Vaccinated folks prevention of spread

[anes121508]

My understanding is that some vaccines prevent infection but not spread. I’m far from an expert and it’s been a while since immunology

What determines that?

How likely is it the mRNA vaccines prevent spread?

How long till we have data on this?

any decent reviews on this concept?

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[coffeebythelake]

My understanding is that some vaccines prevent infection but not spread. I’m far from an expert and it’s been a while since immunology

What determines that?

How likely is it the mRNA vaccines prevent spread?

How long till we have data on this?

any decent reviews on this concept?

Well I imagine if the vaccine prevents you from getting the virus, it also prevents you from giving it to others

 

[LineAndBerry]

Should you take the COVID-19 vaccine? | Suneel Dhand

suneeldhand.com

 

[DrN2O]

I think you may be referring to mucosal immunity vs. systemic (circulating ab) immunity. Some people believe the mRNA vaccines may induce the latter but not mucosal. This could in theory allow SARS-CoV2 to survive and replicate in your upper respiratory tract and spread to others, without infecting you and causing more severe disease. This is the advantage of intranasal flu vaccine in theory, and immunity from natural infection. Only time will tell, but not sure if the current phase 3 trials will address that.

 

[coffeebythelake]

I think you may be referring to mucosal immunity vs. systemic (circulating ab) immunity. Some people believe the mRNA vaccines may induce the latter but not mucosal. This could in theory allow SARS-CoV2 to survive and replicate in your upper respiratory tract and spread to others, without infecting you and causing more severe disease. This is the advantage of intranasal flu vaccine in theory, and immunity from natural infection. Only time will tell, but not sure if the current phase 3 trials will address that.

Huh, that's interesting

 

[GassYous]

I think you may be referring to mucosal immunity vs. systemic (circulating ab) immunity. Some people believe the mRNA vaccines may induce the latter but not mucosal. This could in theory allow SARS-CoV2 to survive and replicate in your upper respiratory tract and spread to others, without infecting you and causing more severe disease. This is the advantage of intranasal flu vaccine in theory, and immunity from natural infection. Only time will tell, but not sure if the current phase 3 trials will address that.

At first I was like wtf when I read the op but I did learn about this in medical school

 

[DoctwoB]

I think you may be referring to mucosal immunity vs. systemic (circulating ab) immunity. Some people believe the mRNA vaccines may induce the latter but not mucosal. This could in theory allow SARS-CoV2 to survive and replicate in your upper respiratory tract and spread to others, without infecting you and causing more severe disease. This is the advantage of intranasal flu vaccine in theory, and immunity from natural infection. Only time will tell, but not sure if the current phase 3 trials will address that.

This. It may or may not prevent you from being an asymptomatic carrier. Smart money says that you will be significantly less infectious even if not completely non infectious but that's just a guess at this point with the mRNA vaccines.

The Oxford-AZ trial did screen for asymptomatic infection and found it was ~60% reduced in the more effective half dose/full dose regimen (which was 90% effective in preventing symptomatic infection) and only 4% reduced in the full dose/full dose regimen (which was ~60-70% effective in preventing symptomatic infection). This would suggest that the effective vaccines prevent asymptomatic infection but less so then symptomatic infection. Obviously AZ/oxford and Pfizer/Moderna are different mechanisms so that may or may not apply across mechanisms. On the other hand, just because you can detect virus on a nasopharyngeal PCR doesn't mean that the vaccine didn't make you much less infectious by reducing the viral load compared to those without vaccine.

TLDR: It likely makes you less infectious, but probably not 100%. More data needed.

Hopefully now that we'll have over a million people vaccinated Pfizer or Moderna is running some study to assess infectiousness.

Edit: Apparently there is some asymptomatic data in the Moderna trial. They tested for asymptomatic infection between dose 1 and 2 and found a ~2/3 reduction. ACIP Evidence to Recommendations for Use of Moderna COVID-19 Vaccine under an Emergency Use Authorization | CDC. This was just a one time swab, not ongoing surveillance, it sounds like. One could reasonably expect that if was reduced by 2/3 between dose 1 and 2 it would be reduced even further after dose 2.