The critical path is microfluidics and machines to make lipid nanoparticles. It's likely these paths are ramping as quickly as possible.
There's no use of intact animals to make these vaccines. I don't think there are any use of animal cell cultures in any of the mainline vaccine paths (though there are some human cell lines used in the adenovirus, etc, vaccines that many people consider problematic).
Oh, well, sure. But the COVID vaccines even at peak production will likely only be using a single digit percentage of the endotoxin tests done in the US in a typical year. In no way can this be considered limiting.
About 60k doses/lot, figure 30 endotoxin tests per lot, that's 1 test per 2k doses =~ 300k endotoxin tests to vaccinate the US.
I guess I can't say I've read them closely, but I don't recall any of the recent articles about the crabs having figures like that (which it is good that it isn't a problem, I'm referring to the articles not getting to the important bit about it not being an issue).
"For now, the industry says it has plenty of horseshoe crab blood to screen coronavirus vaccines. Pharmaceutical companies test a sample from a batch of vaccines, not every dose. And that sample size, say three vials, doesn’t change whether the batch contains 100,000 doses or 1 million, says Allen Burgenson of Lonza.
In fact, Burgenson says, the industry produces enough tests in one day to screen 5 billion doses of coronavirus vaccine."
(I think this is unduly optimistic, because mfrs are likely to screen at multiple steps during production, since the latency of batches is ~100 days, and because lot sizes aren't so large yet. So divide 5 billion by a small integer).
There's no use of intact animals to make these vaccines. I don't think there are any use of animal cell cultures in any of the mainline vaccine paths (though there are some human cell lines used in the adenovirus, etc, vaccines that many people consider problematic).