Correct, I misinterpreted. Found a paper on the CDC website. Antibody tests exist and can identify 85-90% of prior asymptomatic or mild covid infection after 8 months, but there is no $5 antibody kit yet. I know, small sample size, this is the best I can do.

> We analyzed data from 7 participants with asymptomatic SARS-CoV-2 infection and 51 patients with mildly symptomatic COVID-19 (Table 1). Eight months after their infections, we detected anti-N pan-Ig in 53 (91.4%), anti-N IgG in 15 (25.9%), anti-S IgG in 50 (86.2%), and anti-S1 IgG in 40 (69.0%) (p<0.01) (Table 2).

Translation: We could spare you the trouble of getting a vaccine by performing an antibody test, but these tests are labor intensive and we are swamped. We'll just pretend these tests don't exist, assert that taking the vaccine is good for you in all circumstances and mandate you take the vaccine anyways.

https://wwwnc.cdc.gov/eid/article/27/3/20-4543_article

https://wwwnc.cdc.gov/eid/article/27/3/20-4543-t2

Edit. It should be mentioned that EU permits the use of prior covid infection evidence for their covid passport initiative, though does not permit antibody tests for the purpose.

> The EU COVID Vaccination Passport will be issued to all those who have been fully vaccinated against the Coronavirus, with one of the four vaccines approved by the European Medicine Agency

> Travellers who have recently been infected with COVID-19, and recovered from it, should also be permitted to travel with an EU COVID travel certificate

> However, the Commission also points out that tests that detect if a person developed antibodies against SARS-CoV-2 – also known as antibodies tests – cannot be used to obtain a recovery certificate.

https://www.schengenvisainfo.com/news/all-details-on-eu-covi...