Pertussis immunity from vaccination fades after a while; you should get the Tdap or other variant every decade when you get your tetanus shot. California had an outbreak a few years back, and a friend who was in her 40s or 50s got it, coughed painfully for 2 months, did not recommend the experience.

CDC recommends TDaP for "adults who have never received the vaccine." Are they wrong on this?

I had a healthy college student once who was recovering from pertussis. She had been sick for over 2 months. Even young, healthy adults can get sick.

Yah I got caught up in that outbreak. 0/10 experience. Exhausting to cough that much for that long. My cough muscles got so strong over the months that my coughs would rattle my spine.