I had spinal meningitis as an infant. Did that make me immune? Or did it make me more susceptible?
Johnny, I don’t know, but thought I’d bump this up. Meningitis can be caused by various pathogens, bacteria or virus. In addition, there are non-pathogen causes. I doubt if it would make you more susceptible, but don’t forget that memory cells (no pun intended) are not forever; so any immunity you may have had to the pathogen no longer exists.
Meningitis is generally not caused by the same pathogens in infants and adults. Most likely even if you had lasting immunity to the pathogen which caused it as an infant, you would not be immune to adult meningitis (meningites? menigitides?).
Meningitis indentifies the location of infection, not the pathogen. You might do better against that specific bug, but probably not after all this time.
I suppose you could postulate some scar tissue from the original infection the created a weak spot that increased your risk of infection, but that’s going way out in left field.
Bacterial meningitis (the kind most lay people are talking about when they say “meningitis”) results from a combination of pathogen and altered host defenses.
As a rule of thumb, survival from exposure to a pathogenic bacterial strain will result in some protection (improved host defense) for a variable period of time that tapers off as the months and years go by. Immunizations and boosters work on the same principle.
Bacterial meningitis is caused by a number of organisms. The type of organism clusters around the period of birth, early childhood and adults. For instance, Hemophilus B is more common in childhood while Strep Pneumoniae and Neisseria strains are more common in young adults. Each broad category can have individual strains.
If your immune system (host defenses) are intact, you might have a little residual immunity if you get re-exposed to the same bacteria, and in particular the exact same strain. However if your immune system has a defect, you might be more susceptible on re-exposure because the immune cells have expired and the defect remains. As an example, it’s thought that some folks who get bacterial meningitis with Neisseria strains have a defect in part of their host defense mechanism called complement deficiency. Such an individual is more likely to get meningococcal meningitis in the first place, and down the road the immune system cells which were marshalled for defense after the first infection may have expired. That individual is more likely to get meningitis again because their immunity has worn off and their defect is permanent. It’s not that the original infection made him more susceptible; it’s that the original infection demonstrates the underlying susceptibility.
Most of our susceptibility–even to serious diseases such as meningitis–is related to host defenses. For example, it’s very common to walk around perfectly healthy as a totally asympomatic “carrier” with strains of Neisseria Meningitides happily growing in your nose and pharynx. Only a small fraction of people exposed to that organism will actually develop disease.