Originally Posted by carriebft
Type B is different than the other types and causes different symptoms and issues. Thus, we can't conclude it is illogical just from saying tpye A is ont he rise because we have ousted B.
What are the effects of A? what is its virulence? What problems does it cause?
Is it better to have less B and risk having more A? (or C, d, e or f?-- i think they end at F)
that's a whole 'nother debate in and of itself. (IMO)
(and, obviously, it is an issue for the OP to look into- serotype replacement)
Just in case anyone cares...
HiA is almost identicle to HiB, except it doesn't do epiglotittis. HiF is a lot more rare, but it does cause epiglotittis. (but not often, because of it's rareness...it doesn't appear to be a good colonizer, I guess).
Most of the increase in "invasive Hi disease" has been with the nontypeable strains. They cause pneumonia and meningitis (and the "lesser" forms of disease not considered "invasive", like ear infections).
What it's looking like to me is that there will always be a dominant colonizer, and the factors that make a bacteria a great colonizer also has the "side effect" of things going too far sometimes, resulting in invasive disease.
For example, in our nose and throat, there's a constant turn-over of cells, and a "good colonizer" has the ability to dig in deep into that tissue to keep from getting shed off .
BUT...while 99.9% of the time that's not a problem, that .1% of the time "being able to dig in deep into the local mucosa" results in bacteremia when everything goes just wrong, which will sometimes turn into meningitis.
Causing invasive disease doesn't benefit the bacteria at all...it's just a side effect of being THE great colonizer.
But any time you remove one dominant species, the selective pressure is on for something else to learn all the same old tricks.
Net benefit to snipering them off one serotype at a time via vaccines = zero.
It's evolution in action and it happens amazingly fast for these little boogers.