I had the 2 Pfizer's at the beginning of the year. Antibody test showed 0 antibodies after those vaccines. I had the Moderna over 4 weeks ago. We tested my antibodies again.... And it's still at 0. Like I never even had any darn shots. I am so freaking out.
We will need more information. Antibodies are generated against different proteins (antigens) and there are different classes of antibodies (IgA, IgM, IgG) against each of the antigens (foreign proteins) that your body fights.
Vaccination with Pfizer, Moderna, AstraZeneca and Janssen will generate only antibodies against S (spike) protein as these vaccines force your body to produce S (spike) antigen.
Infection with live virus will generate antibodies against multitude of viral proteins, including against both N (nucleocapsid) and S (spike) proteins.
On average about
3-4 days post challenge, your immune system starts to generate antibodies. The first classes of antibodies that can be detected are IgA (which protect mucous membranes), followed by IgM and IgG. It takes about
2 weeks before IgG class antibodies can be detected by most serology tests.
So if you had vaccines and tested only Nucleocapsid antigen antibodies, then you'd get 0.
If you had vaccine and tested Spike antigen antibodies and they were 0, then it means you're one of the unlucky ones that doesn't mount antibody response.