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Possible vaccines/treatment(s) for Coronavirus

Fresh phase 1/2 trial results for Valneva's whole virus, inactivated, adjuvanted vaccine VLA2001.

Preliminary data (n=30) indicate that a 3-dose series of VLA2001 (two doses a month apart followed by a third booster dose 6-7 months later) demonstrated neutralisation of delta/B.1.617.2 (100% of samples) and omicron/B.1.1.529 (87% of samples). Fold reduction relative to ancestral virus was 2.7-fold for delta and 16.7-fold for omicron. No analysis of T cell activity provided.

Valneva are expecting MHRA to be in a position to be able to grant regulatory approval before the end of this quarter.
Does their vaccine have advantages over other ones particularly? I haven't heard much about it.
 
One way would be to develop a vaccine which detects more core attributes of the virus that are less likely to mutate successfully. Which I think is already being done.
It's just that according to TWIV no vaccine has ever achieved that.
And would it be a good thing to have an immune system poised ready to pounce ?
It might be OK as a temporary measure as with "boosters" during a pandemic, but long-term ?

I imagine something similar must be happening with all those viruses up our noses or wherever that never progress to symptomatic disease ...

When I worked in the petri dish and would always get one or sometimes two flu-lites per year, I quite often felt as if I was sickening for something that never materialised ...

My threshold for going in to work was whether I could face cycling the 4 miles and it was all or nothing - I was never likely to be a spreader - unless there was a lot of asymptomatic spread going on...(no sneezing, no runny nose)
 
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Does their vaccine have advantages over other ones particularly? I haven't heard much about it.
Inactivated whole virus has the potential to provide more (all) epitopes, rather than just those in spike, and thus a wider range of epitopes that are more likely to be preserved over variant types (until preserved epitopes are all identified and then specifically engineered for in other platforms). It's also significantly less reactogenic and has been shown to be better tolerated. Separately, given it is a long established traditional vaccine platform, those reluctant to take up more recent technologies, eg mRNA, VLP, DNA or viral vector, might be more inclined to choose it.
 
It's just that according to TWIV no vaccine has ever achieved that.
And would it be a good thing to have an immune system poised ready to pounce ?
It might be OK as a temporary measure as with "boosters" during a pandemic, but long-term ?

I imagine something similar must be happening with all those viruses up our noses or wherever that never progress to symptomatic disease ...

When I worked in the petri dish and would always get one or sometimes two flu-lites per year, I quite often felt as if I was sickening for something that never materialised ...

My threshold for going in to work was whether I could face cycling the 4 miles and it was all or nothing - I was never likely to be a spreader - unless there was a lot of asymptomatic spread going on...(no sneezing, no runny nose)
you are the asymptomatic carrier and I want a hobnob
 
Inactivated whole virus has the potential to provide more (all) epitopes, rather than just those in spike, and thus a wider range of epitopes that are more likely to be preserved over variant types (until preserved epitopes are all identified and then specifically engineered for in other platforms). It's also significantly less reactogenic and has been shown to be better tolerated. Separately, given it is a long established traditional vaccine platform, those reluctant to take up more recent technologies, eg mRNA, VLP, DNA or viral vector, might be more inclined to choose it.
so closer to what bill gates aim for in that gentlegreen post?
 
or ultra-slow-release ?
As per the Crotty study? Can't quite envisage a mechanism for doing that intranasally, though perhaps possible via some sort of slow-release skin patch (maybe MNP) proximal to the upper neck lymph nodes? (It's probably only practical intramuscularly or sub/trans-dermally). Can see various potential issues with that though, both in terms of delivery route (see below) and enthusiasm for uptake.


How would they achieve that ?

So I meant to highlight the following studies concerning intranasal vaccination and IgA a few weeks ago; they are worth noting and relevant to the question you pose.

Regarding vaccines for sterilising immunity, which will need to target the mucosal membranes in the respiratory tract, the route of administration matters (this has been seen before).

