Despite recent talk that there may be Canadian children who have been functionally cured of HIV just as the famed “Mississippi baby” was, proof of such a feat has not yet materialized, and one of a handful of potential children experienced viral rebound after a recent treatment interruption, MedPage Today reports. At the annual meeting of the Canadian Association for HIV Research, clinicians reported about five children across the country who were all treated with aggressive antiretroviral (ARV) regimens shortly after birth and who afterward showed little or no sign of the virus even under highly sensitive tests.

The clinicians for one of the children, who is now 3 years old, decided to take the child off ARVs at least temporarily because the toddler’s caregiver was not properly adhering to the schedule for administering the ARVs. Before the treatment interruption, the child had undetectable proviral DNA and evidence of cell-associated RNA, although the researchers could not isolate any virus from the child that proved able to replicate. Within two weeks of the treatment interruption, the child’s viral load shot up to 7,797, and after another two weeks to 11,358.

The researchers theorize that one possibility is that, because the child’s mother had resistance to the non-nucleoside reverse transcriptase inhibitor class of ARVs, and because the child was given the NNRTI Viramune (nevirapine) until a switch was made 25 days after birth, a window may have been created that allowed time for the virus to establish a reservoir.

The remaining four children are between 3 and 8 years old and are all on ARVs. Ethical considerations make it difficult to opt to interrupt their treatment, although the potential benefit of helping the children escape side effects from lifetime treatment may weigh in the favor of exploring this option.

To read the MedPage Today story, click here.