It absolutely is true. Antibody production declines at an exponential rate(1). You don’t lose your immune response quickly, because T-cells and the like “remember” the virus—but your body doesn’t waste energy producing antibodies forever when there is no active need to have them around.

https://www.nejm.org/doi/full/10.1056/NEJMc2025179

Late edit: if you think you’ve lived through a sars-cov-2 infection, get it in writing within a few months.

This confuses false negatives with true positives. If someone can produce a positive antibody test, it means they had covid, period. As such, they don't need the vaccine.

The credibility problem arises when people are so gungho into pushing vaccines onto everyone, whether they need it or not, that they willfully ignore any possible alternative.