aligning before versus after

Source

This excellent visualization of vaccine effectiveness made the rounds over the past few days:

Five plots of historical disease occurrence, with the date of vaccine introduction aligned vertically. Each disease is essentially eliminated by its vaccine.

Hat tip. The plots are from a 2015 piece in the Wall Street Journal, but apparently the stitching together was done by Edward Tufte.

Each block of data is disease occurrence over time for the fifty US States, with warmer colors representing more cases. The horizontal scale is "years from introduction of a vaccine," with the black line at $t=0$. I think that mumps and rubella were so common that there just aren't any data from before the vaccines were introduced, although the cynical reaction was "vaccines cause mumps."