[dilyevsky]

That’s not vaccination that’s inoculation which is how they originally prevented smallpox before they developed an actual vaccine

[vikramkr]

Its responsive to the parent question in that yes, we can have symptomless exposure to the infectious agent (or some part of it) and develop immunity. Maybe the distinction between using unweakened live pathogens and weakened or fragmented pathogens should have been emphasized but that didn't seem to the important part of the question

[dorfsmay]

Thanks, that was indeed my question.

It'd be interesting to understand if that's true for all viruses and in what quantities.

For example, in the early days of COVID, we were told that being close to infected people outdoor did not expose us to enough viruses to get infected. Could such exposure have provided immunity?