By Adam Cancryn, David Lim and Chelsea Cirruzzo

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.

The additional doses come amid shortages that have left parents and providers scrambling for shots.