I've had all the vaccines, and have had Covid two times - all mild. The most recent one, two years ago, was so mild that my only symptom was apathy, which shocked me, because by nature, I tend to care about everything! I wouldn't have guessed it was Covid if it hadn't been the fact that I'd been to a family event where so many people got it that I tested myself, and was positive. A month or so after that, the 'brain fog' - confusion, memory loss, inability to stay on task, and serious depression set in. For six months, I couldn't work, got lost driving, forgot how to do the simplest things like turning my car off, and wasn't always sure what a red light meant. It gradually improved, 'tho I would have weeks when it would return.
Recently, I had a setback and was again confused and often unable to finish sentences. My work suffered, and I thought I'd need to quit again.
Two weeks ago, I got a Covid vaccine. It did its usual thing with me, putting me to bed with chills and body aches for 24 hours. Two days later, I felt both physically and mentally like I haven't felt in two years. My thinking is organized and clear, and I can learn new things and actually remember them!
The immune system is so complex, and every person with LC experiences it somewhat differently. It's hard to make generalizations about what works and what doesn't. I do believe that my sudden improvement was probably related to getting the vaccine, but I also understand that it wouldn't necessarily work for everyone.