What Is Immunity and How Do We Develop It?

Artistic representation of immunity.. Sebastian Kaulitzki/Science Photo Library/Getty Images

Immunity is a term used frequently in the medical field. Our immune systems protect us from illnesses. If we are immune to an illness, it means we won't get sick if we are exposed to the germs that cause it. When you have an immunity to something, it means that your body can fight that disease or infection without making you sick. People with compromised immune systems have more difficulty with this and are at greater risk for serious illness.


What Happens Inside Your Body

When you get sick, your body is fighting off a disease and you experience symptoms depending on what that illness is. You have a lot of different types of cells inside your body that do different things to keep you healthy. Leukocytes are one type of cell that makes up your immune system. You have probably heard them called white blood cells (WBC's). They travel through the body looking for disease causing germs and destroy them. There are other cells that help the immune system as well. Complement is a type of protein that assists in killing bacteria, viruses and other infected cells. Your lymph nodes, thymus, spleen and bone marrow all play a part in protecting you from illness too.

When an antigen (a germ that can make you sick) enters the body, your immune system is triggered and it creates antibodies. Antibodies are a special kind of protein that attaches to the antigen and remember it.

Other cells in the immune system then come destroy the antigen. The antibodies remain in your body so it will recognize the germs if you are exposed to them again.  

How We Develop Immunity

Being immune to a disease means that your body is able to kill the germs without experiencing any symptoms. We develop immunity in several ways.

Natural exposure - such as getting sick with an illness - is one way. Once you get some illnesses, you immune system develops antibodies to that illness and it protects you from getting it again. This doesn't occur with all illnesses, but it does occur with a lot of them. 

We also get immunity from vaccines. Being vaccinated against a disease allows our bodies to develop antibodies to that illness without actually getting sick. When you get a vaccine, your body "sees" the disease and learns how to fight it but you don't experience the symptoms that you would if you actually got sick. 

Babies also have some immunity passed on to them from their mothers at birth. Generally these antibodies are gone after about 6 months, but there is some protection during the first few months of life. Breastfeeding increases this protection. This is also why babies can get some protection against serious illnesses like the flu and pertussis if their mothers are vaccinated during pregnancy. The protection from those vaccines are passed on to the baby as well.



"Immune System". KidsHealth For Parents. May 2015. The Nemours Foundation. 28 Feb 16. 

"Immune Response". MedlinePlus. 11 May 14. US National Library of Medicine. Department of Health and Human Services. National Institutes of Health. 28 Feb 16. 

Continue Reading