Anti-SARS-CoV-2 (COVID-19) vaccination efficacy in patients with severe neuromuscular diseases

INTRODUCTION

Patients with severe neuromuscular disease (sNMD) are considered at high risk of severe COVID-19. Muscle tissue is often replaced by fibroadipose tissue in these diseases whereas the new mRNA-based vaccines are injected intramuscularly. We aimed at evaluating the efficacy of two injections associated with a booster injection of mRNA vaccine in these patients.

METHODS

We performed an observational, prospective, single-centre study to investigate the level of anti-S antibodies (Abs) and their neutralization activity at weeks 6 (W6) and 24 (W24) after two injections of mRNA-1273 vaccine and at weeks 12 (BW12) and 29 (BW29) after a booster injection of BNT162b2 vaccine in patients with sNMD.

RESULTS

Thirty-three patients with sNMD were included. At W6, 30 patients (90.1%) showed a protective serum level of specific anti-S Abs with a strong neutralization capacity. We observed a decline over time: only 12 patients (36.3%) retained anti-S Abs levels considered as protective at W24. The neutralization activity remained above the cut off in 23 (69.7%). The booster vaccination restored robust neutralization activity for all analysed 22 patients (100%) at BW12, which was maintained without any significant drop at BW29 (16). No severe adverse event was reported in this cohort and none of the 33 patients developed symptomatic COVID-19 over one year.

CONCLUSIONS

This study provides evidence that most sNMD patients receiving two injections of COVID-19 mRNA-based vaccines develop a strong humoral response after vaccination. A decline over time was observed but a single booster injection restores a long-term immunity. Moreover, no safety issues were observed.

Safety, reactogenicity, and immunogenicity of Ad26.COV2.S: Results of a phase 1, randomized, double-blind, placebo-controlled COVID-19 vaccine trial in Japan

BACKGROUND

This study evaluated safety, reactogenicity, and immunogenicity of a 2-month homologous booster regimen of Ad26.COV2.S in Japanese adults.

METHODS

In this multicenter, placebo-controlled, Phase 1 trial, adults (Cohort 1, aged 20-55 years, N = 125; Cohort 2, aged ≥ 65 years, N = 125) were randomized 2:2:1 to receive Ad26.COV2.S 5 × 1010 viral particles (vp), Ad26.COV2.S 1 × 1011 vp, or placebo, followed by a homologous booster 56 days later. Safety, reactogenicity, and immunogenicity were assessed.

RESULTS

Two hundred participants received Ad26.COV2.S and 50 received placebo. The most frequent solicited local adverse event (AE) was vaccination-site pain, and the most frequent solicited systemic AEs were fatigue, myalgia, and headache. After primary vaccination, neutralizing and binding antibody levels increased through Day 57 (post-prime) in both cohorts. Fourteen days after boosting (Day 71), neutralizing antibody geometric mean titers (GMTs) had almost reached their peak value in Cohort 1 (5 × 1010 vp: GMT = 1049; 1 × 1011 vp: GMT = 1470) and peaked in Cohort 2 (504; 651); at Day 85, GMTs had declined minimally in Cohort 2. For both cohorts, binding antibody levels peaked at Day 71 with minimal decline at Day 85.

CONCLUSION

A single dose and homologous Ad26.COV2.S booster increased antibody responses with an acceptable safety profile in Japanese adults (ClinicalTrials.gov Identifier: NCT04509947).

Durable antibody responses elicited by 1 dose of Ad26.COV2.S and substantial increase after boosting: 2 randomized clinical trials

BACKGROUND

Ad26.COV2.S is a well-tolerated and effective vaccine against COVID-19. We evaluated durability of anti-SARS-CoV-2 antibodies elicited by single-dose Ad26.COV2.S and the impact of boosting.

METHODS

In randomized, double-blind, placebo-controlled, phase 1/2a and phase 2 trials, participants received single-dose Ad26.COV2.S (5 × 1010 viral particles [vp]) followed by booster doses of 5 × 1010 vp or 1.25 × 1010 vp. Neutralizing antibody levels were determined by a virus neutralization assay (VNA) approximately 8-9 months after dose 1. Binding and neutralizing antibody levels were evaluated by an enzyme-linked immunosorbent assay and pseudotyped VNA 6 months after dose 1 and 7 and 28 days after boosting.

