Neonatal CNS Human Parechovirus Infections in Western Pennsylvania in the 2024 Season.

Human Parechovirus A (PeV-A) is a virus with near-universal infection by age five; however, neonatal infections can lead to meningoencephalitis, sepsis, and death. Prior to the COVID-19 pandemic, PeV-A showed biennial seasonality with late summer peaks, but multiple viruses have had shifted circulation post-pandemic. PeV-A is not universally included in neonatal sepsis testing; thus, the frequency and clinical spectrum of PeV-A neonatal meningoencephalitis are not fully described. We sought to evaluate the epidemiology, seasonality, and clinical presentation of neonatal PeV-A in the 2024 season. We collected remnant cerebrospinal fluid samples from febrile infants under 60 days at a single children's hospital in Southwestern Pennsylvania and assessed for PeV-A and enterovirus (EV). Six out of 107 (5.6%) febrile infants were positive for PeV-A and 24 (22.4%) were positive for EV. PeV-A infections occurred from June to September. PeV-A positive patients had a distinct combination of higher maximum temperature, rash, and leukopenia without pleocytosis. None of these infants had severe disease. Systematic surveillance of PeV-A is required to completely understand ongoing PeV-A circulation patterns, expected clinical course, and long-term developmental implications.