER1), and the cycle following AFTER1 (AFTER2). For periods, individuals were stratified based on whether vaccination was received during their menstrual period (DURING). Period lengths were additionally calculated for the 6-month average pre-vaccination (PRIOR), the first period following vaccination (AFTER1), and the period following AFTER1 (AFTER2). For unvaccinated participants, an index date (4/1/2022) was used to similarly designate menstrual cycles and periods. For each participant, cycle length changes for DURING, AFTER1, and AFTER2 compared to PRIOR were determined. Student's t-test compared the mean of these changes between vaccinated and unvaccinated groups.

Results

Of 7,559 participants, 6,897 (91 %) were vaccinated. Compared to PRIOR, individuals vaccinated during their menstrual period demonstrated a statistically significant increase in the DURING period length, but not AFTER1 (p = 0.463) and AFTER2 (p = 0.692). No statistically significant changes were observed in period lengths of those vaccinated in between periods or in cycle lengths overall.

Conclusion

A small but statistically significant change in period length was observed only in individuals vaccinated for COVID-19 during their menstrual period. Providers can better counsel menstruating individuals to reduce vaccine misinformation.

Vaccine delivery systems and administration routes: Advanced biotechnological techniques to improve the immunization efficacy

Since the first use of vaccine tell the last COVID-19 pandemic caused by spread of SARS-CoV-2 worldwide, the use of advanced biotechnological techniques has accelerated the development of different types and methods for immunization. The last pandemic showed that the nucleic acid-based vaccine, especially mRNA, has an advantage in terms of development time; however, it showed a very critical drawback namely, the higher costs when compared to other strategies, and its inability to protect against new variants. This showed the need of more improvement to reach a better delivery and efficacy. In this review we will describe different vaccine delivery systems including, the most used viral vector, and also variable strategies for delivering of nucleic acid-based vaccines especially lipid-based nanoparticles formulation, polymersomes, electroporation and also the new powerful tools for the delivery of mRNA, which is based on the use of cell-penetrating peptides (CPPs). Additionally, we will also discuss the main challenges associated with each system. Finlay, the efficacy and safety of the vaccines depends not only on the formulations and delivery systems, but also the dosage and route of administration are also important players, therefore we will see the different routes for the vaccine administration including traditionally routes (intramuscular, Transdermal, subcutaneous), oral inhalation or via nasal mucosa, and will describe the advantages and disadvantage of each administration route.

Physical Activity at Different Life Stages and Its Consequence on the Initial Immunization and Inflammatory Response Against COVID-19

BACKGROUND

To evaluate the influence of previous physical activity (PA) during childhood, adolescence, and current PA practice on the production of antibodies and inflammatory response between the first and second doses of the COVID-19 vaccine.

METHODS

Fifty-nine men and 56 women were evaluated before the first vaccine, and 12 weeks later, blood samples were taken to quantify production of anti-severe acute respiratory syndrome coronavirus-2 immunoglobulin G antibodies and cytokines. Previous PA during childhood and adolescence was self-referred, and current PA was assessed using the International Physical Activity Questionnaire.

RESULTS

A positive and significant association was observed only between PA practice during adolescence and an increase in antibody production in adulthood (β = 2012.077, 95% confidence interval, 257.7953-3766.358, P = .025). Individuals who practiced PA during adolescence showed higher production of antibodies between the first and second vaccine dose compared to nonpractitioners (P = .025) and those that accumulated ≥150 minutes per week of current moderate-vigorous PA (MVPA), and presented higher antibody production in relation to who did <150 minutes per week of MVPA (P = .046). Individuals that were practitioners during childhood produced higher G-CSF (P = .047), and those that accumulated ≥150 minutes per week of current MVPA demonstrated lower IP-10 levels (P = .033). However, PA practitioners during adolescence presented higher G-CSF (P = .025), IL-17 (P = .038), IL-1RA (P = .005), IL-1β (P = .020), and IL-2 (P = .026) levels.

CONCLUSION

Our results suggest that adults that accumulated at least 150 minutes of MVPA per week or practiced PA during adolescence developed an improved immune and inflammatory response against COVID-19 vaccination.

Effects of COVID-19 mRNA vaccination on HIV viremia and reservoir size

OBJECTIVE

The immunogenic nature of coronavirus disease 2019 (COVID-19) mRNA vaccines led to some initial concern that these could stimulate the HIV reservoir. We analyzed changes in plasma HIV loads (pVL) and reservoir size following COVID-19 mRNA vaccination in 62 people with HIV (PWH) receiving antiretroviral therapy (ART), and analyzed province-wide trends in pVL before and after the mass vaccination campaign.

DESIGN

Longitudinal observational cohort and province-wide analysis.

METHODS

Sixty-two participants were sampled prevaccination, and one month after their first and second COVID-19 immunizations. Vaccine-induced anti-SARS-CoV-2-Spike antibodies in serum were measured using the Roche Elecsys Anti-S assay. HIV reservoirs were quantified using the intact proviral DNA assay; pVL were measured using the cobas 6800 (lower limit of quantification: 20 copies/ml). The province-wide analysis included all 290 401 pVL performed in British Columbia, Canada between 2012 and 2022.

RESULTS

Prevaccination, the median intact reservoir size was 77 [interquartile range (IQR): 20-204] HIV copies/million CD4 + T-cells, compared to 74 (IQR: 27-212) and 65 (IQR: 22-174) postfirst and -second dose, respectively (all comparisons P > 0.07). Prevaccination, 82% of participants had pVL <20 copies/ml (max: 110 copies/ml), compared to 79% postfirst dose (max: 183 copies/ml) and 85% postsecond dose (max: 79 copies/ml) ( P  > 0.4). There was no evidence that the magnitude of the vaccine-elicited anti-SARS-CoV-2-Spike immune response influenced pVL nor changes in reservoir size ( P  > 0.6). We found no evidence linking the COVID-19 mass vaccination campaign to population-level increases in detectable pVL frequency among all PWH in the province, nor among those who maintained pVL suppression on ART.

CONCLUSION

We found no evidence that COVID-19 mRNA vaccines induced changes in HIV reservoir size nor plasma viremia.

COVID-19 vaccine immunogenicity and safety surrounding fourth and subsequent vaccine doses in patients with hematologic malignancies

BACKGROUND

Immune response to COVID-19 vaccine is diminished in patients with hematologic malignancy. There is limited data regarding response to vaccine doses in these patients.

PURPOSE

To quantify the humoral immune response engendered by 4th and subsequent doses of SARS-CoV-2 vaccination as measured by anti-Spike (anti-S) antibody levels, based on dried blood spot (DBS) testing, in patients with hematologic malignancies. Anti-S binds to the spike protein of the SARS-CoV-2 virus and is indicative of vaccine immunogenicity.

METHODS

We conducted a prospective study of hematologic malignancies between August 2021 and January 2023 at 12 sites across Canada. Participants were followed longitudinally and submitted finger-prick DBS cards at set intervals associated with vaccination. Samples were processed via high throughput ELISA assay to detect serum antibodies against nucleocapsid (N) and spike (S) proteins.

RESULTS

We obtained 3071 samples on 790 unique patients. Of these, 372 unique participants with 1840 samples had anti-S results available post-4th, 5th or 6th COVID-19 vaccine dose and were included for analysis. Three hundred thirty-three patients of the 372 participants submitted a DBS sample post 4th dose. Of these, 257 patients (77.2%) had a positive anti-S antibody. A total of 198 patients had paired samples pre- and post-dose 4, of which 59 (29.7%) had a negative anti-S antibody pre-dose 4. Of these, 20 (33.4%) developed positive anti-S antibody post-dose 4. One hundred forty-nine patients submitted a DBS sample post-dose 5. Of these, 135 patients (90.6%) had positive anti-S antibody. A total of 52 had paired samples pre- and post-dose 5. Six (8.7%) had a negative anti-S antibody pre-dose 5, of which two (33.3%) developed positive anti-S antibody post-dose 5. Of these 372 patients, 123 (34%) reported COVID-19 infection and 4 (1%) had a COVID-19 related hospitalization. There were no reported deaths from COVID-19.

CONCLUSIONS

This prospective cohort study showed that humoral immune response improved with subsequent doses of COVID-19 vaccines.

Systemic prime mucosal boost significantly increases protective efficacy of bivalent RSV influenza viral vectored vaccine

Although licensed vaccines against influenza virus have been successful in reducing pathogen-mediated disease, they have been less effective at preventing viral infection of the airways and current seasonal updates to influenza vaccines do not always successfully accommodate viral drift. Most licensed influenza and recently licensed RSV vaccines are administered via the intramuscular route. Alternative immunisation strategies, such as intranasal vaccinations, and "prime-pull" regimens, may deliver a more sterilising form of protection against respiratory viruses. A bivalent ChAdOx1-based vaccine (ChAdOx1-NP + M1-RSVF) encoding conserved nucleoprotein and matrix 1 proteins from influenza A virus and a modified pre-fusion stabilised RSV A F protein, was designed, developed and tested in preclinical animal models. The aim was to induce broad, cross-protective tissue-resident T cells against heterotypic influenza viruses and neutralising antibodies against RSV in the respiratory mucosa and systemically. When administered via an intramuscular prime-intranasal boost (IM-IN) regimen in mice, superior protection was generated against challenge with either RSV A, Influenza A H3N2 or H1N1. These results support further clinical development of a pan influenza & RSV vaccine administered in a prime-pull regimen.