First, (Mt Sinai, NYC) an investigation of mucosal antibody response in vaccinees.
Mucosal immune responses are critical to prevent respiratory infections.
A key characteristic of mucosal IgA antibodies is that they are mostly present in the form of multimers (eg dimers). Multimeric IgA antibodies display higher anti-viral activity than monomeric IgA antibodies (the main form of systemic IgA, such as are found in sera and are induced by intramuscular vaccination).
[Mucosal IgA antibodies] are known to provide immediate immunity by eliminating respiratory pathogens before they pass through the mucosal barrier.

The researchers analysed sera and saliva from individuals (n=30, 7M/23F, age range 21-65) with and without COVID-19 at multiple timepoints before and after SARS-CoV-2 mRNA vaccination (a mix of BNT162b2 and mRNA-1273). They observed that vaccination induced only a weak mucosal IgA response in seronaive vaccinees, whilst convalescent vaccinees exhibited a strong mucosal IgA response.
Comparison of anti-SARS-CoV-2 spike mucosal IgA (SIgA) titres in saliva between samples collected during the three different timepoints: pre, 1-100 days post vaccination (DPV), over 100 DPV.
The precise mechanism for the heterogeneity observed is yet to be determined (there are hypotheses that prior infection leads to better IgA homing to the respiratory tract; the immune system does indeed have 'memory'). Intranasal vaccination strategies that can successfully induce mucosal IgA "should be sought for control of the pandemic".
DOI: 10.1101/2021.12.06.21267352.

Then, (Yale/Mt Sinai, NYC) an interesting animal study, here specific to influenza but of relevance to SARS-CoV-2 as well, that illustrates some key advantages of intranasal vaccination over intramuscular (systemic) vaccination in respect of respiratory pathogens.

In an animal model they demonstrated that intranasal (but not systemic) immunisation (here with both protein-based and RNA-based vaccines) induced local IgA secretion in the mucous membranes of the respiratory tract, promoting a wide range of cells expressing such (tissue-resident memory B cells, plasmablasts, and plasma cells), leading to the establishment of IgA-secreting cells in the lung (not seen when the same vaccine was delivered intramuscularly or intraperitoneally). Finally, local IgA secretion was observed to provide superior protection to circulating antibodies alone when experiencing a secondary challenge, whether that be the same strain of flu (that the vaccine was designed to target) or another strain.
Local immunisation induces IgA-producing tissue-resident cells (i.n. = intranasally, i.m. = intramuscularly, i.p. = intraperitoneally). Local vaccination with adjuvanted rNA induces IgA secretion in the lung (i.n. = intranasally, i.m. = intramuscularly, i.p. = intraperitoneally).
In summary, our data demonstrate that IgA-producing cells form in the lung after intranasal immunization and contribute to protection against challenge with homologous and heterologous influenza virus infection. Insights gained from our current study may be useful in designing new vaccines against other respiratory virus infections.
DOI: 10.1126/sciimmunol.abj5129.

See also earlier post #1418.

Note: it is worth mentioning that oral vaccination also has the potential to induce a significant mucosal IgA response. I count at least three oral and five intranasal COVID-19 vaccine candidates under evaluation.

TL;DR:
Intranasal (and perhaps oral) vaccines may promote an immune response capable of significantly reducing infection and thus transmission.
 
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woot :cool:

Published: 13 December 2021

SARS-CoV-2 ferritin nanoparticle vaccine induces robust innate immune activity driving polyfunctional spike-specific T cell responses


We have recently developed a SARS-CoV-2 sub-unit vaccine based on a ferritin nanoparticle platform18 that displays a pre-fusion stabilized spike on its surface22,23. The spike protein was modified to generate a stable spike trimer formation on the ferritin molecule23,24. The stabilized prefusion-spike protein of the Wuhan-Hu-1 strain of SARS-CoV-2 was genetically linked to form a ferritin-fusion recombinant protein, which naturally forms a Spike Ferritin nanoparticle (SpFN). Ferritin is a naturally occurring, ubiquitous, iron-carrying protein that self-oligomerizes into a 24-unit spherical particle and is currently being evaluated as a vaccine platform for influenza in two phase 1 clinical trials (NCT03186781, NCT03814720) with two further trials in the recruitment phase for Epstein-Barr virus (NCT04645147) and Influenza H10 (NCT04579250).
 
