There is not a single reference to a primary document or any verifiable testimony (not that concentration camp "survivor" testimony is particularily reliable).

The author is unknown beyond this site and half her articles are along the lines of "Top 10 battlefields of the Civil War".

The screenshot is from an obvious commie propaganda rag.

I'm willing to believe Pfizer was running experiments on prisoners, but this is a weak source and I would never use it to back up any argument against them.