A gH/gL-encoding replicon vaccine elicits neutralizing antibodies that protect humanized mice against EBV challenge

Epstein-Barr virus (EBV) is associated with several malignancies, neurodegenerative disorders and is the causative agent of infectious mononucleosis. A vaccine that prevents EBV-driven morbidity and mortality remains an unmet need. EBV is orally transmitted, infecting both B cells and epithelial cells. Several virally encoded proteins are involved in entry. The gH/gL glycoprotein complex is essential for infectivity irrespective of cell type, while gp42 is essential for infection of B cells. gp350 promotes viral attachment by binding to CD21 or CD35 and is the most abundant glycoprotein on the virion. gH/gL, gp42 and gp350, are known targets of neutralizing antibodies and therefore relevant immunogens for vaccine development. Here, we developed and optimized the delivery of several alphavirus-derived replicon RNA (repRNA) vaccine candidates encoding gH/gL, gH/gL/gp42 or gp350 delivered by a cationic nanocarrier termed LION™. The lead candidate, encoding full-length gH/gL, elicited high titers of neutralizing antibodies that persisted for at least 8 months and a vaccine-specific CD8+ T cell response. Transfer of vaccine-elicited IgG protected humanized mice from EBV-driven tumor formation and death following high-dose viral challenge. These data demonstrate that LION/repRNA-gH/gL is an ideal candidate vaccine for preventing EBV infection and/or related malignancies in humans.

Pharmacovigilance in Vaccines: Importance, Main Aspects, Perspectives, and Challenges-A Narrative Review

Pharmacovigilance plays a central role in safeguarding public health by continuously monitoring the safety of vaccines, being critical in a climate of vaccine hesitancy, where public trust is paramount. Pharmacovigilance strategies employed to gather information on adverse events following immunization (AEFIs) include pre-registration data, media reports, clinical trials, and societal reporting. Early detection of AEFIs during clinical trials is crucial for thorough safety analysis and preventing serious reactions once vaccines are deployed. This review highlights the importance of societal reporting, encompassing contributions from community members, healthcare workers, and pharmaceutical companies. Technological advancements such as quick response (QR) codes can facilitate prompt AEFI reporting. While vaccines are demonstrably safe, the possibility of adverse events necessitates continuous post-marketing surveillance. However, underreporting remains a challenge, underscoring the critical role of public engagement in pharmacovigilance. This narrative review comprehensively examines and synthesizes key aspects of virus vaccine pharmacovigilance, with special considerations for specific population groups. We explore applicable legislation, the spectrum of AEFIs associated with major vaccines, and the unique challenges and perspectives surrounding pharmacovigilance in this domain.

S2 Peptide-Conjugated SARS-CoV-2 Virus-like Particles Provide Broad Protection against SARS-CoV-2 Variants of Concern

Approved COVID-19 vaccines primarily induce neutralizing antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) protein. However, the emergence of variants of concern with RBD mutations poses challenges to vaccine efficacy. This study aimed to design a next-generation vaccine that provides broader protection against diverse coronaviruses, focusing on glycan-free S2 peptides as vaccine candidates to overcome the low immunogenicity of the S2 domain due to the N-linked glycans on the S antigen stalk, which can mask S2 antibody responses. Glycan-free S2 peptides were synthesized and attached to SARS-CoV-2 virus-like particles (VLPs) lacking the S antigen. Humoral and cellular immune responses were analyzed after the second booster immunization in BALB/c mice. Enzyme-linked immunosorbent assay revealed the reactivity of sera against SARS-CoV-2 variants, and pseudovirus neutralization assay confirmed neutralizing activities. Among the S2 peptide-conjugated VLPs, the S2.3 (N1135-K1157) and S2.5 (A1174-L1193) peptide-VLP conjugates effectively induced S2-specific serum immunoglobulins. These antisera showed high reactivity against SARS-CoV-2 variant S proteins and effectively inhibited pseudoviral infections. S2 peptide-conjugated VLPs activated SARS-CoV-2 VLP-specific T-cells. The SARS-CoV-2 vaccine incorporating conserved S2 peptides and CoV-2 VLPs shows promise as a universal vaccine capable of generating neutralizing antibodies and T-cell responses against SARS-CoV-2 variants.

Randomised, double-blind, controlled phase 1 trial of the candidate tuberculosis vaccine ChAdOx1-85A delivered by aerosol versus intramuscular route

BACKGROUND

A BCG booster vaccination administered via the respiratory mucosa may establish protective immune responses at the primary site of Mycobacterium tuberculosis infection. The primary objective of this trial was to compare the safety and immunogenicity of inhaled versus intramuscular administered ChAdOx1-85A.

METHODS

We conducted a single-centre, randomised, double-blind, controlled phase 1 study (Swiss National Clinical Trials Portal number SNCTP000002920). After a dose-escalation vaccination in nine BCG-vaccinated healthy adults, a dose of 1 × 1010 vp of ChAdOx1-85A was administered to twenty BCG-vaccinated adults that were randomly allocated (1:1) into two groups: aerosol ChAdOx1-85A with intramuscular saline placebo or intramuscular ChAdOx1-85A with aerosol saline placebo, using block randomisation. A control group of ten BCG-naïve adults received aerosol ChAdOx1-85A at the same dose. Primary outcomes were solicited and unsolicited adverse events (AEs) up to day 16 post-vaccination and Serious AEs (SAEs) up to 24 weeks; secondary outcomes were cell-mediated and humoral immune responses in blood and bronchoalveolar lavage (BAL) samples.

FINDINGS

Both vaccination routes were well tolerated with no SAEs. Intramuscular ChAdOx1-85A was associated with more local AEs (mostly pain at the injection site) than aerosol ChAdOx1-85A. Systemic AEs occurred in all groups, mainly fatigue and headaches, without differences between groups. Respiratory AEs were not different between BCG-vaccinated groups. Aerosol ChAdOx1-85A vaccination induced Ag85A BAL and systemic cellular immune responses with compartmentalisation of the immune responses: aerosol ChAdOx1-85A induced stronger BAL cellular responses, particularly IFNγ/IL17+CD4+ T cells; intramuscular ChAdOx1-85A induced stronger systemic cellular and humoral responses.

INTERPRETATION

Inhaled ChAdOx1-85A was well-tolerated and induced lung mucosal and systemic Ag85A-specific T-cell responses. These data support further evaluation of aerosol ChAdOx1-85A and other viral vectors as a BCG-booster vaccination strategy.

The impact of comorbidity status in COVID-19 vaccines effectiveness before and after SARS-CoV-2 omicron variant in northeastern Mexico: a retrospective multi-hospital study

Introduction

The end of the coronavirus disease 2019 (COVID-19) pandemic has been declared by the World Health Organization on May 5, 2023. Several vaccines were developed, and new data is being published about their effectiveness. However, the clinical trials for the vaccines were performed before the Omicron variant appeared and there are population groups where vaccine effectiveness still needs to be tested. The overarching goal of the present study was to analyze the effects of COVID-19 vaccination before and after the Omicron variant in patients considering comorbidities in a population from Nuevo Leon, Mexico.

Methods

Epidemiological COVID-19 data from the Mexican Social Security Institute were collected from 67 hospitals located in northeastern Mexico, from July 2020 to May 2023, and a total of 669,393 cases were compiled, 255,819 reported a SARS-CoV-2 positive reverse transcription quantitative polymerase chain reaction (RT-qPCR) test or a positive COVID-19 antigen rapid test.

Results

Before Omicron (BO, 2020-2021), after 14 days of two doses of COVID-19 vaccine, BNT162b2 and ChAdOx1 vaccines were effective against infection in non-comorbid and all comorbid subgroups, whereas after Omicron (AO, 2022- 2023) there was no significant effectiveness against infection with none of the vaccines. Regarding hospitalization BO, BNT162b2, ChAdOx1, CoronaVac and mRNA-1273 significantly protected non-comorbid patients whereas BNT162b2, ChAdOx1, and mRNA-1273, protected all comorbid subgroups against hospitalization. AO, BNT162b2, ChAdOx1, CoronaVac and mRNA-1273 were effective against hospitalization in non-comorbid patients whereas for most comorbid subgroups BNT162b2, ChAdOx1 and CoronaVac were effective against hospitalization. Non-comorbid patients were protected against death as an outcome of COVID-19 during the BO period with most vaccines whereas a reduction in effectiveness was observed AO with mRNA-1273 vaccines in patients with hypertension, and diabetes mellitus.

Discussion

BO, COVID-19 vaccines were effective against infection, hospitalization, and death whereas AO, COVID-19 vaccines failed to protect the population from COVID-19 infection. A varying effectiveness against hospitalization and death is observed AO.

A qualitative examination of the experiences and perspectives of interprofessional primary health care teams in the distribution of the COVID-19 vaccination in Ontario, Canada

BACKGROUND

Primary health care (PHC) teams contributed to all phases of the COVID-19 vaccination distribution. However, there has been criticism for not fully utilizing the expertise and infrastructure of PHC teams for vaccination distribution. Our study sought to understand the role PHC teams had in the distribution of the COVID-19 vaccine in Ontario, Canada. The key objective informing this study was to explore the experiences and perspectives of interprofessional PHC teams in the distribution of COVID-19 vaccination across Ontario.