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(Spallanzani/Gamaleya) A small study, funded by the Russian Direct Investment Fund, investigating neutralisation (only, no T cell analysis) of Sputnik V versus omicron/BA.1 after the standard two-dose primary series (21 day dosing interval, no third-dose booster).

They measured a decrease in neutralising antibody (live virus assay) to the omicron variant at 8.1-fold for Sputnik V and 21.4-fold for a group of BNT162b2 vaccinees. Analysis showed that 74.2% of Sputnik V and 56.9% of BNT162b2-vaccinated sera had detectable neutralising antibodies to omicron.
Sputnik V and BNT162b2 neutralising antibody titres at 3 months after vaccination with primary series.

Gamaleya claim that Sputnik V demonstrates 2.6 times levels of neutralising antibodies to omicron compared to BNT162b2 at 3 months after the second dose of each (an even greater factor is suggested at 6 months post second dose though Sputnik V sera are confusingly declared as being sampled variously at "months 3-6", which would fundamentally undermine any comparison at that time point). It is however not clear from the preprint whether the assays are directly comparable (eg performed in the same lab under identical conditions with identical stock materials sourced from the same batch). Interpreting neutralisation assay performance between different vaccines is difficult as standardisation can be tricky.

Gamaleya suggest that the apparent superior performance of Sputnik V is down to (i) the use of non-stabilised spike leading to a wider range of antibodies targeting epitopes outside of the heavily mutated RBD, (ii) heterologous regimen and (iii) adenoviral vector delivery better mimicking natural infection (extended half-life of antigen). These points have been suggested as perhaps offering potential advantages in previous studies from other research groups.

Note that the study declares several limitations: small sample numbers, lack of age and comorbidity dependent neutralising antibody response, limited accuracy on samples under the limit of detection and heterogeneity in convalescent vaccinee arm.
DOI: 10.1101/2022.01.15.22269335.

 
Gamaleya suggest that the apparent superior performance of Sputnik V is down to (i) the use of non-stabilised spike leading to a wider range of antibodies targeting epitopes outside of the heavily mutated RBD, (ii) heterologous regimen and (iii) adenoviral vector delivery better mimicking natural infection (extended half-life of antigen). These points have been suggested as perhaps offering potential advantages in previous studies from other research groups.
Pre-fusion issue presumably true of Astra Zeneca too ?
Did they lose out on the heterologous thing ?
 
China's Walvax Biotechnology mRNA vaccine, ARCoV, embarks on a 28k participant trial. ARCoV expresses SARS-CoV-2 RBD only and not the full spike (as seen in all currently approved mRNA vaccines). China has yet to approve a locally produced mRNA vaccine and has not yet imported any other mRNA vaccine.
 
Novavax NVX-CoV2373 ('Nuvaxovid') approved in the UK.
 
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(NIH/Moderna/others) Results from an animal model study into the immunogenicity of an omicron-specific booster version of the Moderna mRNA vaccine.

These suggest that at best there is possibly little advantage in an omicron-specific booster and it might even be somewhat inferior to a booster dose of original, WT based, vaccine (mRNA-1273).
An Omicron boost may not provide greater immunity or protection compared to a boost with the current mRNA-1273 vaccine.
DOI: 10.1101/2022.02.03.479037.
 
Afrigen synthesise mRNA-1273 from public data. The vaccine candidate would be the first to be made based on a widely used vaccine without the assistance and approval of the developer. It is also the first mRNA vaccine designed, developed and produced at lab scale on the African continent.
 
Results of the Novavax NVX-CoV2373 ('Nuvaxovid') phase 3 clinical trial (PREVENT-19) extension in 12-17 years olds (2,247 individuals in the US, primary two-dose series).

Efficacy (defined as PCR confirmed infection at least 7 days after the second dose) to delta (during the period of the trial when it was identified in 100% of all positive cases) was found to be 82.0% (95%CI: 32.4-95.2). Overall efficacy to all COVID-19 was observed to be 79.5% (95%CI: 46.8-92.1).