RESULTS

Data were analyzed from phase 1/2a participants enrolled from 22 July-18 December 2020 (Cohort 1a, 18-55 years [y], N = 25; Cohort 2a, 18-55y, N = 17; Cohort 3, ≥65y, N = 22), and phase 2 participants from 14 to 22 September 2020 (18-55y and ≥ 65y, N = 73). Single-dose Ad26.COV2.S elicited stable neutralizing antibodies for at least 8-9 months and stable binding antibodies for at least 6 months, irrespective of age. A 5 × 1010 vp 2-month booster dose increased binding antibodies by 4.9- to 6.2-fold 14 days post-boost versus 28 days after initial immunization. A 6-month booster elicited a steep and robust 9-fold increase in binding antibody levels 7 days post-boost. A 5.0-fold increase in neutralizing antibodies was observed by 28 days post-boost for the Beta variant. A 1.25 × 1010 vp 6-month booster elicited a 3.6-fold increase in binding antibody levels at 7 days post-boost versus pre-boost, with a similar magnitude of post-boost responses in both age groups.

CONCLUSIONS

Single-dose Ad26.COV2.S elicited durable antibody responses for at least 8 months and elicited immune memory. Booster-elicited binding and neutralizing antibody responses were rapid and robust, even with a quarter vaccine dose, and stronger with a longer interval since primary vaccination.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04436276, NCT04535453.

An automated high-throughput enterovirus D68 microneutralization assay platform

Virus neutralization assays, widely used to detect and quantify antibodies induced by virus infection, are considered the gold standard for enterovirus serology testing. Conventional microneutralization assays have been used to assess enterovirus D68 (EV-D68) seroprevalence. While manual or automated 96-well assays are valuable, higher-density assays that increase throughput provide the opportunity to more efficiently screen large, population-based serology collections, as well as to test sample sets against multiple virus strains on the same plate or within the same run. Here, automation was implemented for bulk reagent dispensing, serial dilutions, and luminescence measurement to develop a 384-well enterovirus microneutralization assay that increases overall testing throughput, maintains the reproducibility of the standard 96-well assay, and reduces sample volume usage. EV-D68 strains Fermon, 14-18953, and 18-23087 were used to evaluate the automated 384-well microneutralization assay and compare to the conventional 96-well assay. Sensitivity and specificity were evaluated using pooled human sera and positive and negative control antisera. The Lower Limit of quantitation (LLOQ) was the same as for the 96-well assay and coefficients of variations (CV) of 7.35 %, 5.97 %, and 2.85 % for the three EV-D68 strains respectively, were well below the typical goal of ≤ 20 % CV for accuracy. Z-factor analysis yielded results of 0.694, 0.638, and 0.852, for the three EV-D68 strains respectively, indicating a high level of precision, reliability, and robustness. Intra-assay (7.25 %) and inter-assay (7.12 %) variability were well below 20 % CV. Moreover, the 96-well and 384-well versions of the assay were highly concordant, with a 0.955 correlation coefficient in titers obtained for 50 sera tested. Validation of this automated 384-well microneutralization will support its use in large serology screens assessing the presence of EV-D68 neutralizing antibodies in human populations.

SARS-CoV-2 neutralizing activity of polyphenols in a special green tea extract preparation

BACKGROUND

The COVID-19 pandemic will continue to threaten our health care systems in the next years. In addition to vaccination there is a need for effective tools for prevention and treatment. Products from natural sources, like standardized plant extracts offer a wide range of antiviral effects and possible applications.

PURPOSE

The aim of this study was to investigate, whether a sorbitol/lecithin-based throat spray containing concentrated green tea extract (sGTE) interacts with SARS-CoV-2 viral particles and additionally is capable to block the virus replication.

STUDY DESIGN AND METHODS

The antiviral effect was studied in a VeroE6 cell culture model, including concentration/effect correlations and the biological mechanism of virus blockade, using the Wuhan type of SARS CoV-2 as well as its beta- and delta-mutations. In addition, the qualitative and quantitative tannin profile present on the oral mucosa after spray application has been investigated by LC-MS/MS and HPLC-DAD analyses of (-)-epigallocatechin-3-O-gallate (EGCG) and related catechin derivatives.

RESULTS

The findings of this study demonstrate, that sGTE has strong neutralizing activity on SARS-CoV-2 resulting in an up to 6,3E+04-fold reduction of infectivity independent from the strain. The type of interaction of sGTE with surface proteins seems to be direct and non-specific concerning the viral surface protein structures and resembles the general non-specific activity of polyphenols. By HPLC-DAD analysis, eight catechins were identified in sGTE, with EGCG and (-)-epicatechin-3-O-gallate as the most abundant ones. The total content of catechin derivatives, calculated as catechin, was 76 g/100 g. LC-MS/MS and HPLC-DAD analyses of throat swabs after application of a sGTE spray have shown that the concentrations of green tea tannins in the pharyngeal mucosa are higher than the effective dose found in the in vitro studies with SARS-CoV-2, even 1 h after the last application.

CONCLUSION

The findings of this study suggest that sGTE has strong neutralizing activity on SARS-CoV-2 independent from the strain (Wuhan strain, beta- or delta-variants). sGTE might be relevant for reduction of corresponding viral infections when periodically applied to mouth and throat.

