So why do I get some illnesses lots of times?

National electronic Library of Infection

Bugs & Drugs on the Web
NeLI Antimicrobial Resistance Website

Learn about Resistance
Antimicrobial Resistance & Common Illnesses Preventing Antimicrobial Resistance Other Resources

Current Location: Home > Learn > Immune System > So why do I get some illnesses lots of times?


Scientists make immunity breakthrough


Resources about the Immune system and disorders

More resources...

Current Tip

Finish your course of antibiotics
More Tips...


Give us your feedback about this website

So why do I get some illnesses lots of times?

We seem to get some infections, like colds, year in and year out. If our immune system remembers the invading germ and quickly gets rid of it why do we keep getting colds? This is because the antigens that our immune system recognises and the antibodies that our body produces are very specific. Think of a padlock and key. Although many padlocks look the same, and many keys look the same, only one specific key will fit one specific padlock. If the padlock changes at all, even slightly, the key will not fit. Now imagine that the antigen (on the germ) is the padlock and the antibody (from the immune system) is the key. Some germs are good at changing their antigens (or padlock) so that when they infect us a second time our immune system does not recognise the padlock (or antigen) that the germ is carrying. That is why when we have one cold we are not protected against getting another, because the virus that causes a cold will probably have changed its antigen by the next time we are infected. This is also why the HIV virus is so difficult to treat. The antigens on HIV change so rapidly that the immune system is not able to act quickly enough to get rid of it from the body. (See the HIV section for more details).

Related Resources
How your immune system works
The Complete Idiot's Guide to Dangerous Diseases & Epidemics
Resources about the Immune system and disorders

Date of Posting: 10/01/2003
Date of next Review: 15/01/2005

Related Questions:
How does my body protect itself against infection?
What happens if the microbes get through the first defences (the innate response)?
What is the adaptive immune response?
Why do I only get some illnesses once?
Why may I need to take antimicrobials?

MeSH keywords:
Immune System; Immunity; Immunity, Natural; Immunity, Active; Immunity, Cellular; Antigens; Antibiodies

Created by CeRC. Page last updated 15/1/2004. To contact us click here.

Free DHTML scripts provided by
Dynamic Drive

City University City UniversityNational Electronic Library for Health (NeLH)

National Library for Health (NLH)
NHS Direct 0845 4647 NHS Direct 0845 4647 Health Protection Agency Health Protection Agency