LONDON — Concerns are growing over a new variant of the coronavirus blamed for a sharp rise in cases in the UK. br br The new strain, referred to as B.1.1.7 or VUI-20201201, contains 23 mutations and other changes to its genome, according to a Reuters report. br br BBC News reports officials in the UK have suggested that the new strain may be 70 percent more transmissible than other forms of the virus.