Parainfluenza Virus Is Surging Nationally Right Now, and Parents Need to Know the Signs of Croup Before It Becomes a Breathing Emergency

CDC respiratory surveillance updated June 12, 2026 confirms parainfluenza virus (PIV) is elevated nationally. PIV is the leading cause of croup in young children. Summer camp and daycare season is peak exposure time. Here is what parents need to recognize — and when to go to the ER.