How closely related are SARS 1/2 and Mers to the four coronaviruses that cause (a small minority of) the common cold, could we be gaining partial protection from them too?

2020 called and wants her easy questions back! ;)

Immunity to cold viruses is so prevalent, there is no chance the effect is pronounced, by now. It has been researched tho, so you may find some studies discussing the issue.

I think you misunderstood their question. Obviously immune response to common cold isn't effective against rona. But if this vaccine is effective against a wide range of coronaviruses, could it also be effective against the one that causes the common cold?

Ah. Thanks for clearing that up! That makes a lot more sense in hindsight.

On the other hand, the cross-immunization to SARS1 and MERS is not surprising, since the mRNA vaccines were developed for these and modified for SARS2. (It is not a completely novel vaccine and "rapid development" was only possible, because a lot of basic research was already done on SARS1/MERS. Would have taken a lot longer to identify a molecular target otherwise.)

>Obviously immune response to common cold isn't effective against rona.

Actually...according to some studies it is.

https://www.nih.gov/news-events/nih-research-matters/immune-...

Well, the Clalit preprint relying on more data by an order of magnitude will be out soon, and that should be the definitive analysis.

However, current results for a Pfizer 1st-only regiment aren't very encouraging IMHO. It's possible the first dose starts to be really effective exactly at the time Pfizer suggested to have the second dose, and that this increase is rather sharp - But it would be some coincidence, and antibody tests (showing not so good efficiency against variants following 1st dose, and also much larger antibody count after 2nd dose) are contraindicative.

Didn’t Israel test antibody levels post-1st dose, and come out with results that it’s around 50% by week 2 and 90% by week 3, before taking the second shot?

If I’m not mistaken the claims that the levels are low (and efficacy only 50%) were because some sources took average of days 1-21 instead of 14-21.

I'm not sure what your 50% and 90% refer to. 50,90 percent of what? There were tests showing an order of magnitude more antibodies a week following 2nd shot (e.g. [0]).

The efficacy claims were because disease levels took more time to drop off than what one would expect following lockdown+start date of 1st shot vaccination if 1st shot were effective. I lack the qualifications to evaluate these claims, but I can tell you all Israeli HMOs prefer the 2 shots regimen.

[0] https://twitter.com/ArielMunitz/status/1356683799568990216

Those percentages are percent of vaccinated people who have not been observed with symptoms

Isn’t the Moderna vaccine dose larger?

True, but I am not sure that changes things. It's possible that the dose increase doesn't lead to a relevant clinical difference.

Ultimately, someone will have to do real world analysis and get conclusions from that. Right now, IMHO, there's better reason to think that a smaller Moderna dose is fine than to trust a single shot Moderna vaccine regiment.

I mean we have over 1 million cases now how much more of a sample size do you need?

Pfizer-BioNTech (it's the GNU/Linux of vaccines)