METHODS

A qualitative approach was used for this study, which involved 39 participants from the six health regions of the province. Eight focus groups were conducted with a range of interprofessional healthcare providers, administrators, and staff working in PHC teams across Ontario. The sample reflected a diverse range of clinical, administrative, and leadership roles in PHC. Focus groups were audio-recorded and transcribed, while transcriptions were then analyzed using thematic analysis.

RESULTS

We identified the following four themes in the data: i) PHC teams know their patients; ii) mobilizing team capacity for vaccination, iii) intersectoral collaborations, and iv) operational challenges.

CONCLUSIONS

PHC teams were an instrumental component in supporting COVID-19 vaccinations in Ontario. The involvement of PHC in future vaccination efforts is key but requires additional resourcing and inclusion of PHC in decision-making. This will ensure provider well-being and maintain collaborations established during COVID-19 vaccination.

Effect of Prior ChAdOx1 COVID-19 Immunisation on T-Cell Responses to ChAdOx1-HBV

There are varying data concerning the effect of prior anti-vector immunity on the T-cell response induced by immunisation with an identical vectored vaccine containing a heterologous antigen insert. To determine whether prior exposure to ChAdOx1-SARS-CoV2 immunisation (Vaxzevria®) impacts magnitudes of antigen-specific T-cell responses elicited by subsequent administration of the same viral vector (encoding HBV antigens, ChAdOx1-HBV), healthy volunteers that had received Vaxzevria® (n = 15) or the Pfizer or Moderna mRNA COVID-19 vaccine (n = 11) between 10 and 18 weeks prior were recruited to receive a single intramuscular injection of ChAdOx1-HBV. Anti-ChAdOx1-neutralising antibody titers were determined, and vector or insert-specific T-cell responses were measured by a gamma-interferon ELISpot and intracellular cytokine staining (ICS) assay using multiparameter flow cytometry. Participants were followed for three months after the ChAdOx1-HBV injection, which was well-tolerated, and no dropouts occurred. The baseline ChAdOx1 neutralisation titers were higher in the Vaxzevria® cohort (median of 848) than in the mRNA cohort (median of 25). T-cell responses to HBV antigens, measured by ELISpot, were higher on day 28 in the mRNA group (p = 0.013) but were similar between groups on day 84 (p = 0.441). By ICS, these differences persisted at the last time point. There was no clear correlation between the baseline responses to the adenoviral hexon and the subsequent ELISpot responses. As vaccination within 3 months using the same viral vector backbone affected the insert-specific T-cell responses, a greater interval after prior adenoviral immunisation using heterologous antigens may be warranted in settings in which these cells play critical roles.

A natural experiment during lockdown and on-going care-home COVID-19 outbreaks showed a single dose of vaccine reduced hospitalisation and deaths of care-home residents in North West England

OBJECTIVE

To examine the effectiveness of one dose of the COVID-19 vaccine on care-home residents.

STUDY DESIGN

Natural experiment.

METHODS

We compared the effectiveness of single doses of Pfizer/BioNTech BNT162b2 (effective at 10 days) and AstraZeneca ChAdOx1 (effective at 14 days) vaccines in vaccinated and control (unvaccinated) homes. Using routine data, all care-homes reporting COVID-19 outbreaks between 11/12/2020 and 12/3/2021 in a sub-region of North West England were included.

RESULTS

Of 126 care-homes (4042 residents), with outbreaks, 55 (44%, 1686 residents) reported onset dates before vaccination commenced; 38 (30%, 1304 residents) reported onset < 10 (BNT162b2) and < 14 days (ChAdOx1) after vaccine administration; and 33 (26%, 1052 residents) reported onset > 10 (BNT162b2) and > 14 (ChAdOx1) days after vaccination. Eighty-nine (71%) homes used ChAdOx1 vaccine. A single dose of vaccine before the outbreak onset significantly lowered the risk of symptoms (reduced by 48%), positivity (by 65%), hospitalisation (by 68%), and death (by 81%). Some vaccine effectiveness was also noted in care-homes that received one dose of vaccine within 10-14 days of outbreak onset. The number needed to vaccinate to prevent one resident from COVID-19-related hospitalisation was 34, and death was 17.

CONCLUSIONS

This real-world, natural experiment adds to the evidence of COVID-19 vaccine effectiveness from different studies using varying designs. In the context of lockdown's impact on infection rates and on-going care-home outbreaks, a single dose of either ChAdOx1 or BNT162b2 vaccine had a significant impact on reducing COVID-19 related hospitalisation and death in care-home residents. Natural experiments should be used more in public health.

Identification of cross reactive T cell responses in adenovirus based COVID 19 vaccines

Vaccination has proven to be a valuable tool to combat SARS-CoV-2. However, reports of rare adverse reactions such as thrombosis/thrombocytopenia syndrome after ChAdOx1 nCoV-19 vaccination have caused scientific, public and media concern. ChAdOx1 was vectorised from the Y25 chimpanzee adenovirus, which was selected due to low human seroprevalence to circumvent pre-existing immunity. In this study, we aimed to explore patterns of T-cell activation after SARS-CoV-2 COVID-19 vaccine exposure in vitro using PBMCs collected from pre-pandemic ChAdOx1 nCoV-19 naïve healthy donors (HDs), and ChAdOx1 nCoV-19 and Pfizer vaccinated controls. PBMCs were assessed for T-cell proliferation using the lymphocyte transformation test (LTT) following exposure to SARS-CoV-2 COVID-19 vaccines. Cytokine analysis was performed via intracellular cytokine staining, ELISpot assay and LEGENDplex immunoassays. T-cell assays performed in pre-pandemic vaccine naïve HDs, revealed widespread lymphocyte stimulation after exposure to ChAdOx1 nCoV-19 (95%), ChAdOx-spike (90%) and the Ad26.COV2. S vaccine, but not on exposure to the BNT162b2 vaccine. ICS analysis demonstrated that CD4+ CD45RO+ memory T-cells are activated by ChAdOx1 nCoV-19 in vaccine naïve HDs. Cytometric immunoassays showed ChAdOx1 nCoV-19 exposure was associated with the release of proinflammatory and cytotoxic molecules, such as IFN-γ, IL-6, perforin, granzyme B and FasL. These studies demonstrate a ubiquitous T-cell response to ChAdOx1 nCoV-19 and Ad26.COV2. S in HDs recruited prior to the SARS-CoV-2 pandemic, with T-cell stimulation also identified in vaccinated controls. This may be due to underlying T-cell cross-reactivity with prevalent human adenoviruses and further study will be needed to identify T-cell epitopes involved.

New insights into kidney disease after COVID-19 infection and vaccination: histopathological and clinical findings

In addition to its pulmonary effects, coronavirus disease 2019 (COVID-19) has also been found to cause acute kidney injury (AKI), which has been linked to high mortality rates. In this review, we collected data from 20 clinical studies on post-COVID-19-related AKI and 97 cases of AKI associated with COVID-19 vaccination. Acute tubular injury was by far the most common finding in the kidneys of patients with COVID-19-related AKI. Among patients hospitalized for COVID-19, 34.0% developed AKI, of which 59.0%, 19.1% and 21.9% were Stages 1, 2 and 3, respectively. Though kidney disease and other adverse effects after COVID-19 vaccination overall appear rare, case reports have accumulated suggesting that COVID-19 vaccination may be associated with a risk of subsequent kidney disease. Among the patients with post-vaccination AKI, the most common pathologic findings include crescentic glomerulonephritis (29.9%), acute tubular injury (23.7%), IgA nephropathy (18.6%), antineutrophil cytoplasmic autoantibody-associated vasculitis (17.5%), minimal change disease (17.5%) and thrombotic microangiopathy (10.3%). It is important to note that crescentic glomerulonephritis appears to be more prevalent in patients who have newly diagnosed renal involvement. The proportions of patients with AKI Stages 1, 2 and 3 after COVID-19 vaccination in case reports were 30.9%, 22.7% and 46.4%, respectively. In general, clinical cases of new-onset and recurrent nephropathy with AKI after COVID-19 vaccination have a positive prognosis. In this article, we also explore the underlying pathophysiological mechanisms of AKI associated with COVID-19 infection and its vaccination by describing key renal morphological and clinical features and prognostic findings.

Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection by Type and Frequency of Vaccine: A Community-Based Case-Control Study

BACKGROUND

Although guidelines recommend vaccination for individuals who have recovered from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to prevent reinfection, comprehensive evaluation studies are limited. We aimed to evaluate vaccine effectiveness against SARS-CoV-2 reinfection according to the primary vaccination status, booster vaccination status, and vaccination methods used.

METHODS

This population-based case-control study enrolled all SARS-CoV-2-infected patients in Seoul between January 2020 and February 2022. Individuals were categorized into case (reinfection) and control (no reinfection) groups. Data were analyzed using conditional logistic regression after adjusting for underlying comorbidities using multiple regression.

RESULTS

The case group included 7,678 participants (average age: 32.26 years). In all vaccinated individuals, patients who received the first and second booster doses showed reduced reinfection rates compared with individuals who received basic vaccination (odds ratio [OR] = 0.605, P < 0.001 and OR = 0.002, P < 0.001). Patients who received BNT162b2 or mRNA-1273, NVX-CoV2373 and heterologous vaccination showed reduced reinfection rates compared with unvaccinated individuals (OR = 0.546, P < 0.001; OR = 0.356, P < 0.001; and OR = 0.472, P < 0.001). However, the ChAdOx1-S or Ad26.COV2.S vaccination group showed a higher reinfection rate than the BNT162b2 or mRNA-1273 vaccination group (OR = 4.419, P < 0.001).

