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Re: HIV/AIDS question [HAPP-L]

John Moore wrote:

> To the clinical & Micro folks on the list:
> One of our PT folks passed on these excellent questions from the HS section of our A&P students:
> 1)  Is C-section delivery safer than vaginal when the mother is HIV - pos?  If so - why?

Yes - C-section delivery avoids passage through the vagina, where the viral load is higher (in contaminated vaginal secretions, from maternal bleeding as blood vessels are torn during the "activity" of delivery).

> 2) Can the virus travel transplacentally from mother to infant?

Yes - this is thought to be the major way infants are infected.

> 3)  Are the HIV antibodies of the class that can cross the placenta?  IF tested based on antibodies, could a newborn test positive, only to show negative after passively acquired Abs degrade?  (Aren't most tests nowadays based on the virus itself, as opposed to the Ab?)

Yes - they are IgG immunoglobins.  A positive HIV Ab test on a newborn must be repeated 4 to 8 weeks after the birth in order to confirm that the baby is producing an immune response to the virus and isn't still carrying mom's Abs acquired passively.

Most tests are still based on detecting the Ab to HIV because they are quicker and cheaper - and sometimes the Ab is all you detect if the viral load is extremely small and is in "hiding".  But antigen testing is the confirmatory test for a positive Ab test result.

> 4)  Can the various antiviral cocktails (e.g., AZT and the newer meds) be given during pregnancy?

They are given if the mom tests HIV positive and side effects be damned.  The idea is to lower mom's viral load during the pregnancy so as to lower the chance of transmission to the fetus.  And it does work, although not always.  I've read quotes of anywhere from 50 - 90%
reduction in transmission of HIV during pregnancy if mom is put on AZT+ as soon as she tests positive.  Of course, the estimate of transmission without any antiviral treatment runs about 30 -50% (depends on whose study you read) - but that means that probably more than half
of HIV infected mothers aren't going to pass the virus on anyway, even without treatment.......but, if given the choice to raise those odds, wouldn't you?
Tina Ziemba, Ph.D.,MT(ASCP)SM
Dept of Biological Sciences
5047 Gullen Mall
Wayne State University, Detroit, MI  48202

(313) 577-0132   FAX: (313) 577-6891

Microbiology Section Leader
Detroit BioMedical Laboratories, Inc.
Farmington Hills, MI   USA