Immunologically, IgG responses against spike proteins of several variants (including alpha, beta, delta, gamma, mu and omicron) were 2-3 times higher than those observed in adults, with 100% seroconversion. All endpoints were met with non-inferior immunoresponses compared to young adults (18-26 years old) from earlier study work.

Safety and reactogenicity were found to be good with no significant levels of serious and severe adverse reactions compared to placebo arms; local and systemic reactogenicity was generally lower than or similar to adults.
 
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(NIH/Moderna/others) Results from an animal model study into the immunogenicity of an omicron-specific booster version of the Moderna mRNA vaccine.

These suggest that at best there is possibly little advantage in an omicron-specific booster and it might even be somewhat inferior to a booster dose of original, WT based, vaccine (mRNA-1273).

DOI: 10.1101/2022.02.03.479037.
(Moderna) An additional animal model study which reaches a similar conclusion - namely no strong case for rolling out a redesigned booster:
In mice, boosting with mRNA-1273 (original) or mRNA-1273.529 (omicron-specific) enhances protection against B.1.1.529 infection with limited differences in efficacy measured.
DOI: 10.1101/2022.02.07.479419.
 
Notably the first time the FDA has asked a vaccine manufacturer to apply for approval rather than the other way around.
Pfizer have asked the FDA to wait on further data (due around April).

 
Sanofi/GSK report that they are to seek regulatory approval (from the US FDA, EMA and others) for their 10µg two-dose AS03 (squalene) adjuvanted recombinant protein subunit COVID-19 vaccine, VAT08, which expresses spike (stable at standard refrigeration temperatures).

In their phase 3 primary series trial (>10k participants of 18+ years of age), two doses of the Sanofi-GSK vaccine in seronegative populations demonstrated:
  • 100% efficacy against severe COVID-19 disease and hospitalisations (zero cases in the study).
  • 75% efficacy against moderate or severe COVID-19 disease.
  • 57.9% (95%CI:26.5-76.7) efficacy against any symptomatic COVID-19 disease.
  • 77% efficacy against any delta variant associated symptomatic COVID-19 disease (analysis still underway).
  • high rates of seroconversion (>95%).
Additionally they demonstrated that when used as a third dose booster following a mRNA or viral vector two-dose primary series neutralising antibodies were raised 18 to 30 fold. The vaccine candidate had a favourable safety profile whether used as a primary series or a booster.
Geometric mean titres for pre- vs post-booster neutralising antibody titres in 18-55-yr old participants. Geometric mean titres for pre- vs post-booster neutralising antibodies in ≥56-yr old participants.

 
In other vaccine related news...

Novavax have begun shipping their Nuvaxovid recombinant, adjuvanted protein subunit vaccine, NVX-CoV2373, to a number of EU member states where it has be authorised for use in persons 18+ years of age.

Valneva have been awarded £20 million of funding by Scottish Enterprise for further research and development of their inactivated, whole virus COVID-19 vaccine candidate, VLA2001, and other Valneva vaccines. Discussions between Valneva and the Scottish government have included the potential supply of VLA2001 to Scotland in the future, subject to regulatory approval.
 
Extended UK trials data for Novavax NVX-CoV2373 indicates that efficacy to any infection, even asymptomatic (as measured by PCR positive test or anti-nucleocapsid antibodies), was sustained at 82.5% (95%CI:75.0-87.7) for 6 months against all variants (for the trial data collection period Nov202-May2021). This compares to 89.7% (95%CI:80.2-94.6) over the original first three months of the trial, and is significantly less than any other approved vaccine. Efficacy against severe disease was 100%.
 
I see the picture of waning immunity has evolved a bit in the latest vaccine surveillance report. I dont really have time to get into detail now but their attempts to look at effectiveness in regards hospitalisation seems to have improved in quality because they are trying to make a distinction between several different definitions of hospital treatment.

There is also a handy graph showing how many hospitalisations over time they think there would have been during the Omicron waves if there had been no boosters.


Screenshot 2022-03-25 at 15.14.jpg

Screenshot 2022-03-25 at 15.13.jpg
 
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