CONCLUSION

In SARS-CoV-2-infected individuals, completion of the basic vaccination series showed significant protection against reinfection compared with no vaccination. If the first or second booster vaccination was received, the protective effect against reinfection was higher than that of basic vaccination; when vaccinated with BNT162b2 or mRNA-1273 only or heterologous vaccination, the protective effect was higher than that of ChAdOx1-S or Ad26.COV2.S vaccination only.

Incidence and management of the main serious adverse events reported after COVID-19 vaccination

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2n first appeared in Wuhan, China in 2019. Soon after, it was declared a pandemic by the World Health Organization. The health crisis imposed by a new virus and its rapid spread worldwide prompted the fast development of vaccines. For the first time in human history, two vaccines based on recombinant genetic material technology were approved for human use. These mRNA vaccines were applied in massive immunization programs around the world, followed by other vaccines based on more traditional approaches. Even though all vaccines were tested in clinical trials prior to their general administration, serious adverse events, usually of very low incidence, were mostly identified after application of millions of doses. Establishing a direct correlation (the cause-effect paradigm) between vaccination and the appearance of adverse effects has proven challenging. This review focuses on the main adverse effects observed after vaccination, including anaphylaxis, myocarditis, vaccine-induced thrombotic thrombocytopenia, Guillain-Barré syndrome, and transverse myelitis reported in the context of COVID-19 vaccination. We highlight the symptoms, laboratory tests required for an adequate diagnosis, and briefly outline the recommended treatments for these adverse effects. The aim of this work is to increase awareness among healthcare personnel about the serious adverse events that may arise post-vaccination. Regardless of the ongoing discussion about the safety of COVID-19 vaccination, these adverse effects must be identified promptly and treated effectively to reduce the risk of complications.

A new framework for developing and evaluating complex interventions: update of Medical Research Council guidance

The UK Medical Research Council's widely used guidance for developing and evaluating complex interventions has been replaced by a new framework, commissioned jointly by the Medical Research Council and the National Institute for Health Research, which takes account of recent developments in theory and methods and the need to maximise the efficiency, use, and impact of research.

Optimization and validation of a virus-like particle pseudotyped virus neutralization assay for SARS-CoV-2

Spike-protein-based pseudotyped viruses were used to evaluate vaccines during the COVID-19 pandemic. However, they cannot be used to evaluate the envelope (E), membrane (M), and nucleocapsid (N) proteins. The first generation of virus-like particle (VLP) pseudotyped viruses contains these four structural proteins, but their titers for wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are relatively low, even lower for the omicron variant, rendering them unsuitable for neutralizing antibody detection. By optimizing the spike glycoprotein signal peptide, substituting the complexed M and E proteins with SARS-COV-1, optimizing the N protein with specific mutations (P199L, S202R, and R203M), and truncating the packaging signal, PS9, we increased the titer of the wild-type VLP pseudotyped virus over 100-fold, and successfully packaged the omicron VLP pseudotyped virus. The SARS-CoV-2 VLP pseudotyped viruses maintained stable titers, even through 10 freeze-thaw cycles. The key neutralization assay parameters were optimized, including cell type, cell number, and viral inoculum. The assay demonstrated minimal variation in both intra- and interassay results, at 11.5% and 11.1%, respectively. The correlation between the VLP pseudotyped virus and the authentic virus was strong (r = 0.9). Suitable for high-throughput detection of various mutant strains in clinical serum. In summary, we have developed a reliable neutralization assay for SARS-CoV-2 based on VLP pseudotyped virus.

Association of New-Onset Seizures With SARS-CoV-2 Vaccines: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Importance

Seizures have been reported as an adverse effect of the SARS-CoV-2 vaccine. However, no study has answered the question of whether there is any association between seizures in the general population and COVID-19 vaccination.

Objective

To evaluate the seizure incidence among SARS-CoV-2 vaccine recipients compared with those who received a placebo.

Data Sources

A systematic search of MEDLINE (via PubMed), Web of Science, Scopus, Cochrane Library, Google Scholar, review publications, editorials, letters to editors, and conference papers, along with the references of the included studies from December 2019 to July 7, 2023.

Study Selection

Randomized clinical trials (RCTs) reporting seizure incidence with SARS-CoV-2 vaccination were included.

Data Extraction and Synthesis

This study is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework and used the Mantel-Haenszel method with random- and common-effect models. The risk of bias of the studies was assessed using the Cochrane assessment tool for RCTs.

Main Outcomes and Measures

The outcome of interest was new-onset seizure incidence proportion compared among (1) SARS-CoV-2 vaccine recipients and (2) placebo recipients.

Results

Six RCTs were included in the study. Results of the pooled analysis comparing the incidence of new-onset seizure between the 63 521 vaccine and 54 919 placebo recipients in the 28-day follow-up after vaccine/placebo injection showed no statistically significant difference between the 2 groups (9 events [0.014%] in vaccine and 1 event [0.002%] in placebo recipients; odds ratio [OR], 2.70; 95% CI, 0.76-9.57; P = .12; I2 = 0%, τ2 = 0, Cochran Q P = .74). Likewise, in the entire blinded-phase period after injection, with a median of more than 43 days, no significant difference was identified between the vaccine and placebo groups regarding incident new-onset seizure (13/43 724 events [0.03%] in vaccine and 5/40 612 [0.012%] in placebo recipients; OR, 2.31; 95% CI, 0.86-6.23, P = .10, I2 = 0%, τ2 = 0, Cochran Q P = .95).

Conclusions and Relevance

According to this systematic review and meta-analysis, there was no statistically significant difference in the risk of new-onset seizure incidence between vaccinated individuals and placebo recipients.

Autoimmune adverse event following COVID-19 vaccination in Seoul, South Korea

BACKGROUND

There is growing evidence that the coronavirus disease 2019 (COVID-19) vaccination can affect the regulation of the immune system, leading to the development of autoimmune diseases. However, the autoimmune adverse events (AEs) after COVID-19 vaccination remain largely unclear.

OBJECTIVE

We sought to investigate the autoimmune AEs after COVID-19 vaccination from a population-based cohort in South Korea.

METHODS

A total of 4,203,887 participants, representing 50% of the population residing in Seoul, were recruited from the National Health Insurance Service database and then divided into 2 groups on the basis of COVID-19 vaccination. The cumulative incidence, hazard ratios (HRs), and 95% CIs of autoimmune AEs were assessed following COVID-19 vaccination.

RESULTS

The incidence of vitiligo has been observed to be significantly higher in the vaccination group compared with the no vaccination group. The cumulative incidence of vitiligo began to show a significant difference starting 2 weeks after vaccination, and it reached 2.2% in the vaccination group and 0.6% in the no vaccination group by 3 months after COVID-19 vaccination. Vitiligo (HR, 2.714; 95% CI, 1.777-4.146) was an increased risk among autoimmune AEs. Furthermore, the risk of vitiligo was the highest for heterologous vaccination (HR, 3.890; 95% CI, 2.303-6.573) compared with using cDNA vaccine (HR, 2.861; 95% CI, 1.838-4.453) or mRNA vaccine (HR, 2.475; 95% CI, 1.607-3.813).

CONCLUSIONS

Vitiligo as an autoimmune AE was noted to be substantially higher in the COVID-19-vaccinated group compared with the controls. Therefore, the occurrence of vitiligo could be considered as one of the significant AEs post-COVID-19 vaccination.

SARS-CoV-2 spike protein expression as an identification in quality control testing for Adenovector based COVID-19 vaccine

AIM

Quality control testing of the vaccine for lot release is of paramount importance in public health. A recent pandemic caused by the SARS-CoV-2 virus brought together all spheres of vaccine to combat the virus. The scientific advancement in the development of vaccines facilitated the scientists to develop the vaccine against SARS-CoV-2 in a record time. Thus, these vaccines should be stringently monitored for their safety and efficacy as per the latest WHO and national regulatory guidelines, and quality control evaluation of the product should be done at national control laboratories before releasing the product into the market as it assures the quality and safety of the vaccine.

METHODS

The SARS-CoV-2 exploited the ACE2 (Angiotensin Converting Enzyme 2) receptor, a surface protein on mammalian cells to gain entry into the host cells. The viral surface protein that interacted with the ACE2 receptor is the Spike protein of SARS-CoV-2. Thus, in the development of the vaccine and assessing its quality, the Spike protein of SARS-CoV-2 became an attractive immunodominant antigen. In National Institute of Biologicals, an apex body in the testing of biologicals in India, received the Adenovector (Adenovirus + vector) based COVID-19 vaccine, a finished product for quality evaluation. Due to the lack of a pharmacopeial monograph, the testing of the vaccine was done as per the manufacturer's specifications and methods. The routine assays of identification employed by the manufacturer do not reflect the expression of Spike protein which is required for the immune system to get activated. In this report, we showed the determination of Spike protein expression by immunoblotting and immunofluorescence for identification parameters in the quality testing of the COVID-19 vaccine. We determined the translation of the SARS-CoV-2 Spike gene cloned into an Adenovector.

