In early April, when word began to circulate that hospitals in the United Kingdom were seeing unexplained hepatitis cases in very young children, some physicians and researchers on this side of the Atlantic experienced a moment of déjà vu.
Kevin Messacar and colleagues at Children’s Hospital Colorado found themselves remarking on how reminiscent the unfolding investigation was of a medical mystery they’ve been enmeshed in for the past eight years — acute flaccid myelitis, or AFM, a polio-like condition in children.