Detection of virus in vertically exposed HIV-antibody-negative children.

BACKGROUND: HIV-infected mothers can transmit their infection to their children in utero or at delivery (vertical transmission). There have been cases of children who were reported as acquiring infection vertically and later clearing the infection. We report the frequency of this phenomenon in a European cohort study.
METHODS: In four centres of the European Collaborative Study of children born to HIV-infected mothers, 299 children became HIV-antibody-negative and 264 of these had been followed up with virus culture and PCR for viral DNA at least once.
FINDINGS: Nine of the 264 children were positive by virus culture or PCR, and subsequently seroreverted. Two of the nine tested virus-positive after they became antibody-negative. Six cases were virus-positive early in life and became negative thereafter, which is consistent with clearance of infection. The pattern was less clear in the other three. The nine cases had had their last virus test at age 16-101 months. All nine children had been bottlefed only. Eight had been delivered vaginally. The children had no HIV-related symptoms and received no anti-HIV treatments. Based on only those children who had two or more positive virological tests, we estimate that 2.7% (6/219) cleared or "tolerated" the virus.
INTERPRETATION: The detection of virus or viral DNA in "uninfected" children born to HIV-infected mothers was rare and was not associated with clinical disease or immunological abnormalities. The timing of samples will affect the documentation of clearance since, in uninfected children of HIV-positive mothers who cleared the virus, viraemia was intermittent. Current paediatric opinion is to inform parents of children who serorevert that the child is not HIV-infected.