why the first attack of the chicken fox gives the total immunity yo the chicken fox?

3 answers

Do you mean chicken pox?

http://www.google.com/search?q=chicken+pox&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
If you mean chicken POX, you'll find your answer in thi site.

http://kidshealth.org/parent/infections/skin/chicken_pox.html
Not always. Once you get the chickenpox, the virus lives in you forever, kept in check by your immune system. Later in life, if your immune system goes haywire, the chickenpox emerges as shingles.

If you get the chickenpox early in life, and have a mild case, the immune response may not be great, and as a result, you can get chickenpox a second time.