[abap_rocky]

When my then 4 month-old was hospitalized with RSV last year, the medical staff told us the main issue with RSV in very young children (under 6 months) is that their respiratory system is still immature. That is, their airways are still very small and their coughs are less productive. This means that RSV symptoms that would be manageable for an older child can become potentially life threatening for the very young.

For example, if your toddler has a stuffy nose, you can help them to blow it. For an infant, you need a tool to suction their nose which can be difficult to do. That same stuffy nose might cause poor feeding and dehydration which on top of the general breathing issues caused by RSV can lead to a rapid deterioration in the infant's health.

Even with all the supportive care (oxygen, regular suctioning, a feeding tube), it took a full 5 days in the hospital for our infant to recover.

My first-hand experience with this seems to be consistent with larger trends as well. A recent CDC presentation shows that children age 0-5 months are hospitalized by RSV at far higher rates than any other age group. [1]

[1]: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-...