How are experts tracking variants of the coronavirus?

Scientists are tracking variants of the coronavirus by scanning virus samples taken from infected people. The process is called genome sequencing and lets experts look for recurring changes in the genetic code of the virus over time. Most mutations are meaningless, but scientists are looking for those that might make the virus more infectious or resistant to vaccines. Countries vary in their genomic surveillance. Britain, for example, sequences about 10% of samples from infected people, compared to less than 1% in the U.S.  So far, scientists have sequenced nearly half a million genomes of the coronavirus, and are primarily concerned about three variants.