RESULTS

The results from these experiments indicated the expression of Spike protein upon infection of mammalian cells with viral particles suggested that the expression of immunodominant Spike protein of SARS-CoV-2 may be employed by quality control laboratories as a parameter for identification.

CONCLUSION

The study suggested that the determination of the expression of Spike protein is pertinent to identifying the Adenovector based vaccines against COVID-19.

Ischemic and Inflammatory Ocular Adverse Events Following Different Types of Vaccination for COVID-19 and Their Incidence Analysis

PURPOSE

To evaluate the ocular adverse event (OAE) and the incidence rate that can occur after the COVID-19 vaccination.

METHODS

Patients who visited with an ophthalmologic diagnosis within a month of COVID-19 vaccination were retrospectively analyzed. OAEs were categorized as ischemia and inflammation by their presumed pathogenesis and were compared by types of vaccine: messenger RNA (mRNA) and viral vector vaccine. The crude incidence rate was calculated using data from the Korea Disease Control and Prevention Agency.

RESULTS

Twenty-four patients with OAEs after COVID-19 vaccination were reviewed: 10 patients after mRNA and 14 after viral vector vaccine. Retinal vein occlusion (nine patients) and paralytic strabismus (four patients) were the leading diagnoses. Ischemic OAE was likely to occur after viral vector vaccines, while inflammatory OAE was closely related to mRNA vaccine (p = 0.017). The overall incidence rate of OAE was 5.8 cases per million doses: 11.5 per million doses in viral vector vaccine and 3.4 per million doses in mRNA vaccine.

CONCLUSIONS

OAEs can be observed shortly after the COVID-19 vaccination, and their category was different based on the types of vaccine. The information and incidence of OAE based on the type of vaccine can help monitor patients who were administered the COVID-19 vaccine.

COVID-19 vaccine hesitancy prevalence in Mexico: A systematic review and metanalysis

Background

Vaccine hesitancy (VH) is a recognized threat to public health that undermines efforts to mitigate disease burden. This study aims to gather available evidence regarding COVID-19 VH in Mexico, estimate the prevalence of VH, and its determinants to inform policymaking in this country.

Methods

Following PRISMA guidelines, a systematic review of the MEDLINE literature, articles that estimated the prevalence of COVID-19 VH in Mexico were included in the analysis to obtain a pooled estimate. We used a binomial-normal model for meta-analysis of proportions (i.e., generalized linear mixed model) to perform the metanalysis. We then performed a narrative review of COVID-19 VH in Mexican subpopulations.

Results

Seven studies met inclusion criteria. We estimated a pooled prevalence of COVID-19 VH of 16 % (95 % CI: 11-23 %) in Mexico. We found an association between VH and demographic characteristics, intrinsic vaccine factors, and beliefs. Subgroup analyses from specific studies suggested that patients with clinical conditions such as breast cancer or rheumatologic diseases had a higher prevalence of VH.

Conclusions

VH is a highly complex and dynamic phenomenon in Mexico. Characterizing and understanding COVID-19 vaccine hesitancy in the Mexican population helps target future policy interventions to mitigate the spread and impact of infectious diseases. The implications of VH differ among groups that may be at higher risk of severe disease, underscoring the importance of prompt research among these groups as well as targeted interventions to address VH.

E4orf1: The triple agent of adenovirus - Unraveling its roles in oncogenesis, infectious obesity and immune responses in virus replication and vector therapy

Human Adenoviruses (HAdV) are nearly ubiquitous pathogens comprising numerous sub-types that infect various tissues and organs. Among many encoded proteins that facilitate viral replication and subversion of host cellular processes, the viral E4orf1 protein has emerged as an intriguing yet under-investigated player in the complex interplay between the virus and its host. E4orf1 has gained attention as a metabolism activator and oncogenic agent, while recent research is showing that E4orf1 may play a more important role in modulating cellular pathways such as PI3K-Akt-mTOR, Ras, the immune response and further HAdV replication stages than previously anticipated. In this review, we aim to explore the structure, molecular mechanisms, and biological functions of E4orf1, shedding light on its potentially multifaceted roles during HAdV infection, including metabolic diseases and oncogenesis. Furthermore, we discuss the role of functional E4orf1 in biotechnological applications such as Adenovirus (AdV) vaccine vectors and oncolytic AdV. By dissecting the intricate relationships between HAdV types and E4orf1 proteins, this review provides valuable insights into viral pathogenesis and points to promising areas of future research.

The presence of broadly neutralizing anti-SARS-CoV-2 RBD antibodies elicited by primary series and booster dose of COVID-19 vaccine

Antibody-mediated immunity plays a key role in protection against SARS-CoV-2. We characterized B-cell-derived anti-SARS-CoV-2 RBD antibody repertoires from vaccinated and infected individuals and elucidate the mechanism of action of broadly neutralizing antibodies and dissect antibodies at the epitope level. The breadth and clonality of anti-RBD B cell response varies among individuals. The majority of neutralizing antibody clones lose or exhibit reduced activities against Beta, Delta, and Omicron variants. Nevertheless, a portion of anti-RBD antibody clones that develops after a primary series or booster dose of COVID-19 vaccination exhibit broad neutralization against emerging Omicron BA.2, BA.4, BA.5, BQ.1.1, XBB.1.5 and XBB.1.16 variants. These broadly neutralizing antibodies share genetic features including a conserved usage of the IGHV3-53 and 3-9 genes and recognize three clustered epitopes of the RBD, including epitopes that partially overlap the classically defined set identified early in the pandemic. The Fab-RBD crystal and Fab-Spike complex structures corroborate the epitope grouping of antibodies and reveal the detailed binding mode of broadly neutralizing antibodies. Structure-guided mutagenesis improves binding and neutralization potency of antibody with Omicron variants via a single amino-substitution. Together, these results provide an immunological basis for partial protection against severe COVID-19 by the ancestral strain-based vaccine and indicate guidance for next generation monoclonal antibody development and vaccine design.

Analysis of Allergy and Hypersensitivity Reactions to COVID-19 Vaccines According to the EudraVigilance Database

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic presented a new challenge in modern medicine: the development of vaccines was followed by massive population vaccinations. A few reports on post-vaccination allergic reactions have made patients and medical personnel uneasy as to COVID-19 vaccines' allergic potential. Most of the studies in this area to date have been small, and some that were based on global databases skipped most of the allergic diseases and concentrated only on anaphylaxis. We aimed to analyze the incidence of serious allergic reactions based on the EudraVigilance (EV) database, regardless of the reported symptoms and allergy mechanism.

METHODS

The total number of administrated vaccine doses was extracted on 5 October 2023 from Vaccine Tracker and included all administrations since vaccinations began in the European Economic Area (EEA). Data on serious allergic reactions to COVID-19 vaccines were extracted from the EudraVigilance database with the same time point. The code names of 147 allergic symptoms or diseases were used.

RESULTS

The frequency of serious allergic reactions per 100,000 administered vaccine doses was 1.53 for Comirnaty, 2.16 for Spikevax, 88.6 for Vaxzevria, 2.11 for Janssen, 7.9 for Novavax, 13.3 for VidPrevtyn Beta, and 3.1 for Valneva. The most prevalent reported reactions were edema (0.46) and anaphylaxis (0.40). Only 6% of these reactions were delayed hypersensitivity-oriented.

CONCLUSIONS

The overall frequency of potential serious allergic reactions to COVID-19 is very rare. Therefore, COVID-19 vaccines seem to be safe for human use. The lowest frequency of allergic reaction was observed for Comirnaty and the highest for Vaxzevria.

Incidence and Outcomes of COVID-19 Vaccine Hypersensitivity Reactions and Success of COVID-19 Vaccine Provocation Tests Post Previous COVID-19 Vaccine Hypersensitivity

Background: The COVID-19 pandemic has led to high mortality rates. There have been reports of hypersensitivity reactions with mild to severe symptoms. The COVID-19 vaccine provocation test is a vaccination protocol for individuals with a history of hypersensitivity. This study aims to determine the benefits of COVID-19 vaccine provocation tests in patients with a history of hypersensitivity reactions to COVID-19 vaccines and its influencing factors. Objective: To determine the incidence, severity, outcome of hypersensitivity reactions, and success of the COVID-19 vaccine provocation test. Methods: A retrospective cohort study was conducted, using subjects taken from medical record data at the RSCM who had received COVID-19 vaccination with a history of hypersensitivity. Data was taken from the COVID-19 vaccination records at the RSCM, BPJS Health Primary Care application. Results: From a total of 29,036 doses of the COVID-19 vaccine, 44 patients experienced hypersensitivity reactions. As many as 38.64% did not continue vaccination, 2.27% experienced mild hypersensitivity, and 59.44% were successfully vaccinated. Conclusions: People with a history of hypersensitivity reactions to COVID-19 vaccines can still receive subsequent COVID-19 vaccinations at healthcare facilities equipped with anaphylaxis kits and immunology allergists.

