Only one other state — Florida — has more cases of the so-called United Kingdom (U.K.) variant than Michigan, according to the CDC. Variants are concerning to public health officials because they appear to spread more rapidly than the original virus that produced the pandemic. There’s also emerging research that suggests that the U.K. variant may be more deadly. The COVID vaccines now authorized for emergency use in the U.S. appear generally effective against the variants, but to what extent is still not clear. Michigan also confirmed this month its first case of the B.1.3.5. variant, what has also been called the South African variant.