I'd personally be extremely cautious of a rebuttal in a twitter thread rather than a professional rebuttal which is how these sorts of things should be sorted out in the scientific world. A twitter thread to rebut a peer reviewed paper actually makes me sad that this is where scientists go during a period where we need their input more than any other time.

Also, fwiw I followed antibody testing studies for the better part of a year and anything over 0.004 IFR was rare. I was surprised to see it as low as 0.0014 from this review expecting close to 0.002-0.003 but 0.0068 is incredibly high.