Influence of individuals' determinants including vaccine type on cellular and humoral responses to SARS-CoV-2 vaccination

Vaccine development targeting SARS-CoV-2 in 2020 was of critical importance in reducing COVID-19 severity and mortality. In the U.K. during the initial roll-out most individuals either received two doses of Pfizer COVID-19 vaccine (BNT162b2) or the adenovirus-based vaccine from Oxford/AstraZeneca (ChAdOx1-nCoV-19). There are conflicting data as to the impact of age, sex and body habitus on cellular and humoral responses to vaccination, and most studies in this area have focused on determinants of mRNA vaccine immunogenicity. Here, we studied a cohort of participants in a population-based longitudinal study (COVIDENCE UK) to determine the influence of age, sex, body mass index (BMI) and pre-vaccination anti-Spike (anti-S) antibody status on vaccine-induced humoral and cellular immune responses to two doses of BNT162b2 or ChAdOx-n-CoV-19 vaccination. Younger age and pre-vaccination anti-S seropositivity were both associated with stronger antibody responses to vaccination. BNT162b2 generated higher neutralising and anti-S antibody titres to vaccination than ChAdOx1-nCoV-19, but cellular responses to the two vaccines were no different. Irrespective of vaccine type, increasing age was also associated with decreased frequency of cytokine double-positive CD4+T cells. Increasing BMI was associated with reduced frequency of SARS-CoV-2-specific TNF+CD8% T cells for both vaccines. Together, our findings demonstrate that increasing age and BMI are associated with attenuated cellular and humoral responses to SARS-CoV-2 vaccination. Whilst both vaccines induced T cell responses, BNT162b2 induced significantly elevated humoral immune response as compared to ChAdOx-n-CoV-19.

SARS-CoV-2 Neutralization Assays Used in Clinical Trials: A Narrative Review

Since the emergence of COVID-19, extensive research efforts have been undertaken to accelerate the development of multiple types of vaccines to combat the pandemic. These include inactivated, recombinant subunit, viral vector, and nucleic acid vaccines. In the development of these diverse vaccines, appropriate methods to assess vaccine immunogenicity are essential in both preclinical and clinical studies. Among the biomarkers used in vaccine evaluation, the neutralizing antibody level serves as a pivotal indicator for assessing vaccine efficacy. Neutralizing antibody detection methods can mainly be classified into three types: the conventional virus neutralization test, pseudovirus neutralization test, and surrogate virus neutralization test. Importantly, standardization of these assays is critical for their application to yield results that are comparable across different laboratories. The development and use of international or regional standards would facilitate assay standardization and facilitate comparisons of the immune responses induced by different vaccines. In this comprehensive review, we discuss the principles, advantages, limitations, and application of different SARS-CoV-2 neutralization assays in vaccine clinical trials. This will provide guidance for the development and evaluation of COVID-19 vaccines.

SARS-CoV-2-Specific Antibodies, B Cell and T Cell Immune Responses after ChAdOx1 nCoV-19 Vaccination in Solid Organ Transplant Recipients

BACKGROUND

Immunization against SARS-CoV-2 is essential for vulnerable solid organ transplant (SOT) recipients who are at risk of infection. However, there are concerns about suboptimal immunogenicity, especially in humoral immunity (HMI), and limited exploration of cell-mediated immune (CMI) responses. The primary objective of this study was to assess the immunogenicity of ChAdOx1 nCoV-19 vaccination in SOT recipients. The secondary endpoint was to evaluate factors that affect immunogenicity and adverse events (AEs) following immunization in SOT recipients.

METHODS

All adult SOT recipients who received the two-dose ChAdOx1 nCoV-19 vaccine at a 12-week interval underwent measurements of HMI by evaluating anti-receptor-binding domain (RBD) IgG levels and CMI by investigating SARS-CoV-2-specific T cell and B cell responses before and after complete vaccination, around 2-4 weeks post-vaccination, and compared to controls. AEs were monitored in all participants.

RESULTS

The study included 63 SOT recipients: 44 kidney recipients, 16 liver recipients, and 3 heart transplant recipients, along with 11 immunocompetent controls. Among SOT recipients, 36% were female, and the median (IQR) age was 52 (42-61). The median (IQR) time since transplant was 55 (28-123) months. After the second dose, the median (IQR) anti-RBD antibody levels were significantly lower in SOT recipients compared to those in the control group (8.3 [0.4-46.0] vs. 272.2 [178.1-551.6] BAU/mL, p < 0.01). This resulted in a seroconversion rate (anti-RBD antibody > 7.1 BAU/mL) of 51% among SOT recipients and 100% among controls (p = 0.008). Receiving the vaccine beyond one year post-transplant significantly affected seroconversion (OR 9.04, 95% CI 1.04-78.56, p = 0.046), and low-dose mycophenolic acid marginally affected seroconversion (OR 2.67, 95% CI 0.89-7.96, p = 0.079). RBD-specific B cell responses were also significantly lower compared to those in the control group (0 [0-4] vs. 10 [6-22] SFUs/106 PBMCs, p = 0.001). Similarly, S1- and SNMO-specific T cell responses were significantly lower compared to those in the control group (48 [16-128] vs. 216 [132-356] SFUs/106 PBMCs, p = 0.004 and 20 [4-48] vs. 92 [72-320] SFUs/106 PBMCs, p = 0.004). AEs were generally mild and spontaneously resolved.

CONCLUSIONS

SOT recipients who received the full two-dose ChAdOx1 nCoV-19 vaccine demonstrated significantly diminished HMI and CMI responses compared to immunocompetent individuals. Consideration should be given to administering additional vaccine doses or optimizing immunosuppressant regimens during vaccination (Thai Clinical Trial Registry: TCTR20210523002).

COVID-19 Vaccines in the Pediatric Population: A Focus on Cardiac Patients

Due to the deleterious global impact of the COVID-19 pandemic, tremendous effort has been invested in the development of vaccines against the virus. Vaccine candidates are first tested in adult populations, a number of which have been approved for EUL by the WHO, and are in use across the USA and MENA region. The question remains whether these (or other) vaccines should be recommended to a neonatal, pediatric, and/or adolescent cohort. Incidence and severity of COVID-19 infection are low in pediatric, neonatal, and adolescent patients. Since both overall incidence and severity are lower in children than in adults, safety is an important consideration in vaccine approval for these age groups, in addition to efficacy and a decreased risk of transmission. The following review discusses vaccine immunology in children aged 0-18 years, with emphasis on the negative impact of the COVID-19 pandemic on the lives of children, considerations for pediatric vaccine approval, and available vaccines for pediatric cohorts along with a breakdown of the efficacy, advantages, and disadvantages for each. This review also contains current and future perspectives, as well as a section on the cardiovascular implications and related dynamics of pediatric COVID-19 vaccination.

Expanding the adenovirus toolbox: reporter viruses for studying the dynamics of human adenovirus replication

To streamline standard virological assays, we developed a suite of nine fluorescent or bioluminescent replication competent human species C5 adenovirus reporter viruses that mimic their parental wild-type counterpart. These reporter viruses provide a rapid and quantitative readout of various aspects of viral infection and replication based on EGFP, mCherry, or NanoLuc measurement. Moreover, they permit real-time non-invasive measures of viral load, replication dynamics, and infection kinetics over the entire course of infection, allowing measurements that were not previously possible. This suite of replication competent reporter viruses increases the ease, speed, and adaptability of standard assays and has the potential to accelerate multiple areas of human adenovirus research.IMPORTANCEIn this work, we developed a versatile toolbox of nine HAdV-C5 reporter viruses and validated their functions in cell culture. These reporter viruses provide a rapid and quantitative readout of various aspects of viral infection and replication based on EGFP, mCherry, or NanoLuc measurement. The utility of these reporter viruses could also be extended for use in 3D cell culture, organoids, live cell imaging, or animal models, and provides a conceptual framework for the development of new reporter viruses representing other clinically relevant HAdV species.

Factors associated with willingness to receive coronavirus disease vaccination during the pandemic: A nationwide survey in Taiwan

BACKGROUND/PURPOSE

Vaccination is the most important preventive measure to protect people from coronavirus disease 2019 (COVID-19). Governments worldwide have prioritized their vaccination policy against COVID-19. However, there is a lack of relevant research on Taiwanese attitudes and considerations toward COVID-19 vaccination. This study aimed to investigate the cognition, preventive behaviors, and attitudes toward COVID-19 vaccines that influence people's willingness to get vaccinated in Taiwan.

METHODS

From October 1 to 31, 2021, a computer-assisted telephone interview system was used to randomly select Taiwanese people to investigate their COVID-19 preventive behaviors, knowledge, and willingness to be vaccinated.

RESULTS

We included 2000 participants of whom 96.45% showed vaccination willingness. The overall mean age and knowledge scores were 48.6 years and 5.78, respectively. All of the participants chose to wear masks, and 80% chose to be vaccinated to prevent COVID-19. Compared with the non-willing vaccination participants, those with younger ages, higher incomes, and higher knowledge scores regarding masks and vaccination were more likely to be vaccinated. Furthermore, apprehensions about vaccine side effects and negative news about COVID-19 vaccines were the major reasons for vaccination hesitancy.

CONCLUSION

To improve people's willingness to get vaccinated, the government should strive to deliver correct knowledge and refute inappropriate negative information about COVID-19 vaccination. Moreover, recommendation by physicians was an important factor for older individuals to decide on receiving the COVID-19 vaccine, and policies could be implemented from this aspect.

