Thread by @jacquesenboit

@drcaromers @YouAreLobbyLud erj.ersjournals.com/content/18/3/5…
This review from 2001 tells the what, how, where of secreted dimeric igAs.
It's literally the first line of defense for both upper & lower respiratory tracks.
For a vaccine project to abandon the 1st line of defense is just unbelievable.

@drcaromers @YouAreLobbyLud Especially for a virus that is known to tunnel directly from one cell to the next, the mucus is the only battlefield that the virus need to really get pass Abs. Once inside the cell, it just need to propagate from to the adjacent cells by syncytia. No amount of systemic

@drcaromers @YouAreLobbyLud ...Abs is going to stop it, bcoz it doesn't have to come out to the extracellular fluid to meet the Abs.
With Delta, you got 2 enhancers to this problem :
(1) the viral load is 1000x, which means if 300 virion particles was the median to get infection, now it's 1!! IOW,

@drcaromers @YouAreLobbyLud ...every one virion particle that gets into the lung can infect a cell. An infected person emits thousands of virion particles <5um with each breath. Inhaling the cloud around will bring in thousands. And each infected cell will serve as a base to tunnel to many cells.

@drcaromers @YouAreLobbyLud (2) Delta is even better than the older variants at forming syncitia. And good at doing the same to T cells, which form the main component of adaptive cellular response. So not only the vaccination is losing effectiveness of the Abs, it's losing the cellular defense as well.