Why not get a covid antibodies test first?

San Francisco CA

Description

Now, it is known that if one has already had covid once that they have developed antibodies and are unlikely to benefit from vaccination. With that, why don't we all just get a covid antibodies test first before running out to get potentially-lethal experimental mRNA gene therapy shots that have already killed 1000's? https://www.medrxiv.org/content/10.1101/2021.06.01.21258176v1