Causal associations between type 1 diabetes and COVID-19 infection and prognosis: a two-sample Mendelian randomization study.

INTRODUCTION: It has been suggested that type 1 diabetes was associated with increased COVID-19 morbidity and mortality. However, their causal relationship is still unclear. Herein, we performed a two-sample Mendelian randomization (MR) to investigate the causal effect of type 1 diabetes on COVID-19 infection and prognosis. RESEARCH DESIGN AND METHODS: The summary statistics of type 1 diabetes were obtained from two published genome-wide association studies of European population, one as a discovery sample including 15 573 cases and 158 408 controls, and the other data as a replication sample consisting of 5913 cases and 8828 controls. We first performed a two-sample MR analysis to evaluate the causal effect of type 1 diabetes on COVID-19 infection and prognosis. Then, reverse MR analysis was conducted to determine whether reverse causality exists. RESULTS: MR analysis results showed that the genetically predicted type 1 diabetes was associated with higher risk of severe COVID-19 (OR=1.073, 95% CI: 1.034 to 1.114, pFDR=1.15×10-3) and COVID-19 death (OR=1.075, 95% CI: 1.033 to 1.119, pFDR=1.15×10-3). Analysis of replication dataset showed similar results, namely a positive association between type 1 diabetes and severe COVID-19 (OR=1.055, 95% CI: 1.029 to 1.081, pFDR=1.59×10-4), and a positively correlated association with COVID-19 death (OR=1.053, 95% CI: 1.026 to 1.081, pFDR=3.50×10-4). No causal association was observed between type 1 diabetes and COVID-19 positive, hospitalized COVID-19, the time to the end of COVID-19 symptoms in the colchicine treatment group and placebo treatment group. Reverse MR analysis showed no reverse causality. CONCLUSIONS: Type 1 diabetes had a causal effect on severe COVID-19 and death after COVID-19 infection. Further mechanistic studies are needed to explore the relationship between type 1 diabetes and COVID-19 infection and prognosis.

RNase2 is a possible trigger of acute-on-chronic inflammation leading to mRNA vaccine-associated cardiac complication.

BACKGROUND: Post-mRNA vaccination-associated cardiac complication is a rare but life-threatening adverse event. Its risk has been well balanced by the benefit of vaccination-induced protection against severe COVID-19. As the rate of severe COVID-19 has consequently declined, future booster vaccination to sustain immunity, especially against infection with new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, may encounter benefit-risk ratios that are less favorable than at the start of the COVID-19 vaccination campaign. Understanding the pathogenesis of rare but severe vaccine-associated adverse events to minimize its risk is thus urgent. METHODS: Here, we report a serendipitous finding of a case of cardiac complication following a third shot of COVID-19 mRNA vaccine. As this case was enrolled in a cohort study, pre-vaccination and pre-symptomatic blood samples were available for genomic and multiplex cytokine analyses. FINDINGS: These analyses revealed the presence of subclinical chronic inflammation, with an elevated expression of RNASE2 at pre-booster baseline as a possible trigger of an acute-on-chronic inflammation that resulted in the cardiac complication. RNASE2 encodes for the ribonuclease RNase2, which cleaves RNA at the 3' side of uridine, which may thus remove the only Toll-like receptor (TLR)-avoidance safety feature of current mRNA vaccines. CONCLUSIONS: These pre-booster and pre-symptomatic gene and cytokine expression data provide unique insights into the possible pathogenesis of vaccine-associated cardiac complication and suggest the incorporation of additional nucleoside modification for an added safety margin. FUNDING: This work was funded by the NMRC Open Fund-Large Collaborative Grant on Integrated Innovations on Infectious Diseases (OFLCG19May-0034).

Early induction of anti-Spike binding antibodies and T cells confer protection against COVID-19 in children during an Omicron wave (preprint)

For improved safety, children are vaccinated with a lower dose and extended interval for mRNA COVID-19 vaccines; however, whether there is protection before dose 2 is unknown. We recruited 113 children receiving BNT162b2 primary vaccination during an Omicron wave. After dose 1, 96% had detectable anti-Spike(S) IgG and 100% had S-reactive T cells; those with both had a lower risk of symptomatic infection compared to those with undetectable anti-S IgG [RR 0.19 (95% CI; 0.06, 0.59)]. This suggests that dosing can be extended without risk of insufficient early protection.