Metabolic predictors of COVID-19 mortality and severity: a survival analysis

Introduction

The global healthcare burden of COVID-19 pandemic has been unprecedented with a high mortality. Metabolomics, a powerful technique, has been increasingly utilized to study the host response to infections and to understand the progression of multi-system disorders such as COVID-19. Analysis of the host metabolites in response to SARS-CoV-2 infection can provide a snapshot of the endogenous metabolic landscape of the host and its role in shaping the interaction with SARS-CoV-2. Disease severity and consequently the clinical outcomes may be associated with a metabolic imbalance related to amino acids, lipids, and energy-generating pathways. Hence, the host metabolome can help predict potential clinical risks and outcomes.

Methods

In this prospective study, using a targeted metabolomics approach, we studied the metabolic signature in 154 COVID-19 patients (males=138, age range 48-69 yrs) and related it to disease severity and mortality. Blood plasma concentrations of metabolites were quantified through LC-MS using MxP Quant 500 kit, which has a coverage of 630 metabolites from 26 biochemical classes including distinct classes of lipids and small organic molecules. We then employed Kaplan-Meier survival analysis to investigate the correlation between various metabolic markers, disease severity and patient outcomes.

Results

A comparison of survival outcomes between individuals with high levels of various metabolites (amino acids, tryptophan, kynurenine, serotonin, creatine, SDMA, ADMA, 1-MH and carnitine palmitoyltransferase 1 and 2 enzymes) and those with low levels revealed statistically significant differences in survival outcomes. We further used four key metabolic markers (tryptophan, kynurenine, asymmetric dimethylarginine, and 1-Methylhistidine) to develop a COVID-19 mortality risk model through the application of multiple machine-learning methods.

Conclusions

Metabolomics analysis revealed distinct metabolic signatures among different severity groups, reflecting discernible alterations in amino acid levels and perturbations in tryptophan metabolism. Notably, critical patients exhibited higher levels of short chain acylcarnitines, concomitant with higher concentrations of SDMA, ADMA, and 1-MH in severe cases and non-survivors. Conversely, levels of 3-methylhistidine were lower in this context.

Chemotherapy and COVID-19 Vaccination in Patients With Gastrointestinal Cancer

BACKGROUND/AIM

Multiple doses of vaccines against the coronavirus disease (COVID-19) provide patients with cancer the opportunity to continue cancer treatment. This study investigated the safety and efficacy of COVID-19 vaccination in patients with cancer and the optimal timing of vaccination during chemotherapy.

PATIENTS AND METHODS

A total of 131 patients with gastrointestinal (GI) cancer who received two doses of the COVID-19 vaccine were included in this study. This study combined two cohorts: an evaluation cohort of 79 patients receiving chemotherapy and a control cohort of 52 patients under follow-up after radical surgery. None of the patients had any history of COVID-19. Treatment- and vaccine-related adverse events (AEs) were recorded through outpatient interviews and self-reports.

RESULTS

In the evaluation cohort, 62 patients (78.4%) experienced vaccine-related AEs after the first dose, and 62 patients (78.4%) experienced vaccine-related AEs with an increased rate of fever and fatigue after the second dose. In the control cohort, vaccine-related AEs occurred in 28 (53.8%) patients after the first dose and in 37 (71.2%) patients after the second dose, with increased fever and fatigue after the second dose. Of the 79 patients, 49 received chemotherapy before vaccination. Twelve patients (24.5%) changed their treatment schedule: four for safety reasons, four for myelosuppression, and four for convenience. Three patients discontinued the treatment because of disease progression.

CONCLUSION

Systemic chemotherapy in patients with GI cancer does not have a markedly negative effect on COVID-19 vaccination, resulting in manageable vaccine-related AEs, and minimizing the need for treatment schedule changes.

Interpretations of Studies on SARS-CoV-2 Vaccination and Post-acute COVID-19 Sequelae

This article discusses causal interpretations of epidemiologic studies of the effects of vaccination on sequelae after acute severe acute respiratory syndrome coronavirus 2 infection. To date, researchers have tried to answer several different research questions on this topic. While some studies assessed the impact of postinfection vaccination on the presence of or recovery from post-acute coronavirus disease 2019 syndrome, others quantified the association between preinfection vaccination and postacute sequelae conditional on becoming infected. However, the latter analysis does not have a causal interpretation, except under the principal stratification framework-that is, this comparison can only be interpreted as causal for a nondiscernible stratum of the population. As the epidemiology of coronavirus disease 2019 is now nearly entirely dominated by reinfections, including in vaccinated individuals, and possibly caused by different Omicron subvariants, it has become even more important to design studies on the effects of vaccination on postacute sequelae that address precise causal questions and quantify effects corresponding to implementable interventions.

Effect of Corticosteroid on Immunogenicity of SARS-CoV-2 Vaccines in Patients With Solid Cancer

PURPOSE

Corticosteroids are known to diminish immune response ability, which is generally used in routine premedication for chemotherapy. The intersecting of timeframe between the corticosteroid's duration of action and peak COVID-19 vaccine efficacy could impair vaccine immunogenicity. Thus, inquiring about corticosteroids affecting the efficacy of vaccines to promote effective immunity in this population is needed.

METHODS

This was a prospective longitudinal observational cohort study that enrolled patients with solid cancer classified into dexamethasone- and nondexamethasone-receiving groups. All participants were immunized with two doses of ChAdOx1 nCoV-19 or CoronaVac vaccines. This study's purpose was to compare corticosteroid's effect on immunogenicity responses to the SARS-CoV-2 S protein in patients with cancer after two doses of COVID-19 vaccine in the dexamethasone and nondexamethasone group. Secondary outcomes included the postimmunization anti-spike (S) immunoglobin G (IgG) seroconversion rate, the association of corticosteroid dosage, time duration, and immunogenicity level.

RESULTS

Among the 161 enrolled patients with solid cancer, 71 and 90 were in the dexamethasone and nondexamethasone groups, respectively. The median anti-S IgG titer after COVID-19 vaccination in the dexamethasone group was lower than that in the nondexamethasone group with a statistically significant difference (47.22 v 141.09 U/mL, P = .035). The anti-S IgG seroconversion rate was also significantly lower in the dexamethasone group than in the nondexamethasone group (93.83% v 80.95%, P = .023). The lowest median anti-SARS-CoV-2 IgG titer level at 7.89 AU/mL was observed in patients with the highest dose of steroid group (≥37 mg of dexamethasone cumulative dose throughout the course of chemotherapy [per course]) and patients who were injected with COVID-19 vaccines on the same day of receiving dexamethasone, 25.41 AU/mL.

CONCLUSION

Patients with solid cancer vaccinated against COVID-19 disease while receiving dexamethasone had lower immunogenicity responses than those who got vaccines without dexamethasone. The direct association between the immunogenicity level and steroid dosage, as well as length of duration from vaccination to dexamethasone, was observed.

Prior COVID-19 vaccination and reduced risk of cerebrovascular diseases among COVID-19 survivors

The effects of COVID-19 vaccination on short-term and long-term cerebrovascular risks among COVID-19 survivors remained unknown. We conducted a national multi-center retrospective cohort study with 151 597 vaccinated and 151 597 unvaccinated COVID-19 patients using the TriNetX database, from January 1, 2020 to December 31, 2023. Patients baseline characteristics were balanced with propensity score matching (PSM). The outcomes were incident cerebrovascular diseases occurred between 1st and 30th days (short-term) after COVID-19 diagnosis. Nine subgroup analyses were conducted to explore potential effect modifications. We performed six sensitivity analyses, including evaluation of outcomes between 1st to 180th days, accounting for competing risk, and incorporating different variant timeline to test the robustness of our results. Kaplan-Meier curves and Log-Rank tests were performed to evaluate survival difference. Cox proportional hazards regressions were adopted to estimate the PSM-adjusted hazard ratios (HR). The overall short-term cerebrovascular risks were lower in the vaccinated group compared to the unvaccinated group (HR: 0.66, 95% CI: 0.56-0.77), specifically cerebral infarction (HR: 0.62, 95% CI: 0.48-0.79), occlusion and stenosis of precerebral arteries (HR: 0.74, 95% CI: 0.53-0.98), other cerebrovascular diseases (HR: 0.57, 95% CI: 0.42-0.77), and sequelae of cerebrovascular disease (HR: 0.39, 95% CI:0.23-0.68). Similarly, the overall cerebrovascular risks were lower in those vaccinated among most subgroups. The long-term outcomes, though slightly attenuated, were consistent (HR: 0.80, 95% CI: 0.73-0.87). Full 2-dose vaccination was associated with a further reduced risk of cerebrovascular diseases (HR: 0.63, 95% CI: 0.50-0.80) compared to unvaccinated patients. Unvaccinated COVID-19 survivors have significantly higher cerebrovascular risks than their vaccinated counterparts. Thus, clinicians are recommended to monitor this population closely for stroke events during postinfection follow-up.

Comparative safety analysis of mRNA and adenoviral vector COVID-19 vaccines: a nationwide cohort study using an emulated target trial approach

OBJECTIVE

This nationwide cohort study compared the incidence of adverse events of special interest (AESIs) between adenoviral vector-based (ChAdOx1) and mRNA-based (BNT162b2 or mRNA-1273) coronavirus disease 2019 (COVID-19) vaccines.

METHODS

A targeted trial emulation study was conducted using data from the National Health Insurance Service database. Vaccinees aged 18-85 years who had received at least one dose of ChAdOx1 or an mRNA-based vaccine were identified. The 42-day risks of AESIs were calculated.

