Overview of the Main Anti-SARS-CoV-2 Vaccines: Mechanism of Action, Efficacy and Safety; Mascellino et al 2021

[SNT Gatchaman]

Overview of the Main Anti-SARS-CoV-2 Vaccines: Mechanism of Action, Efficacy and Safety
Mascellino MT, Di Timoteo F, De Angelis M, Oliva A
Infect Drug Resist. 2021;14:3459-3476.

Published 2021 Aug 31
DOI 10.2147/IDR.S315727
Full Text

 

[Trish]

Abstract:

This review takes into consideration the principal vaccines developed against the SARS-CoV-2 in this unprecedented period of Covid-19 pandemic. We evaluated the mechanism of action of each vaccine as well as the efficacy, the safety and the storage temperature. In addition, the problem of the dose units, the vaccinal strategy, the activity of alternative compounds such as the monoclonal antibodies and especially the issue of the virus variants were also described in detail.

Four vaccines are currently used in Italy: Pfizer-BioNTech mRNA BNT162b2 (Comirnaty) (USA), Moderna mRNA 1273 (USA), Astra-Zeneca ChAdOx1-S (recombinant) viral vector adenovirus belonging to Oxford (UK) and Pomezia (Italy), Janssen (two recombinant viral vector adenoviruses) belonging to Johnson & Johnson (USA).

The efficacy of Pfizer and Moderna for preventing disease or severe disease results 95– 87.5% and 94.5– 100%, respectively. The efficacy of Astra-Zeneca and Janssen is about 70% and 65%, respectively; in the case of Janssen, it depends on the geographical area ranging from 72% to 57%.

The problem of the administrated doses (one dose, two doses from the same vaccine or from different vaccines, half dose) is also discussed. The vaccination strategy based on the age group remains the simplest, most transparent and fair criterion. This strategy is also based on accelerating the administration of the vaccines, so that as many subjects as possible can be vaccinated quickly for achieving the “herd immunity”.

The monoclonal antibodies appeared to be a valid solution for the treatment of Covid-19 disease. Two antibodies (bamlanivimab and etesevimab) have just been approved by the FDA. They could also be used for the infection by virus variants which represent a big problem due to their higher transmissibility and virulence and to their lower response to the vaccines.

 

[Sisyphus]

"The efficacy of Pfizer and Moderna for preventing disease or severe disease results 95– 87.5% and 94.5– 100%, respectively. "

That sounds like the efficacy for the original strain and not the following variants.

 

[Snow Leopard]

This is one of the worst reviews I have read for quite some time.

The information is out of date, they don't bother to provide any explanations for the differences in efficacy between the vaccines, reasons for waning or mechanisms for the serious side effects (GBS, TTS, myocarditis). Under "Mechanism of Action", the authors explanation of how B-cells generate antibodies is a confusing mess.

There are plenty of errors.

Just a few of many examples:

Proteins then achieve the cellular membrane and evolve in two types: the MHC-2 (antigen presenting cells) and the MHC-1 related to another antigen which is present in all the nucleated cells of our body.

What?

side effects such as the syndrome of Guillain-Barre and anaphylactic and allergic reactions even though very rare, have been reported in literature for the vaccine Pfizer. 15,16

Of course reference 15 is an error because it has nothing to do with COVID vaccines and the sentence doesn't make sense.

There was no major difference in the levels of antibodies elicited by Pfizer or AstraZeneca vaccines.53

Again, this is wrong. The cited study didn't even discuss AZ/Chadox and there are differences in antibody levels.

Whoever wrote, edited and peer-reviewed this mess needs to take a long hard look at themselves because they failed to do their job.

 

[SNT Gatchaman]

Thank you @Snow Leopard. A shame the paper had these substantial flaws — I had hoped it might be a reasonable reference for the different vaccine types and mechanisms of action. It seemed to be basic and approachable, with some diagrams and also helpfully included the phase I-III approach in a side-bar. Perhaps we can simply refer to the Wikipedia entry.

I probably should have thought twice about posting it, given that I chopped out the abstract I had originally prepared from the initial post, as I thought it was too distracting and "off-message". Sorry @Trish!! Perhaps if we come across a better paper we can replace this thread.

 

[Trish]

I probably should have thought twice about posting it, given that I chopped out the abstract I had originally prepared from the initial post, as I thought it was too distracting and "off-message". Sorry @Trish!! Perhaps if we come across a better paper we can replace this thread.

It's good that the weaker stuff gets posted here too, so we can learn about the weaknesses and not be misled by media hype when bad research is published.