A phase I/II randomized, double-blinded, placebo-controlled trial of a self-amplifying Covid-19 mRNA vaccine.

Coronavirus disease-19 (Covid-19) pandemic have demonstrated the importantance of vaccines in disease prevention. Self-amplifying mRNA vaccines could be another option for disease prevention if demonstrated to be safe and immunogenic. Phase 1 of this randomized, double-blinded, placebo-controlled trial (N = 42) assessed the safety, tolerability, and immunogenicity in healthy young and older adults of ascending levels of one-dose ARCT-021, a self-amplifying mRNA vaccine against Covid-19. Phase 2 (N = 64) tested two-doses of ARCT-021 given 28 days apart. During phase 1, ARCT-021 was well tolerated up to one 7.5 µg dose and two 5.0 µg doses. Local solicited AEs, namely injection-site pain and tenderness were more common in ARCT-021vaccinated, while systemic solicited AEs, mainly fatigue, headache and myalgia were reported in 62.8% and 46.4% of ARCT-021 and placebo recipients, respectively. Seroconversion rate for anti-S IgG was 100% in all cohorts, except for the 1 µg one-dose in younger adults and the 7.5 µg one-dose in older adults. Anti-S IgG and neutralizing antibody titers showed a general increase with increasing dose, and overlapped with titers in Covid-19 convalescent patients. T-cell responses were also observed in response to stimulation with S-protein peptides. Taken collectively, ARCT-021 is immunogenic and has favorable safety profile for further development.

Immune gene expression analysis indicates the potential of a self-amplifying Covid-19 mRNA vaccine.

Remarkable potency has been demonstrated for mRNA vaccines in reducing the global burden of the ongoing COVID-19 pandemic. An alternative form of the mRNA vaccine is the self-amplifying mRNA (sa-mRNA) vaccine, which encodes an alphavirus replicase that self-amplifies the full-length mRNA and SARS-CoV-2 spike (S) transgene. However, early-phase clinical trials of sa-mRNA COVID-19 vaccine candidates have questioned the potential of this platform to develop potent vaccines. We examined the immune gene response to a candidate sa-mRNA vaccine against COVID-19, ARCT-021, and compared our findings to the host response to other forms of vaccines. In blood samples from healthy volunteers that participated in a phase I/II clinical trial, greater induction of transcripts involved in Toll-like receptor (TLR) signalling, antigen presentation and complement activation at 1 day post-vaccination was associated with higher anti-S antibody titers. Conversely, transcripts involved in T-cell maturation at day 7 post-vaccination informed the magnitude of eventual S-specific T-cell responses. The transcriptomic signature for ARCT-021 vaccination strongly correlated with live viral vector vaccines, adjuvanted vaccines and BNT162b2 1 day post-vaccination. Moreover, the ARCT-021 signature correlated with day 7 YF17D live-attenuated vaccine transcriptomic responses. Altogether, our findings show that sa-mRNA vaccination induces innate immune responses that are associated with the development of adaptive immunity from other forms of vaccines, supporting further development of this vaccine platform for clinical application.

Adverse effects following anti-COVID-19 vaccination with mRNA-based BNT162b2 are alleviated by altering the route of administration and correlate with baseline enrichment of T and NK cell genes.

Ensuring high vaccination and even booster vaccination coverage is critical in preventing severe Coronavirus Disease 2019 (COVID-19). Among the various COVID-19 vaccines currently in use, the mRNA vaccines have shown remarkable effectiveness. However, systemic adverse events (AEs), such as postvaccination fatigue, are prevalent following mRNA vaccination, and the underpinnings of which are not understood. Herein, we found that higher baseline expression of genes related to T and NK cell exhaustion and suppression were positively correlated with the development of moderately severe fatigue after Pfizer-BioNTech BNT162b2 vaccination; increased expression of genes associated with T and NK cell exhaustion and suppression reacted to vaccination were associated with greater levels of innate immune activation at 1 day postvaccination. We further found, in a mouse model, that altering the route of vaccination from intramuscular (i.m.) to subcutaneous (s.c.) could lessen the pro-inflammatory response and correspondingly the extent of systemic AEs; the humoral immune response to BNT162b2 vaccination was not compromised. Instead, it is possible that the s.c. route could improve cytotoxic CD8 T-cell responses to BNT162b2 vaccination. Our findings thus provide a glimpse of the molecular basis of postvaccination fatigue from mRNA vaccination and suggest a readily translatable solution to minimize systemic AEs.

