Three new variants of Covid-19 have been causing concern in recent times. One that originated in the UK, another that originated in South Africa and more recently a variant that has originated in Brazil.
But what are variants and should we be worried about them? Are there just three variants? No, there have been many variants of the virus since it first emerged from Wuhan in China just over a year ago.
By their very nature, viruses evolve, so scientists are not surprised by these changes. Some have come and gone, such as the Danish variant that was discovered in minks that was eliminated when authorities in Denmark culled the mink population there.