[FreakyT]

We know that they trigger an immune response, but that alone doesn't necessarily mean much.

For example, an early SARS vaccine candidate triggered an immune response in tests, but that immune response in practice actually made SARS infections worse.[1]

[1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3335060/

[shajznnckfke]

Yeah, certainly we ought to see how animals and people with the vaccine react when exposed to the virus, but have we not already done that in the months these vaccine candidates have been tested? The current trials did things like give the vaccine to thousands of Brazilian health-care workers, which should have uncovered any issues like that (in the article you linked, the issue was uncovered by testing in a small sample of animals).

[pwinnski]

We have a process with three stages of trials. No vaccine candidate has yet gone through all three stages, no.

[shajznnckfke]

What I’m arguing is that we don’t need complete phase 3 trials to establish efficacy - we can establish that based on early data from those (and earlier) trials, while accepting larger error bars on the risk of side effects.