Reusing Face Covering Masks: Probing the Impact of Heat Treatment

The COVID-19 pandemic resulted in imminent shortages of personal protective equipment such as face masks. To address the shortage, new sterilization or decontamination procedures for masks are quickly being developed and employed. Dry heat and steam sterilization processes are easily scalable and allow treatment of large sample sizes, thus potentially presenting fast and efficient decontamination routes, which could significantly ease the rapidly increasing need for protective masks globally during a pandemic like COVID-19. In this study, a suite of structural and chemical characterization techniques, including scanning electron microscopy (SEM), contact angle, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman were utilized to probe the heat treatment impact on commercially available 3M 8210 N95 Particulate Respirator and VWR Advanced Protection surgical mask. Unique to this study is the use of the synchrotron-based In situ and Operando Soft X-ray Spectroscopy (IOS) beamline (23-ID-2) housed at the National Synchrotron Light Source II at Brookhaven National Laboratory for near-edge X-ray absorption spectroscopy (NEXAFS). The impact of heat recycling procedures on the structural integrity and surface chemistry of the N95 and surgical masks was assessed by a suite of structural and chemical characterization techniques.

Immune gene expression analysis indicates the potential of a self-amplifying Covid-19 mRNA vaccine (preprint)

Remarkable potency has been demonstrated for mRNA vaccines in reducing the global burden of the ongoing COVID-19 pandemic. This vaccine platform has been extended to encode an alphavirus replicase that self-amplifies the full length mRNA and SARS-CoV-2 spike (S) transgene (self-amplifying mRNA or sa mRNA). However, early phase clinical trials of sa-mRNA COVID-19 vaccine candidates have questioned the potential of this platform to develop potent vaccines. We examined the immune gene response to a candidate sa-mRNA vaccine against COVID-19, and compared our findings to the host response to other forms of vaccines. In blood samples from healthy volunteers that participated in a phase I/II clinical trial, greater induction of transcripts involved in Toll-like receptor (TLR) signalling, antigen presentation and complement activation at 1 day post-vaccination was associated with higher anti-S antibody titers. Conversely, transcripts involved in T-cell maturation at day 7 post-vaccination informed the magnitude of eventual anti-S T-cell responses. The transcriptomic signature for ARCT-021 vaccination strongly correlated with live viral vector vaccines, adjuvanted vaccines and BNT162b2. Correlation with live attenuated vaccines was weaker. Our findings suggest the potential for sa-mRNA to be further developed to be among the most potent forms of vaccines in our arsenal to prevent infectious diseases.

Dry heat sterilization as a method to recycle N95 respirator masks: The importance of fit.

In times of crisis, including the current COVID-19 pandemic, the supply chain of filtering facepiece respirators, such as N95 respirators, are disrupted. To combat shortages of N95 respirators, many institutions were forced to decontaminate and reuse respirators. While several reports have evaluated the impact on filtration as a measurement of preservation of respirator function after decontamination, the equally important fact of maintaining proper fit to the users' face has been understudied. In the current study, we demonstrate the complete inactivation of SARS-CoV-2 and preservation of fit test performance of N95 respirators following treatment with dry heat. We apply scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) measurements, Raman spectroscopy, and contact angle measurements to analyze filter material changes as a consequence of different decontamination treatments. We further compared the integrity of the respirator after autoclaving versus dry heat treatment via quantitative fit testing and found that autoclaving, but not dry heat, causes the fit of the respirator onto the users face to fail, thereby rendering the decontaminated respirator unusable. Our findings highlight the importance to account for both efficacy of disinfection and mask fit when reprocessing respirators to for clinical redeployment.

Characterization of Materials Used as Face Coverings for Respiratory Protection.

