Page 80 - AIDSBK23C

Page 80

PEDIATRIC HIV INFECTION AND AIDS

The diagnosis of HIV infection and of AIDS in children under 13 years of age varies
slightly from that in an adult. Significantly, children under the age of 18 months may still retain
passively acquired maternal HIV antibody, while those above 18 months rarely have residual
maternal antibody, so standard immunologic tests alone for HIV infection (EIA and confirmatory
Western blot) cannot be used to define HIV infection in this setting. Both HIV viral culture and
polymerase chain reaction (PCR) assays for HIV RNA or proviral DNA, however, can be used to
detect HIV infection in infants born to HIV-infected mothers with nearly 100% sensitivity by 3
to 6 months of age.[391]
If the mother's HIV-1 status is unknown, then rapid HIV-1 antibody testing of a newborn
can identify possible exposure so that antiretroviral prophylaxis can be initiated within the first
12 hours of life when serologic test results are positive. Those newborns identified with
maternal HIV-1 antibody can undergo testing with HIV-1 DNA or RNA assays within the first
14 days of life, at 1 to 2 months of age, and at 3 to 6 months of age. If any of these test results
are positive, repeat testing is recommended to confirm the diagnosis of HIV-1 infection. A
diagnosis of HIV-1 infection can be made based on 2 positive HIV-1 DNA or RNA assay
results.[395]
In non-breastfeeding children younger than 18 months with no prior positive HIV-1
virologic test results, presumptive exclusion of HIV-1 infection can be based on 2 negative
virologic test results (1 obtained at ≥ 2 weeks and 1 obtained at ≥ 4 weeks of age); 1 negative
virologic test result obtained at ≥ 8 weeks of age; or 1 negative HIV-1 antibody test result
obtained at ≥ 6 months of age. Alternatively, presumptive exclusion of HIV-1 infection can be
based on 1 positive HIV-1 virologic test with at least 2 subsequent negative virologic test results
(at least 1 of which is performed at ≥ 8 weeks of age) or negative HIV-1 antibody test results (at
least 1 of which is performed at ≥ 6 months of age).
Definitive exclusion of HIV-1 infection is based on 2 negative virologic test results, 1
obtained at ≥1 month of age and 1 obtained at ≥ 4 months of age, or 2 negative HIV-1 antibody
test results from separate specimens obtained at ≥ 6 months of age. For both presumptive and
definitive exclusion of infection, the child should have no other laboratory (e.g., no positive
virologic test results) or clinical (e.g., no AIDS-defining conditions) evidence of HIV-1
infection. Confirmation of the absence of HIV-1 infection can be done with a negative HIV-1
antibody assay result at 12 to 18 months of age. For breastfeeding infants, a similar testing
algorithm can be followed, with timing of testing starting from the date of complete cessation of
breastfeeding instead of the date of birth.
The criteria for diagnosis of human immunodeficiency virus (HIV) infection in children
was redefined by the Centers for Disease Control (CDC) in 1994 (establishing new criteria
beyond the 1987 AIDS surveillance case definition[390]) and superseded by the 1997
definition.[393] Classification into mutually exclusive categories is made through assessment of:
a) infection status, b) clinical status, and c) immunologic status. An HIV-infected child cannot
be reclassified from a more severe to a less severe category.
The clinical categories for children with HIV infection are made by the 1994 CDC
definition as follows:[391]