08-01-2021, 01:39 PM
Janit wrote:
[quote=PeterB]
I don't know too many patient populations for whom the vaccines are contraindicated at this point? (Especially with the mRNA vaccines, where it's not even a viral particle in the vaccine...) But hopefully herd immunity would keep infections in such individuals limited, and/or they could be treated with donated antibodies. My real concern (as I've stated here many times) is that we're going to end up with Delta Plus (as India already has) or Delta plus plus, eventually leading to an Omega, where Omega evades all current vaccines. This virus mutates more and faster than would be expected for a run-of-the-mill coronavirus.
Rather than just "contra-indicated" I should have included immunocompromised, and any other population that can't mount a robust immunological defense, for whatever reason.
My issue here with the over-broad application of the concept of "herd immunity." The classical concept of herd immunity is that vaccination of the majority of a population will stop transmission of the virus to anyone else, and thereby protect even those who are not immunized.
We won't achieve herd immunity against delta until a vaccine is devised that will stop transmission of the delta variant. The current vaccine makes delta infections largely non-lethal, but does not reduce delta transmission anywhere near enough to qualify as herd immunity.
I agree. I also think though that it's a matter of reduction, rather than elimination, of transmission ... I think it'll be nearly impossible to prevent transmission of Delta. Rather, it may be possible to reduce the viral load sufficiently to the point where transmission will be minimized, and the only groups that might need to be worried are, as you say, the contra-indicated and immunocompromised (of which I myself am a member).
For anyone curious, here's an interesting graphic:
(... I see a lot of very nice potential targets there...)
(both of these are from here, which makes a very good read: https://www.nature.com/articles/d41586-021-02039-y)