CharonY Posted December 15, 2020 Posted December 15, 2020 7 minutes ago, studiot said: As to whether the Pfizer vaccine is dead virus or fragments of virus is a bit of a pointless argument. If I gut and fillet a dead fish for the table, it is still a dead fish (but with bits missing). If I hold a hog roast the thing turing on the spit over the firepit in the garden is still a dead pig (but with bits missing). But if I put a loin joint of pork in the oven, that is fragment of pig. I understand the difference between the Pfizer and Oxford vaccines are the difference between my fish or hog roast and sticking the legs off a pig onto a turkey. Actually no, the mechanism to how they are generated are so vastly different that it has severe impact on their effect and production. In short a RNA vaccine holds the promise of rapid vaccine development. Once you sequenced a virus you could just identify an unique stretch, synthesize it and put it into a lipid shell. An attenuated vaccine requires to cultivate and purify the virus, inactivate them in a way to render them harmless but still retain immunogenicity (which is tricky and takes a long time). Using parts of the virus requires again a genetic step but then you still have to express the protein in vivo or in vitro, purify it and then use the resulting product as a vaccine. Think about it that way, instead of raising a pork and roasting it, or even just cut off pieces of it (which is actually not a a good example, it is more like raising just a leg instead of a whole pork) you just take a picture of a hog, and then use the digitized information to print out something that you can just eat (yes, stupid analogy, but it is that different). All antigen production happen within your body now, instead of requiring to produce them. 1
Area54 Posted December 15, 2020 Posted December 15, 2020 3 minutes ago, CharonY said: Actually no, the mechanism to how they are generated are so vastly different that it has severe impact on their effect and production. In short a RNA vaccine holds the promise of rapid vaccine development. Once you sequenced a virus you could just identify an unique stretch, synthesize it and put it into a lipid shell. An attenuated vaccine requires to cultivate and purify the virus, inactivate them in a way to render them harmelss but still retain immunogenicity (which is tricky and takes a long time). Using parts of the virus requires again a genetic step but then you still have to express the protein in vivo or in vitro, purify it and then use the resulting product as a vaccine. Think about it that way, instead of raising a pork and roasting it, or even just cut off pieces of it (which is actually not a a good example, it is more like raising just a leg instead of a whole pork) you just take a picture of a hog, and then use the digitized information to print out something that you can just eat (yes, stupid analogy, but it is that different). All antigen production happen within your body now, instead of requiring to produce them. A useful and effective analogy. I am now better informed. Thank you.
Duda Jarek Posted December 26, 2020 Author Posted December 26, 2020 Tomorrow EU starts mass vaccination https://www.france24.com/en/europe/20201226-european-union-begins-coronavirus-vaccine-rollout-as-new-strain-spreads ... as the new strains like UK's are quickly spreading - what do we know about vaccine efficiency for them? It is great that there are lots of them - covering various mechanisms, hopefully allowing for effective war with mutations (https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html 3 approved, 5 limited approved, 18 in phase III). Very nice explanation of Pfizer mRNA vaccine: https://berthub.eu/articles/posts/reverse-engineering-source-code-of-the-biontech-pfizer-vaccine/, especially: - it uses Psi (1-methyl-3’-pseudouridylyl) instead of U (uracil) - works the same, but with weaker immune response, - uses synonymous codons with increased numbers of C and Gs (e.g. CUU -> CUG both encode Leucine), which are converted more efficiently into proteins, - two amino acids are changed comparing to virus spike protein (K,V -> P) to handle the problem of difference between pre- and post-fusion spike protein - this exchange into Proline makes them fold into the proper shape without being mounted to a virus (known since 2017 thanks to work on SARS-CoV-1).
Duda Jarek Posted January 7, 2021 Author Posted January 7, 2021 (edited) On 12/26/2020 at 10:08 AM, Duda Jarek said: as the new strains like UK's are quickly spreading - what do we know about vaccine efficiency for them? Obviously many are coming, naturally selected especially for faster spread, now e.g. also from South Africa: https://www.cnbc.com/2021/01/06/south-africa-covid-strain-a-guide-to-what-you-need-to-know.html Again good interview: Edited January 7, 2021 by Duda Jarek
CharonY Posted January 7, 2021 Posted January 7, 2021 Not sure what the videos says, but mutation in the gene for the spike protein are concerning. No conclusive evidence either way, yet. 1
CharonY Posted January 8, 2021 Posted January 8, 2021 Adding to that, the Moderna CEO announced that their vaccine is likely effective against the Sourh African and UK strains. However, no data has been forthcoming (yet).
zapatos Posted May 22, 2021 Posted May 22, 2021 I'm in no position to evaluate the veracity of this article but it seems to indicate that the MMR vaccine may be responsible for lessening the impact of COVID-19 on people. In part, the more recent the MMR vaccination, the less likely you are to have a severe reaction to the disease. Hence, younger people are impacted by COVID-19 less than older people. Quote It has been theorized that the measles-mumps-rubella (MMR) vaccine may protect against or reduce the severity of coronavirus disease 2019 (COVID-19) infection (1–5). Gold et al. introduced this theory in March 2020 after observing that recent, large-scale MMR vaccination campaigns were associated with countries with the fewest COVID-19 deaths (6). https://mbio.asm.org/content/11/6/e02628-20
CharonY Posted May 23, 2021 Posted May 23, 2021 I only glanced through it so may have missed some dinner points. It seems interesting, but considering the end points measured, the cohort is too small and needs to be much more age stratified. Titer and disease severity correlate with age.
pl709 Posted June 26, 2021 Posted June 26, 2021 Some pretty nice evidence that history of MMR or Tdap vaccination yields better outcomes in patients infected with COVID with T-cell mediated protection: "Protective heterologous T cell immunity in COVID-19 induced by MMR and Tdap vaccine antigens" https://www.biorxiv.org/content/10.1101/2021.05.03.441323v1 https://www.alviss.ai/fullpage/2356220/3 The study has enough power and propensity matching seems to have worked. I would have appreciated p-values in the table 2 though.
Recommended Posts