Tracking COVID-19 Variants Act This bill expands viral genomic sequencing, disease surveillance, and other public health research activities. Specifically, the Centers for Disease Control and Prevention (CDC) must issue guidance on the sequencing of the virus that causes COVID-19 (i.e., coronavirus disease 2019). Additionally, the CDC must establish a program to strengthen genomic sequencing, analytics, and disease surveillance activities. As part of this program, the CDC must provide grants and technical assistance to health departments to build their capacity to carry out such activities. Furthermore, the National Center for Health Statistics (NCHS) must carry out a demonstration program to expand an existing program that links different federal data sets for statistical public health research, including research on food insecurity, housing instability, and other social determinants of health. In particular, the program must support linkages with the National Death Index, a database of death records maintained by the NCHS.