Virtual screening and in vitro validation of natural compound inhibitors against SARS-CoV-2 spike protein

The COVID-19 pandemic caused by the SARS-CoV-2 virus has led to a major public health burden and has resulted in millions of deaths worldwide. As effective treatments are limited, there is a significant requirement for high-throughput, low resource methods for the discovery of novel antivirals. The SARS-CoV-2 spike protein plays a key role in viral entry and has been identified as a therapeutic target. Using the available spike crystal structure, we performed a virtual screen with a library of 527 209 natural compounds against the receptor binding domain of this protein. Top hits from this screen were subjected to a second, more comprehensive molecular docking experiment and filtered for favourable ADMET properties. The in vitro activity of 10 highly ranked compounds was assessed using a virus neutralisation assay designed to facilitate viral entry in a physiologically relevant manner via the plasma membrane route. Subsequently, four compounds ZINC02111387, ZINC02122196, SN00074072 and ZINC04090608 were identified to possess antiviral activity in the µM range. These findings validate the virtual screening method as a tool for identifying novel antivirals and provide a basis for future drug development against SARS-CoV-2.

Replication-competent influenza A viruses expressing a red fluorescent protein

Like most animal viruses, studying influenza A in model systems requires secondary methodologies to identify infected cells. To circumvent this requirement, we describe the generation of replication-competent influenza A red fluorescent viruses. These influenza A viruses encode mCherry fused to the viral non-structural 1 (NS1) protein and display comparable growth kinetics to wild-type viruses in vitro. Infection of cells with influenza A mCherry viruses was neutralized with monoclonal antibodies and inhibited with antivirals to levels similar to wild-type virus. Influenza A mCherry viruses were also able to lethally infect mice, and strikingly, dose- and time-dependent kinetics of viral replication were monitored in whole excised mouse lungs using an in vivo imaging system (IVIS). By eliminating the need for secondary labeling of infected cells, influenza A mCherry viruses provide an ideal tool in the ongoing struggle to better characterize the virus and identify new therapeutics against influenza A viral infections.

Humanized-VH/VHH that inhibit HCV replication by interfering with the virus helicase activity

NS3 helicase is a pivotal enzyme involved in the early and late phases of hepatitis C virus (HCV) replication. The primary sequence and tertiary structure of this virus enzyme differ from human helicase to a certain extent; thus this virus protein has potential as a novel anti-HCV target. In this study, recombinant C-terminal NS3 protein of HCV genotype 3a with endowed helicase activity was produced and used as antigen by selecting VH/V(H)H display phage clones from an established humanized-camel single domain antibody library that bound specifically to HCV helicase. The VH/V(H)H derived from phage transfected Escherichia coli clones were linked molecularly to a cell penetrating peptide, i.e., penetratin (PEN). The cell penetrable VH/V(H)H (transbodies) could reduce the amounts of the HCV RNA released into the cell culture fluid and inside Huh7 cells infected with pJFH1 replicon with a greater effect on the former compared to the latter. Regions and residues of the helicase bound by the transbodies were determined by phage mimotope searching and multiple alignments as well as homology modeling and molecular docking. The epitope of one transbody (PEN-V(H)H9) encompassed residues 588RLKPTLHGPTPLLYRLGA605 of the domain 3 necessary for helicase activity while another transbody (PEN-VH59) interacted with the areas covering the phenylalanine loop and arginine clamp of the domain 2 which are important for the proper folding of the enzyme as well as nucleic acid substrate binding. Although the molecular mechanisms of the prototypic transbodies on NS3 helicase need further investigation, these transbodies have high potential as novel, safe and mutation tolerable anti-HCV agents.

Type-specific seroprevalence of bluetongue in Andhra Pradesh, India, during 2005-2009

Bluetongue (BT) is an infectious, arthropod-borne viral disease of domestic and wild ruminants caused by bluetongue virus (BTV), which is a double-stranded segmented RNA virus. Of the 26 confirmed BTV serotypes, 23 were reported in India based on the detection of antibodies or virus. In order to assess the prevalence of different serotypes in Andhra Pradesh, serum samples which were positive for BTV by group-specific antibody ELISA were subjected to type-specific neutralization of BTV serotypes 1, 2, 9, 10, 21 and 23. Of the 52 samples tested, 50.0, 44.23, 21.15, 26.92, 0, and 15.38 % neutralized BTV serotypes 1, 2, 9, 10, 21 and 23, respectively. However, 32.69 % of the ELISA positive sera could not neutralize any of these serotypes, indicating that there could be other serotype viruses (e.g., BTV-3 and -16) circulating in the State. This method can be used for surveillance of the circulating serotypes as well as for assessing the level of herd immunity, and assist in determining the vaccine strains to be used in multivalent vaccines.