Some important factors
In the child include age, immunity, nutrition, genetic makeup and overall health. Newborns are at risk because their protection systems have not yet been tested and are not always mature. Babies are at risk because they have a tendency to put everything in their mouths and rarely wash their hands. Older children have fewer risks because their hygiene is better and they have become immune through previous infections or the transport of bacteria.
Health: Another important factor for a child is the use of medical devices such as catheters (tubes placed in the blood vessels or in the bladder) and other tubes (for example, from the nose to the stomach, from the nose to the lungs). These catheters and tubes provide a direct route for bacteria and fungi to enter the blood, bladder or lungs. Medicines such as corticosteroids (used for asthma and many other conditions) and chemotherapy for cancer can interfere with a child’s ability to fight an infection. Even antibacterials can be a factor in killing the normal protective flora.
Health: Factors in bacteria, viruses and fungi include genes that determine how harmful (virulent) the microbe can be. Some germs create toxins that cause diseases on their own or contribute to infections caused by the germ. Examples include enterotoxins, which cause diarrhea; tetanus toxins, which cause tetanus; and toxic shock toxins, which causes low blood pressure and collapses (shock).