design: A negative control library was made side-by-side with the processing of the second ampule of vaccine using nucleotide-free dH2O as input.  Identical procedures were followed for Whole Genome Amplification (WGA) with the REPLI-g Advanced DNA Single Cell Kit (Qiagen, Germantown, MD), library construction with the ThruPLEX DNA-Seq Kit (Takara Bio USA, San Jose, CA), and sequencing on the Illumina MiSeq.