Why do people only get some diseases, like chicken pox, once?

For many diseases, if you catch them once, you will never catch them again. Measles is a good example, as is chicken pox.

When these diseases make it into your body, they start reproducing. As this happens, the immune system gears up to eliminate the disease. In your body you already have B cells that recognize a virus and produce antibodies for it. But there are only a few B cells for each antibody. Once these few B cells recognize a particular disease, the B cells turn into plasma cells. They clone themselves and start pumping out antibodies. This takes time, but the disease runs it course. Eventually, the disease is eliminated.

While it is being eliminated, however, more B cells that recognize the disease clone themselves but do not generate antibodies. This set of B cells can remain in your body for years. Therefore, if the disease reappears, your body is able to get rid of it before it can do anything to you.

This is how vaccines work. A vaccine is a weakened form of a disease (either a killed form of the disease, or a similar but less virulent strain). Once the vaccine is inside your body your immune system mounts its defense, but because the disease is different or weaker the body shows no symptoms of the disease. When the real disease invades your body, the immune system is able to eliminate it immediately. Vaccines have been made to combat all sorts of diseases, both viral and bacterial.

Continue Learning about Chicken Pox

Could I have chickenpox and not even know it?
Honor Society of Nursing (STTI)Honor Society of Nursing (STTI)
Yes, you could have chickenpox and not show signs of it. This is because the rash doesn't show up fo...
More Answers
Will a bath spread a chickenpox rash?
Honor Society of Nursing (STTI)Honor Society of Nursing (STTI)
Don't worry. Baths will not spread the rash you have from chickenpox from one part of the body to an...
More Answers
Is chickenpox serious?
Honor Society of Nursing (STTI)Honor Society of Nursing (STTI)
When chickenpox infects a normally healthy child, it usually will clear up without special treat...
More Answers
Can my child go to school if he or she has chickenpox?
Dr. Mehmet Oz, MDDr. Mehmet Oz, MD
Chickenpox is very contagious. It can be spread by blister contact or through the air. Most schools ...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.