Many medications and vaccines are known to cause immune disorders, previously diagnosed or not, to "relapse", "awaken", or otherwise get worse.

I suspect I always had mine, Hashimoto's Disease, which wasn't diagnosed until after the Modern put me in the ER and gave me a year of debilitating medical problems and pain, that still continues. I had a treated thyroid disorder for the longest time, but I never had been near death on a weekly basis, from it and yet to be diagnosed mystery problems, until the vaccine.