That's a great question...because that is what the stats show.
Here's another....Suppose you already had it and you/they didn't know. Will it backfire?
You can be pretty sure they never had such persons in their studies.
and here is another wrinkle:
WAKE UP AMERICA!!!!
who counts votes for elections WW, AND is a major supplier of COVID tests WW???
As a participant in the Moderna study, they take blood tests at every visit, the first a long visit where they took a very complete medical history and when the first shot is administered, the second a month later when the second shot is administered, and the third visit another month later with follow up questions. Eight vials of blood, some of which is tested at the time and some of which is stored for later comparisons or analysis as more testing is likely developed. I am sure they know if a participant has had it, they also did the nasal test during the first two visits. They keep tabs on whether any symptoms arise and will track for two years with questions and occasional visits.
I don’t know if I got the vaccine or placebo, but the first shot was a little sore for a few days like after a tetanus shot. Second shot no pain. No symptoms after either shot.
I started traveling quite a bit after starting the study and hope I got the vaccine due to a lot of exposure in the airports and planes. Flying about once a week.
Statistically speaking there should be asymptomatic people in the study and there were no adverse effects.
Will what “backfire”? And what does that even mean in this context?
If you give a vaccine to someone who is already immune, their immune system rapidly destroys the “invading” vaccine. That’s what happens: basically nothing. It’s a waste of a dose is all.