Even if the alternative is minimal exposure but regular vaccination? I would have expected that to give most of the immunity boost at significantly lower risk.
One thing I’m not clear on is the effect of exposure that doesn’t lead to a detectable infection. (I mean a situation where a person has definitely breathed in or otherwise ingested some virus particles, but they don’t last long enough or multiply sufficiently to cause symptoms or register on a test.) My current impression is that it probably tends not to make any significant difference to the body’s ability to deal with subsequent exposures, but I haven’t seen strong evidence either way. (It seems like observational studies would struggle to distinguish between those casual contacts who breathed in some virus and those who didn’t; and for household contacts who ~certainly must have got some virus in them, but didn’t get infected, it would be hard to tease out the protective effect of this exposure from the selection effect.)
Even if the alternative is minimal exposure but regular vaccination? I would have expected that to give most of the immunity boost at significantly lower risk.
One thing I’m not clear on is the effect of exposure that doesn’t lead to a detectable infection. (I mean a situation where a person has definitely breathed in or otherwise ingested some virus particles, but they don’t last long enough or multiply sufficiently to cause symptoms or register on a test.) My current impression is that it probably tends not to make any significant difference to the body’s ability to deal with subsequent exposures, but I haven’t seen strong evidence either way. (It seems like observational studies would struggle to distinguish between those casual contacts who breathed in some virus and those who didn’t; and for household contacts who ~certainly must have got some virus in them, but didn’t get infected, it would be hard to tease out the protective effect of this exposure from the selection effect.)