Concerns over high cases of two common respiratory viruses have doctors encouraging vaccinations and precautionary measures leading into the holiday season. Doctors are blaming high case rates on “immunity debt.”

Doctors say they are seeing an unprecedented number of cases. How concerned should parents be? Why are young children so vulnerable? What's causing this year's outbreak? We offer some answers.

The latest spike is months early and it's pushing care facilities to capacity. Children under the age of 5 are most vulnerable.

Masking over the last two years slowed the spread of respiratory illnesses like influenza and RSV. But now, emergency rooms are filling with pediatric patients. 

Pediatric hospitals are "at or near capacity" and expect to see more young COVID-19 patients as the school year resumes, according to the Children's Hospital Association.

Health care workers on the front lines of the pandemic say there is another concerning prospect looming: a surge in children diagnosed with a combination of COVID-19 and respiratory syncytial virus.