We have an adopted child whose birth mother was in an extremely high risk catagory for HIV. We know she had a history of prostitution and IV drug use. The baby tested positive for hepatitis a,b,& c but has since cleared those antibodies and is now hepatitis negative. At 4 months he was also tested for HIV and was negative at that time. Can he sero convert if his mother was positive or would he have had the antibodies from birth and tested positive at 4 months? Should he be retested at a later date?

Most antibodies in babies' blood at birth are passed to them from their mothers over the last trimester of pregnancy. Therefore, antibodies alone can not be used to determine the HIV, hepatitis B, or hepatitis C infection status of a baby and more specific methods (PCR, which detects viral genomes) must be used. We only use these more sensitive methods when antibody testing suggests that the mother is antibody positive and therefore infected with the virus. If your baby's mother was HIV-infected, she should have had antibodies to HIV, which she would have passed on to the baby. These antibodies should still have been detectable at 4 months of age. With a negative antibody test at 4 months, it is unlikely that your child is at risk for HIV infection and repeated testing is not necessary.