Vaccine from live virus

May 30, 2020
If it really takes about 1000 covid-19 particles to start an infection, why not give healthy people a very small dose, say 50 or 100 particles initially, so the B-cells start learning to recognize it? These people would have to quarantine to avoid larger exposures or infecting others. Maybe they would need more and larger doses to build up enough memory B-cells to ward off a large infection later.

Could this approach be practical in a very short time from now? Shorter than current vaccine efforts because we already have the virus to treat with?

I realize this is probably a very naive question and the answer will be, yeah, that’s already how it works, and it just takes time to develop dose(s) and schedule. Also we’d need to somehow make sure people stay quarantined, even if they feel ok after a few days. I suppose quarantine could be enforced, but that’s pretty creepy and would get a lot of backlash. Multiply the lockdown protestors by 1000. Hard to imagine any politician sticking his/her neck out to support that.

Advantages with this approach:

1. immunity is developed without getting sick.

2. the population could be immunized in a planned and controlled fashion, damping infection spikes. This would ease the burden on health care.
Companies and big organizations (the military for instance) could rotate staff through this treatment. That predictability would help them effectively plan operations, finances, purchasing, production, major projects, etc. That would help them survive and thereby reduce unemployment and help the economy.


Assistant Community Manager
Staff member
Nov 12, 2019
I could be wrong on this, but that 1000 particles could just be the amount known to spread via a sneeze, as noted in Figure 1 of this study. I think the issue would be that the immune responses to any exposure at all to COVID-19 particles is wildly unpredictable. With so much variability in immune responses, my worry with this would be that it's incredibly difficult to expose people to the COVID-19 particles in a controlled way. The closest equivalent would be outright infecting them a la herd immunity, the efficacy of which is contested.


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