I think other countries (maybe England) are going to start recommending tetanus shot every 30 years. It's probably one of the biggest medical misconceptions that everyone has. The shot lasts for a very long time. Also the chance of getting tetanus is so low for the modern human (that doesn't work on a farm). You basically have to step on glass in soil that has cow feces all over it. Also they try to give you the tetanus shot when you have a deep cut even though it's too late at that point.

Maybe you had a recent exposure?

It's been more than a year since I catched what I believe was light covid and periodical tests show my antibodies count never falls and even grows slightly, keeping on the level slightly above what people get after vaccines.