Use of masks is a primary tool to prevent the spread of the novel COVID-19 virus resulting from unintentional close contact with infected individuals. However, detailed characterization of the chemical properties and physical structure of common mask materials is lacking in the current literature. In this study, a series of commercial masks and potential mask materials, including 3M Particulate Respirator 8210 N95, a material provided by Oak Ridge National Laboratory Carbon Fiber Technology Facility (ORNL/CFTF), and a Filti Face Mask Material, were characterized by a suite of techniques, including scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Wetting properties of the mask materials were quantified by measurements of contact angle with a saliva substitute. Mask pass-through experiments were performed using a dispersed metal oxide nanoparticle suspension to model the SARS-CoV-2 virus, with quantification via spatially resolved X-ray fluorescence mapping. Notably, all mask materials tested provided a strong barrier against respiratory droplet breakthrough. The comparisons and characterizations provided in this study provide useful information when evaluating mask materials for respiratory protection.

A single dose of self-transcribing and replicating RNA-based SARS-CoV-2 vaccine produces protective adaptive immunity in mice.

A self-transcribing and replicating RNA (STARR)-based vaccine (LUNAR-COV19) has been developed to prevent SARS-CoV-2 infection. The vaccine encodes an alphavirus-based replicon and the SARS-CoV-2 full-length spike glycoprotein. Translation of the replicon produces a replicase complex that amplifies and prolongs SARS-CoV-2 spike glycoprotein expression. A single prime vaccination in mice led to robust antibody responses, with neutralizing antibody titers increasing up to day 60. Activation of cell-mediated immunity produced a strong viral antigen-specific CD8+ T lymphocyte response. Assaying for intracellular cytokine staining for interferon (IFN)γ and interleukin-4 (IL-4)-positive CD4+ T helper (Th) lymphocytes as well as anti-spike glycoprotein immunoglobulin G (IgG)2a/IgG1 ratios supported a strong Th1-dominant immune response. Finally, single LUNAR-COV19 vaccination at both 2 µg and 10 µg doses completely protected human ACE2 transgenic mice from both mortality and even measurable infection following wild-type SARS-CoV-2 challenge. Our findings collectively suggest the potential of LUNAR-COV19 as a single-dose vaccine.

A phase 1/2 randomized, double-blinded, placebo controlled ascending dose trial to assess the safety, tolerability and immunogenicity of ARCT-021 in healthy adults (preprint)

BackgroundThe pandemic of coronavirus disease-19 (Covid-19) continues to afflict the lives and livelihoods of many as global demand for vaccine supply remains unmet. MethodsPhase 1 of this trial (N=42) assessed the safety, tolerability and immunogenicity of ascending levels of one-dose ARCT-021, a self-amplifying mRNA vaccine against Covid-19. Phase 2 (N=64) tested two-doses of ARCT-021 given 28 days apart. Both young and older adults were enrolled. The primary safety outcomes were local and systemic solicited adverse events (AEs) reported immediately and up to 7 days post-inoculation and unsolicited events reported up to 56 days after inoculation. Secondary and exploratory outcomes were antibody and T cell responses to vaccination, respectively. ResultsARCT-021 was well tolerated up to one 7.5 g dose and two 5.0 g doses. Local solicited AEs, namely injection-site pain and tenderness, as well as systemic solicited AEs, such as fatigue, headache and myalgia, were more common in ARCT-021 than placebo recipients, and in younger than older adults. Seroconversion rate for anti-S IgG was 100% in all cohorts except for the 1 g one-dose in younger adults and the 7.5 g one-dose in older adults, which were each 80%. Neutralizing antibody titers increased with increasing dose although the responses following 5.0 g and 7.5 g ARCT-021 were similar. Anti-S IgG titers overlapped with those in Covid-19 convalescent plasma. ARCT-021 also elicited T-cell responses against the S glycoprotein. ConclusionTaken collectively, the favorable safety and immunogenicity profiles support further clinical development of ARCT-021.

Early T cell and binding antibody responses are associated with COVID-19 RNA vaccine efficacy onset.

