[justwanttolearn]

"But Varaka said he was told by his employer that immediate revaccination was his only option, and he won't be able to get an extension."

This is scary, we don't know what mixing shots and so soon will do to a person. At this point this is hardly about public health anymore, to not even be able to grant exemptions like this.

[dredmorbius]

Current understanding is that the practice isn't harmful (safety) and may benefit (efficacy), the two key concerns of drugs trials. See (from August 12, 2021):

https://www.msn.com/en-us/news/world/what-we-know-so-far-abo...

WHO was recommending against as of July, 2021, though based on a lack of evidence rather than evidence of harm or lack of efficacy.

https://www.msn.com/en-us/health/medical/who-warns-against-m...

The question is being investigated currently:

https://www.nih.gov/news-events/news-releases/nih-clinical-t...

"We don't know" alone is not a valid reason for discouraging a practice where there's no clear indication of harm and where understanding is being actively developed. There's an absolutely valid basis for taking a probablistic risk-based approach based on likely benefits vs. costs.