OBJECTIVES When you have completed this unit you should be able to: List the routes whereby infants can be infected with HIV. Diagnose HIV infection in infants. Use antiretroviral drugs prophylactically in newborn infants Explain the risk of breast feeding in HIV positive mothers. Advise HIV positive mothers on the choice of feeding methods. List ways of making milk formula available to more HIV positive mothers. Explain the dangers of making cheap milk formula available to all mothers. Manage infants born to HIV positive women.

COPYRIGHT

All rights reserved. No part of this Perinatal Education Programme may be altered in any way without the written permission of the editorial board of the Perinatal Education Trust. To facilitate the improvement of perinatal care, the Programme may be reproduced for teaching purposes provided due acknowledgement is given and the material is not sold for financial profit. While the advice and information in the Programme is believed to be accurate, the editorial board cannot accept responsibility or liability for any errors or omissions that may have been made.

ISBN 0 7992 1955-X

34-1 CAN NEWBORN INFANTS BECOME INFECTED WITH HIV?

Yes. Newborn infants may become infected with HIV:

1. During pregnancy when HIV may cross the placenta from a mother to infect her fetus.
2. During labour and delivery when the infant may become infected with HIV present in cervical and vaginal secretions, and maternal blood.
3. After delivery when the infant may become infected with HIV present in breast milk.

*** Rarely the infant may become infected with HIV in transfused blood or by HIV contaminated needles.

BOTH THE FETUS AND NEWBORN INFANT CAN BECOME INFECTED WITH HIV

Infants cannot become infected by touching, hugging or kissing them.

The spread of HIV from a mother to her fetus or infant is called mother-to-child transmission (MTCT) or vertical transmission. Nearly all infants and young children with HIV infection have been infected by vertical transmission.

34-2 DO HIV INFECTED INFANTS USUALLY APPEAR NORMAL AT BIRTH?

Most infants that have been infected with HIV during pregnancy, labour or delivery appear normal at birth. It is, therefore, not possible to decide by physical examination alone whether or not a newborn infant is infected with HIV.

MOST INFANTS WITH HIV INFECTION APPEAR NORMAL AND HEALTHY AT BIRTH

*** A few infants that have been infected early in pregnancy may have clinical signs of AIDS at birth.

34-3 DOES HIV INFECTION CAUSE CONGENITAL ABNORMALITIES?

HIV infection of the fetus does not cause congenital malformations. However, HIV infected infants have an increased risk of having a low birth weight.

34-4 SHOULD ALL INFANTS BORN TO HIV POSITIVE MOTHERS BE SUCTIONED AT DELIVERY?

Unless there is meconium stained amniotic fluid or the infant needs resuscitation, the infant must not have the mouth and nose routinely suctioned after birth as this may damage the mucous membranes and, thereby, increase the risk of HIV infection. Routine suctioning should be avoided in all infants.

34-5 CAN THE HIV SCREENING TEST, COMMONLY USED IN ADULTS, ALSO BE USED TO DETECT HIV INFECTION IN A NEWBORN INFANT?

The diagnosis of HIV infection in a newborn infant is difficult as most HIV infected infants appear to be normal and healthy at delivery. The HIV antibodies, tested for in the ELISA and rapid HIV screening tests, cross the placenta from mother to fetus as they are small proteins (IgG antibodies). Therefore, if the mother's HIV screening test is positive then the infant's test will also be positive, whether or not the infant is infected with HIV. All infants born to HIV positive women will have a positive HIV screening test at delivery. As a result, the HIV screening tests for adults is not useful in infants during the first months of life.

A POSITIVE HIV SCREENING TEST IN THE NEWBORN INFANT DOES NOT NECESSARILY MEAN THAT THE INFANT IS INFECTED WITH HIV

34-6 WHEN CAN THE HIV SCREENING TEST BE USED TO DIAGNOSE HIV INFECTION IN HIV EXPOSED INFANTS?

By 18 months after delivery all maternal HIV antibodies will have disappeared from the infant. A positive screening test after 18 months indicates that the HIV antibodies are being produced by the infant and have not crossed from the mother during pregnancy. Therefore, a positive screening test for HIV in an infant of 18 months or older indicates that the infant is infected with HIV. This is a convenient time to screen these infants as they are attending a clinic for their booster immunizations.

The maternal HIV antibodies will already have disappeared by 9 months in about 50% of uninfected infants. Therefore, it has been suggested that infants born to HIV positive women should be screened at 9 months when they attend clinic for their measles immunization. A negative test will indicate that the infant is not infected, provided that the mother has not breastfed in the past 2 months. A positive test at 9 months should be repeated at 18 months as all uninfected infants will have become negative by then.

34-7 WHAT BLOOD TESTS CAN BE USED TO DIAGNOSE HIV INFECTION IN A YOUNG INFANT?

HIV infection in infants younger than 18 months can be diagnosed by either of the following:

1. The most accurate blood test is the PCR (DNA polymerase chain reaction) which detects the presence of genetic material from the HIV. If the PCR test is positive then the infant is infected with HIV. Unfortunately the PCR test is expensive and is not available in small hospitals.
2. The p24 antigen test detects HIV protein in the blood. It is not expensive. A positive p24 antigen test indicates that the infant is infected with HIV. Unfortunately the test is often negative in HIV infected infants.

A negative PCR or p24 antigen test does not always exclude HIV infection as both tests may take a few weeks to become positive after the time of infection. However, the PCR usually become positive by 6 weeks after HIV infection.

*** HIV may also be cultured from the blood of infected infants. However, this is expensive and requires great expertise. As a result, this test is not often used.

34-8 CAN THE PCR TEST BE USED TO IDENTIFY WHEN AN INFANT BECAME INFECTED WITH HIV?

Yes, it is helpful in identifying the time of infection. If the fetus is infected in early pregnancy then the PCR on the infant's blood will be positive at birth. However, if the infant only becomes infected in the last weeks of pregnancy, during labour and delivery or during the first week of life then the PCR may only become positive by 2 months of age. The test may only become positive more than 2 months after delivery in infants who are infected with HIV via breast milk.

*** A negative test at delivery does not, therefore, exclude HIV infection, which has taken place late in pregnancy or before delivery. While a negative test at 2 months should exclude infection in a strictly formula fed infant, this is not true in an infant receiving breast milk. The PCR may still become positive up to 2 months after an HIV positive woman stops breast feeding.

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