In the revised manuscript, this information was added. “This database is available to outside researchers after obtaining approval from the CDC and KP. Information regarding access to this database is at: http://www.cdc.gov/vaccinesafety/ensuringsafety/monitoring/vsd/accessing-data.html.”
In table 1, the "-" is used to signify absent values but that should be footnoted in the table precisely what this signifies.