drrich2
Contributor
And how many other disease’s are you aware of that a vaccinated person becomes a host carrier?
One comes to mind, a bacteria rather than a virus so limited applicability. Staphylococcus aureus is a common bacteria that can do terrible things inside the human body, like cause septic joints (like if it gets in a joint and causes sepsis, then destroy it within 24 hours). Some strains are antibiotic resistant - often called MRSA (methicillin resistant Staph. aureus).
Problem: Some years back, it became common knowledge in health care settings that MRSA is fairly common in colonizing people's noses. Including staff. Oh, crap! How serious is this, and what to do?
It got a lot of attention for awhile...then over time seems like much less.
The E. coli common in the human colon can cause bad infections should it get in wounds.
People form antibodies to the HIV virus, and at least at times to the Hepatitis C virus, without ever clearing them from their systems, and can transmit them to others.
So, to address your question, a person can carry a potentially harmful microbe without suffering overt disease from it and may do so chronically.
Now, the applicability of bacterial samples to viruses, or HIV or Hep. C virus to this coronavirus, is quite a stretch, but my point is we can carry dangerous germs without being sick ourselves. I hope this coronavirus won't be one of them.
We also don't know how long effective immunity from vaccination or prior infection lasts, and how variable that duration is across individuals. What if it lasts a year for you but only 3 months for me? What if old people lose immunity much faster than the young?
Edit for clarity: Obviously people with HIV, and many with Hep. C, do suffer (at times fatally) from the infection, though in both cases presently asymptomatic people can transmit it to others.