For example, children with Down's syndrome succumb easily to infection of the ears and upper respiratory tract by H. influenzae and S. pneumoniae, and as a result experience considerable antibiotic exposure in their early years. Children with Down's syndrome are known to produce significantly lower levels of IgG2 and IgG4 antibodies than their healthy counterparts. These are precisely the antibodies that are directed against H. influenzae and S. pneumoniae. Anneren et al. A supplements experienced one-half the complications, such as pneumonia, croup, etc., than those on placebo.
Vitamin E has a marked effect on immune function and infection-susceptibility.
Allergy can also have an impact on infectious disease. Nsouli reported on 104 children with chronic otitis media that was unresponsive to antibiotic or surgical treatment. Seventy-eight percent of these children showed reactivity to foods when tested using three methods. A toxic risk score was calculated based on the number and amount of metals present. After three years, the frequency of infections and allergic disorders was assessed for each child.