May 7, 2026

RSV

RSV-related Impact of Respiratory Syncytial Virus Immunization on the Rate of Pediatric Acute Otitis Media: A Time-series Analysi
Investigators conducted an interrupted time-series analysis based on a French network involving 110 ambulatory pediatricians, trained in pediatric infectious diseases (PARI network). All ambulatory visits for AOM, from June 2017 to February 2025 were included. The main outcome was the monthly rate of pediatric ambulatory visits for AOM in infants aged < 12 months per 1,000 pediatric ambulatory visits over time. They included 70,452 cases of AOM, 13,284 bronchiolitis and 814 UTI. The rate of AOM per 1,000 visits in infants aged < 12 months significantly decreased after RSV immunization implementation (this included passive for the babies with nirsevimab and active for the moms Abrysvo) (−23.7%, 95% CI −37.6 to −9.7, P = .0014), whereas no significant change was observed in older age groups. They observed similar trends for bronchiolitis. The monthly rate of UTI did not significantly decrease.

COVID: The Late Phase/PASC/Long COVID

Multisystem Inflammatory Syndrome in Children (MIS-C), United States, 2023–2024
Multisystem inflammatory syndrome in children (MIS-C) is rare following SARS-CoV-2 infection, but sporadic cases continue to be reported. This analysis of cases from 2023–2024 shows little change in clinical presentation between years. Among vaccine age-eligible children, 99% of cases occurred in children who were not up-to-date with COVID-19 vaccination. There were 141 MIS-C cases with illness onset in 2023 reported by 29 health department jurisdictions, and 82 cases with illness onset in 2024 reported by 24 jurisdictions. Most children had no underlying medical conditions (57% and 59% in 2023 and 2024, respectively). The most frequently involved organ systems were gastrointestinal (89-90%) and mucocutaneous (83-85%). Approximately half (49–55%) of children had cardiac involvement, 29–33% had shock, and 49% required intensive care unit (ICU)-level care. There were four (3%) deaths reported in 2023 among unvaccinated children; no deaths occurred in 2024.

Current Status and Future Perspectives on the Mechanistic and Pathophysiological Understanding of Long COVID
This review synthesises current evidence on the biological mechanisms thought to contribute to Long COVID, spanning immune dysregulation, viral persistence, autonomic dysfunction, microvascular pathology, and other emerging hypotheses. The authors examine advances and limitations in contemporary diagnostic approaches and critically appraise existing treatment strategies, highlighting inconsistencies and gaps that hinder clinical consensus.