
When kids stayed in the home until kindergarden or 1st grade, infection 
incidence was much lower because exposure was lower.  Some studies suggest 
that early exposure to various infectious diseases is probably beneficial 
because exposure as an adult carries much more risk of morbitity and 
mortality(mumps, measles. etc.).


Daycare will always carry a higher exposure risk than home care.


Exposure to infectious organisms does build immunity.  But many viruses 
mutate and reexposure to the new strain requires another immune response(
new antibody production).  In addition, antibody levels tend to decline 
with time and re-innoculation is needed to keep the antibody levels high.
Chronic overstimulation of the immune response can lead to immunosupression 
but this is rare and very unlikely to occur in children.


Yes, chronic use of antibiotics can have an adverse effect on the good 
bacteria that are supposed to be present in and on the body.  Health effects 
of this depletion of the good bacteria is a very hotly debated topic in the 
medical community with most physicians seeming to discount any health effects 
of chronic antibiotic use( a view that I do not support).
 

Chronic infection in an adult or a child needs to be worked up( in my 
opinion).  But most physicians feel that chronic infection in a child is 
normal because of both exposure and lack of prior immunity to many 
infectious diseases.  I do not share this view and there are some 
physicians who also suspect that diet plays a big role in infection 
frequency and severity.  Exposure to an infectious agent does not have to 
result in a severe infection.  A strong immune response can minimize the 
length of time needed to deal with the infection as well as the symptoms 
associated with the infection.


There are five major nutrients that are responsible for a good strong 
immune response to infectious agents.  They are: protein, vitamin C, 
vitamin A, iron and zinc.  The American diet is not low in protein so this 
is rarely a problem.  But vitamin A, vitamin C, iron and zinc are often low 
and this lack of an adequate pool(nutrient reserve) can impair the immune 
response.  Iron is know to be low in most kids(as is vitamin A).  There are 
distinct biochemical tests that can be run to check the status of each of 
these nutrients in a patient who is having a problem with chronic severe 
infection.  Serum ferritin for iron status, dark adaptation for vitamin A 
status, red blood cell zinc for zinc status and leckocyte ascorbate for 
vitamin C status.  I have attempted to work up posts on these five 
nutrients and their role in infection for this news group as well as the 
others that I participate in.  I can e-mail you what I've worked up so far.
But my best advice to you is to try to find a physician who recognizes the 
critical role that diet plays in the human immune response.  You may also 
be able to get help from a nutritionist.  Anyone can call themselves a 
nutritionist so you have to be very carefull.  You want to find someone(
like myself) who has had some formal training and education in nutrition.
Many Ph.D. programs in the U.S. now offer degrees in Nutrition and that's 
what you need to look for.  Some dieticians will also call themselves 
nutritionists but most dieticians have not had the biochemical training 
needed to run specialized nutritional assessment tests.  They are very good 
for getting general dietary advice from however.