BACKGROUND: RNA vaccines against coronavirus disease 2019 (COVID-19) have demonstrated ∼95% efficacy in phase III clinical trials. Although complete vaccination consisted of 2 doses, the onset of protection for both licensed RNA vaccines was observed as early as 12 days after a single dose. The adaptive immune response that coincides with this onset of protection could represent the necessary elements of immunity against COVID-19. METHODS: Serological and T cell analysis was performed in a cohort of 20 healthcare workers after receiving the first dose of the Pfizer/BioNTech BNT162b2 vaccine. The primary endpoint was the adaptive immune responses detectable at days 7 and 10 after dosing. FINDINGS: Spike-specific T cells and binding antibodies were detectable 10 days after the first dose of the vaccine, in contrast to receptor-blocking and severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) neutralizing antibodies, which were mostly undetectable at this early time point. CONCLUSIONS: Our findings suggest that early T cell and binding antibody responses, rather than either receptor-blocking or virus neutralizing activity, induced early protection against COVID-19. FUNDING: The study was funded by a generous donation from The Hour Glass to support COVID-19 research.

Early T Cell and Binding Antibody Responses are Associated with COVID-19 RNA Vaccine Efficacy Onset (preprint)

RNA vaccines against Covid-19 have demonstrated ~95% efficacy in Phase III clinical trials. Although complete vaccination consisted of two-doses, the onset of protection for both licensed RNA vaccines was observed as early as 12 days after a single dose. The adaptive immune response that coincides with this onset of protection could represent the necessary elements of immunity against Covid-19. Herein, we tracked the early adaptive immune responses after Covid-19 RNA vaccination, in a cohort of 20 healthcare workers. Our findings suggest that early T cell and binding antibody responses, rather than either receptor-blocking or virus neutralizing activity, induced early protection against Covid-19.Funding: This study was partially funded through a generousdonation from The Hourglass to support Covid-19 research in ViREMiCS. SK receives salary support from the Transition Award, RdA receives funding from the Open Research Fund Young Investigator Award, JGL and EEO receive salary support from the Clinician Scientist Award, and AB receives salary support from the Singapore Translational Research Award, all administered by the National Medical Research Council of Singapore.Conflict of Interest: Duke-NUS Medical School is in partnership with Arcturus Therapeutics to develop a self-replicating RNA vaccine against Covid-19, with EEO as the principal investigator. No monetary or personal benefits are derived from this partnership.Ethical Approval: This study was approved by the SingHealth Centralized Institutional Review Board (CIRB/F2021/2014). Healthcare workers (HCWs) from the Singapore Health Services institutions whowere eligible for Covid-19 vaccination were invited to participate in this study, and written informed consent was obtained.

Successful treatment of a critically ill patient with acute respiratory distress syndrome from COVID-19 using mechanical ventilation strategy with low levels of positive end-expiratory pressure: A CARE-compliant case report.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) secondary to COVID-19 is different from the ARDS caused by other infections. Conventional mechanical ventilation strategies using high levels of PEEP may not be beneficial and can even be harmful to patient with ARDS from COVID-19. So the ventilation strategies should be adjusted in order to improve the pulmonary ventilation function and oxygenation status, and outcomes of the patient. PATIENT CONCERNS: Herein, we present a 76-year-old male patient with ARDS secondary to COVID-19. We describe our experience with mechanical ventilation strategy and the changes in respiratory mechanics in the patient during treatment. DIAGNOSIS: The patient had tested positive for coronavirus (COVID-19) in nucleic acid test. Chest CT showed multiple ground glass shadows in both lungs. INTERVENTIONS: The patient received mechanical ventilation with low tidal volume and low PEEP. OUTCOMES: After treatment, the patients condition, as well as oxygenation status was improved, and he tested negative for the coronavirus several times. CONCLUSION: This case demonstrated that the low tidal volume with low levels of PEEP ventilation strategy may be more suitable for ARDS from COVID-19.

