The study seems flawed. It tested for antibodies in the non vaxxed, but my understanding is that the vax doesn’t contain or produce antibodies. Both the vaxxed and non vaxxed in this study likely obtained the antibodies naturally through Covid infection.

Also…

Mr. Hooker said the study suggests that if Ig antibodies can be transmitted person-to-person, there is a possibility the spike protein generated by COVID-19 vaccines could be transmitted as well.

They acknowledged that they didn’t test the spike protein, and it’s hypothetically possible it can be transmitted.