Vaccines and Immune Deficiencies

AM Rodriguez arodri03 at
Thu Nov 2 13:09:43 EST 1995

  Today my doctors would not let me get any live vaccine.  Why?  I still don't 
>  understand the difference between live and inactive vaccines and their
>  effect in the immune system.
Hi, Sonia:

I am an Immunologist. About your question on the difference between live and inactivated vaccines.
Inactivated vaccines are made of virus or bacteria (depending on the disease) that are dead. Sometimes the vaccine only 
contains part of the dead virus or bacteria, not the whole thing. That means that since the virus or bacteria is dead it won't 
reproduce in your body, and therefore it won't make you sick with the disease they cause. Although the pathogen is dead, if the 
vaccine is good, the immune system would respond producing antibodies or specialized cells that will fight the disease. In your 
case the antibody response is very low or undetectable. I don't know if any cellular response to the vaccines has been done in 
your case. 
 On the  other hand, live vaccines contain live virus or bacteria,  not fully virulent, but potentially able to cause the disease in the 
patient. Your immune system is not producing the antibodies that would protect you against the disease, so it is not safe for you 
to receive any vaccine that contains a live pathogenic virus or baceria.

Hope this clears the picture.
Ana Maria Soler-Rodriguez
arodri03 at

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