What can cause no antibodies to develop after a moderna or pfizer mrna vaccine?

There is no reason to test for antibodies following vaccination. Patients on immunosuppressive treatment may not produce detectable amount of antibodies. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs.

If you do the wrong test you will not find antibodies. Wild covid disease produces specific antibodies to the whole virus. The vaccines stimulate antibodies only to the spike material it simulates. Tests for the vaccine associated antibodies are not preformed on a routine basis.