An attempt to clear up the confusion about HIV antibodies in newborns.
The easiest test to do for HIV is an ELISA test for the antibody (this is
then confirmed with a second ELISA test and or Western Blot test also for the
antibody). In adults, if your body is making the antibody, you were exposed
to the disease and thus are presumed to have the HIV virus in your blood as
well. However, the tests for the virus are expensive and not very sensitive
(they are known as HIV culture and PCR for fplymerase chain reaction which
is a method that they amplify the minute amount of virus that they find.)
The complicated thing about newborns is that they receive antibodies from MOM
via the placenta. Thus if baby has a positive test for the antibody it means
that mom is infected with the HIV virus and has made antibodies. Almost 100%
of babies born to HIV+ mothers will have positive antibody tests (principle
in Medicine - never say never). However, only about 1/3 of this infants
really contracted the virus.
  Babies loose maternal antibodies in the first 18-24 months. Thus if a baby
becomes negative ("seroreverts) it is felt that the baby got the antiboides
from mom but not the virus. If baby continues to have antibodies in after 2
years it is felt that the baby is starting to makes his/her own and truly is
HIV infected. The reasons some babies become negative and then later become
positive (shich does ocassionally happen is due in part because no test is
100% foolproof (false negative, false positives etc) Hope this helps

--
****************************************************
*  Deena Zimmerman MD MPH                          *
*  Department of Pediatrics                        *
*  UMDNJ-Robert Wood Johnson Medical School        *
*  1 RWJ Place                                     *
*  New Brunswick, NJ 08903                         *
*                                                  *
*      phone (908) 235-7248                        *
*      fax   (908) 235-7345                        *
*      email  [log in to unmask] (internet)        *
****************************************************