RESULTS

A total of 1 767 539 ChAdOx1 vaccinees were matched exactly with mRNA vaccinees according to their risk factors. The 42-day risks of adverse events were low (∼0 to 176 events per 100 000 persons in both vaccine groups), and the incidence rates of AESIs were comparable between the two platforms, except for a higher occurrence of acute cardiac injury (incidence rate ratio [IRR], 1.22; 95% CI, 1.10-1.35), myocarditis or pericarditis (IRR, 2.14; 95% CI, 1.14-4.04), and arrhythmia (IRR, 1.46; 95% CI, 1.24-1.71) in mRNA vaccinees. The incidence of Guillain-Barré syndrome (IRR, 0.20; 95% CI, 0.06-0.69), vasovagal syncope (IRR, 0.77; 95% CI, 0.62-0.97), radiculopathy (IRR = 0.59, 95% CI, 0.41-0.84), and aseptic arthritis (IRR, 0.81; 95% CI, 0.70-0.93) was significantly lower in mRNA-based vaccinees compared with ChAdOx1 vaccinees.

DISCUSSION

A remarkable platform-dependent difference was observed in the safety profiles of COVID-19 vaccines, particularly for myocarditis or pericarditis and Guillain-Barré syndrome. However, the overall risk of AESIs was low for both vaccine platforms.

Design of multi-epitope chimeric vaccine against Monkeypox virus and SARS-CoV-2: A vaccinomics perspective

The current era we experience is full with pandemic infectious agents that no longer threatens the major local source but the whole globe. Almost the most emerging infectious agents are severe acute respiratory syndrome coronavirus-2 (SARS CoV-2), followed by monkeypox virus (MPXV). Since no approved antiviral drugs nor licensed active vaccines are yet available, we aimed to utilize immunoinformatics approach to design chimeric vaccine against the two mentioned viruses. This is the first study to deal with design divalent vaccine against SARS-CoV-2 and MPXV. ORF8, E and M proteins from Omicron SARS-CoV-2 and gp182 from MPXV were used as the protein precursor from which multi-epitopes (inducing B-cell, helper T cells, cytotoxic T cells and interferon-ɣ) chimeric vaccine was contrived. The structure of the vaccine construct was predicted, validated, and docked to toll-like receptor-2 (TLR-2). Moreover, its sequence was also used to examine the immune simulation profile and was then inserted into the pET-28a plasmid for in silico cloning. The vaccine construct was probable antigen (0.543) and safe (non-allergen) with strong binding energy to TLR-2 (-1169.8 kcal/mol) and found to have significant immune simulation profile. In conclusion, the designed chimeric vaccine was potent and safe against SARS-CoV-2 and MPXV, which deserves further consideration.

A chimeric adenovirus-vectored vaccine based on Beta spike and Delta RBD confers a broad-spectrum neutralization against Omicron-included SARS-CoV-2 variants

Urgent research into innovative severe acute respiratory coronavirus-2 (SARS-CoV-2) vaccines that may successfully prevent various emerging emerged variants, particularly the Omicron variant and its subvariants, is necessary. Here, we designed a chimeric adenovirus-vectored vaccine named Ad5-Beta/Delta. This vaccine was created by incorporating the receptor-binding domain from the Delta variant, which has the L452R and T478K mutations, into the complete spike protein of the Beta variant. Both intramuscular (IM) and intranasal (IN) vaccination with Ad5-Beta/Deta vaccine induced robust broad-spectrum neutralization against Omicron BA.5-included variants. IN immunization with Ad5-Beta/Delta vaccine exhibited superior mucosal immunity, manifested by higher secretory IgA antibodies and more tissue-resident memory T cells (TRM) in respiratory tract. The combination of IM and IN delivery of the Ad5-Beta/Delta vaccine was capable of synergically eliciting stronger systemic and mucosal immune responses. Furthermore, the Ad5-Beta/Delta vaccination demonstrated more effective boosting implications after two dosages of mRNA or subunit recombinant protein vaccine, indicating its capacity for utilization as a booster shot in the heterologous vaccination. These outcomes quantified Ad5-Beta/Delta vaccine as a favorable vaccine can provide protective immunity versus SARS-CoV-2 pre-Omicron variants of concern and BA.5-included Omicron subvariants.

Mucosal vaccines for viral diseases: Status and prospects

Virus-associated infectious diseases are highly detrimental to human health and animal husbandry. Among all countermeasures against infectious diseases, prophylactic vaccines, which developed through traditional or novel approaches, offer potential benefits. More recently, mucosal vaccines attract attention for their extraordinary characteristics compared to conventional parenteral vaccines, particularly for mucosal-related pathogens. Representatively, coronavirus disease 2019 (COVID-19), a respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), further accelerated the research and development efforts for mucosal vaccines by thoroughly investigating existing strategies or involving novel techniques. While several vaccine candidates achieved positive progresses, thus far, part of the current COVID-19 mucosal vaccines have shown poor performance, which underline the need for next-generation mucosal vaccines and corresponding platforms. In this review, we summarized the typical mucosal vaccines approved for humans or animals and sought to elucidate the underlying mechanisms of these successful cases. In addition, mucosal vaccines against COVID-19 that are in human clinical trials were reviewed in detail since this public health event mobilized all advanced technologies for possible solutions. Finally, the gaps in developing mucosal vaccines, potential solutions and prospects were discussed. Overall, rational application of mucosal vaccines would facilitate the establishing of mucosal immunity and block the transmission of viral diseases.

A COVID-19 perspective of multiple evanescent white dot syndrome (MEWDS)

Multiple evanescent white dot syndrome (MEWDS) is a rare form of posterior uveitis characterized by involvement in the posterior pole and mid-periphery. A viral etiology that provokes an immune-mediated response has been hypothesized to be the inciting factor of the pathology. Recently, there has been an increase in the literature regarding new-onset uveitis and reactivation of previously diagnosed cases of uveitis following COVID-19 vaccinations. The COVID-19 vaccination has been speculated to trigger an immunomodulatory shift in recipients, resulting in an autoimmune event. MEWDS following COVID-19 vaccination was reported in 31 patients. It was most commonly observed following the first dose, affecting 15 patients, and least commonly after the booster dose, in only one patient. MEWDS-like disease following anti-SARS-CoV-2 vaccinations was reported the most in 16 cases after the Pfizer-BioNTech vaccination (BNT162b2 mRNA). Most of these cases had Primary MEWDS without any previous history of a similar event in the past.

A phase 3 randomized controlled trial of a COVID-19 recombinant vaccine S-268019-b versus ChAdOx1 nCoV-19 in Japanese adults

We assessed S-268019-b, a recombinant spike protein vaccine with a squalene-based adjuvant, for superiority in its immunogenicity over ChAdOx1 nCoV-19 vaccine among adults in Japan. In this multicenter, randomized, observer-blinded, phase 3 study, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-naïve participants (aged ≥ 18 years, without prior infection or vaccination against SARS-CoV-2) were randomized (1:1) to receive either S-268019-b or ChAdOx1 nCoV-19 as two intramuscular injections given 28 days apart. Participants who provided consent for a booster administration received S-268019-b at Day 211. The primary endpoint was SARS-CoV-2 neutralizing antibody (NAb) titer on Day 57; the key secondary endpoint was the seroconversion rate for SARS-CoV-2 NAb titer on Day 57. Other endpoints included anti-SARS-CoV-2 S-protein immunoglobulin (Ig)G antibody titer and safety. The demographic and baseline characteristics were generally comparable between S-268019-b (n = 611) and ChAdOx1 nCoV-19 (n = 610) groups. S-268019-b showed superior immunogenicity over ChAdOx1 nCoV-19, based on their geometric mean titers (GMTs) and GMT ratios of SARS-CoV-2 NAb on Day 57 by cytopathic effect assay (GMT [95% confidence interval {CI}] 19.92 [18.68, 21.23] versus 3.63 [3.41, 3.87]; GMT ratio [95% CI] 5.48 [5.01, 6.00], respectively; two-sided p-values < 0.0001). Additionally, NAb measured using a cell viability assay also showed similar results (GMT [95% CI] 183.25 [168.04, 199.84] versus 24.79 [22.77, 27.00]; GMT ratio [95% CI] 7.39 [6.55, 8.35] for S-268019-b versus ChAdOx1 nCoV-19, respectively; p < 0.0001). The GMT of anti-SARS-CoV-2 S-protein IgG antibody was 370.05 for S-268019-b versus 77.92 for ChAdOx1 nCoV-19 on Day 57 (GMT ratio [95% CI] 4.75 [4.34, 5.20]). Notably, immune responses were durable through the end of the study. S-268019-b elicited T-helper 1 skewed T-cell response, comparable to that of ChAdOx1 nCoV-19. After the first dose, the incidence of solicited systemic treatment-related adverse events (TRAEs) was higher in the ChAdOx1 nCoV-19 group, but after the second dose, the incidence was higher in the S-268019-b group. Headache, fatigue, and myalgia were the most commonly reported solicited systemic TRAEs, while pain at the injection site was the most frequently reported solicited local TRAE following both doses in both groups. No serious treatment-related adverse serious TRAEs events were reported in the two groups. S-268019-b was more immunogenic than ChAdOx1 nCoV-19 vaccine and was well tolerated (jRCT2051210151).

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.