NEW YORK (Reuters Health) – A significant percentage of infants born to HIV-infected mothers still have maternal HIV antibodies well beyond 18 months of age, which is the cutoff for the surveillance case definition for HIV infection currently used by the Centers for Disease Control and Prevention (CDC).
This means that HIV antibody tests should not be used to diagnose HIV infection before age two, according to Dr. Mavel Gutierrez from Florida’s University of Miami-Miller School of Medicine.
“Given the finding of delayed clearance of HIV antibodies in perinatally HIV exposed infants, the main concern is that persistence of HIV antibodies after 18 months of age may cause confusion among pediatricians causing children to be misclassified as HIV infected when they are not,” Dr. Gutierrez told Reuters Health by email.
Dr. Gutierrez and colleagues describe the timing of seroreversion among 744 HIV-exposed uninfected infants born since 2000, as documented by enzyme-linked immunosorbent assay (ELISA).
In just over a third of the infants (273, 36.7%) included in the July 31 Clinical Infectious Diseases online report, antibody loss had occurred by their first ELISA test. The median age of seroreversion was 13.9 months.
A quarter of the infants seroreverted by 12 months, and 75% seroreverted by 16.4 months. More than 1 in 7 infants (14%) remained seropositive after 18 months, 4.3% after 21 months, and 1.2% after 24 months without other evidence of HIV infection.
The higher the IgG values and the higher the IgG rate of change, the earlier the clearance of antibodies took place. Other factors significantly associated with earlier seroreversion were birth by vaginal delivery, lower maternal viral load, and lower maternal CD4 count before delivery.
Maternal exposure to protease inhibitors was associated with later seroreversion.
“Further studies are needed to evaluate why these factors influence time to seroreversion,” Dr. Gutierrez said.
“None of these children were infected with HIV,” Dr. Gutierrez said. “However, in the case of persistence of antibodies after 18 months of age, the child should be evaluated for other modes of transmission of HIV and retested using virologic tests such as HIV DNA PCR or HIV RNA PCR assays.”
“Non-perinatal HIV transmission, although rare, in the first two years of life include premastication of food for the infant by an HIV infected person, sexual abuse, or exposure to contaminated needles,” Dr. Gutierrez added.
Clin Infect Dis 2012.