I've heard from someone that the mRNA vaccine from Pfizer doesn't prevent people from being infected and contagious, it just kinda mitigates the effects of the virus.
I had no sources, I don't know if it's true. Does someone have info on this ?
Pse. I've read something similar, but not quite the same. It's not that the Pfizer/BioNTech vaccine doesn't prevent infection, it's that it is not currently known whether it prevents infection, because the trials were designed to test for symptoms, not infection.
It seems they didn't test the test participants every week or so with a PCR, they just waited until someone complained of symptoms and then made PCR test, looked at everything and made diagnostics. Then (after a prefixed number of complaints) they counted how many of them had had placebo and how many vaccine. So they can deduce that those with the vaccine complained less of symptoms, but they can't know if they had the virus or they passed it away.
I read it in forbes, i think it was
here, but I lack the expertise to evaluate how much sense it makes.
Nobody knows. Nobody's going to be exposing people who've taken the vaccine with live virus just to prove it works. So we need to wait until enough people have been vaccinated and see what happens.
Somebody who worked at Pfizer
warned others wanted to do just that, I don't know if they're yet going to do it. I've heard the WHO is going to discuss it in some meeting. It doesn't sound right to me.
That's part of the reason they didn't PCR-test test participants systematically. If you can't infect healthy vaccinated people because you don't know the vaccine works yet, and you don't know how to cure them, then you can only wait for they to get infected naturally and compare numbers between control group and test group. But if you do so, then you want to test in regions with a high natural spread of the virus, so that you get significant numbers of naturally infected participants sooner. I guess in those regions they have enough of a problem already
with coping with the pandemic to have them testing test participants each week and determining infection. So they wait for symptoms. Although I've read
a subgroup of AstraZeneca/Oxford participants were tested for infection too.