Asian-Pacific perspective on the psychological well-being of healthcare workers during the evolution of the COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has led to significant strain on front-line healthcare workers. AIMS: In this multicentre study, we compared the psychological outcomes during the COVID-19 pandemic in various countries in the Asia-Pacific region and identified factors associated with adverse psychological outcomes. METHOD: From 29 April to 4 June 2020, the study recruited healthcare workers from major healthcare institutions in five countries in the Asia-Pacific region. A self-administrated survey that collected information on prior medical conditions, presence of symptoms, and scores on the Depression Anxiety Stress Scales and the Impact of Events Scale-Revised were used. The prevalence of depression, anxiety, stress and post-traumatic stress disorder (PTSD) relating to COVID-19 was compared, and multivariable logistic regression identified independent factors associated with adverse psychological outcomes within each country. RESULTS: A total of 1146 participants from India, Indonesia, Singapore, Malaysia and Vietnam were studied. Despite having the lowest volume of cases, Vietnam displayed the highest prevalence of PTSD. In contrast, Singapore reported the highest case volume, but had a lower prevalence of depression and anxiety. In the multivariable analysis, we found that non-medically trained personnel, the presence of physical symptoms and presence of prior medical conditions were independent predictors across the participating countries. CONCLUSIONS: This study highlights that the varied prevalence of psychological adversity among healthcare workers is independent of the burden of COVID-19 cases within each country. Early psychological interventions may be beneficial for the vulnerable groups of healthcare workers with presence of physical symptoms, prior medical conditions and those who are not medically trained.

The discovery of gene mutations making SARS-CoV-2 well adapted for humans: host-genome similarity analysis of 2594 genomes from China, the USA and Europe (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a positive-sense single-stranded virus approximately 30 kb in length, causes the ongoing novel coronavirus disease-2019 (COVID-19). Studies confirmed significant genome differences between SARS-CoV-2 and SARS-CoV, suggesting that the distinctions in pathogenicity might be related to genomic diversity. However, the relationship between genomic differences and SARS-CoV-2 fitness has not been fully explained, especially for open reading frame (ORF)-encoded accessory proteins. RNA viruses have a high mutation rate, but how SARS-CoV-2 mutations accelerate adaptation is not clear. This study shows that the host-genome similarity (HGS) of SARS-CoV-2 is significantly higher than that of SARS-CoV, especially in the ORF6 and ORF8 genes encoding proteins antagonizing innate immunity in vivo . A power law relationship was discovered between the HGS of ORF3b, ORF6, and N and the expression of interferon (IFN)-sensitive response element (ISRE)-containing promoters. This finding implies that high HGS of SARS-CoV-2 genome may further inhibit IFN I synthesis and cause delayed host innate immunity. An ORF1ab mutation, 10818G>T, which occurred in virus populations with high HGS but rarely in low-HGS populations, was identified in 2594 genomes with geolocations of China, the USA and Europe. The 10818G>T caused the amino acid mutation M37F in the transmembrane protein nsp6. The results suggest that the ORF6 and ORF8 genes and the mutation M37F may play important roles in causing COVID-19. The findings demonstrate that HGS analysis is a promising way to identify important genes and mutations in adaptive strains, which may help in searching potential targets for pharmaceutical agents.

A Single Dose of Self-Transcribing and Replicating RNA Based SARS-CoV-2 Vaccine Produces Protective Adaptive Immunity In Mice (preprint)

A self-transcribing and replicating RNA (STARR) based vaccine (LUNAR-COV19) has been developed to prevent SARS-CoV-2 infection. The vaccine encodes an alphavirus-based replicon and the SARS-CoV-2 full length spike glycoprotein. Translation of the replicon produces a replicase complex that amplifies and prolong SARS-CoV-2 spike glycoprotein expression. A single prime vaccination in mice led to robust antibody responses, with neutralizing antibody titers increasing up to day 60. Activation of cell mediated immunity produced a strong viral antigen specific CD8+ T lymphocyte response. Assaying for intracellular cytokine staining for IFN-gamma; and IL-4 positive CD4+ T helper lymphocytes as well as anti-spike glycoprotein IgG2a/IgG1 ratios supported a strong Th1 dominant immune response. Finally, single LUNAR-COV19 vaccination at both 2 microgram and 10 microgram doses completely protected human ACE2 transgenic mice from both mortality and even measurable infection following wild-type SARS-CoV-2 challenge. Our findings collectively suggest the potential of Lunar-COV19 as a single dose vaccine.