The UK announced in December that a more transmissible variant of COVID-19 was spreading in the country, prompting stricter lockdown measures and travel restrictions.
Since then, several other variants have emerged in different parts of the world.
Viruses often change as they make copies of themselves and these changes are called mutations. The World Health Organization (WHO) defines a variant as a virus that has one or several new mutations .
Changes in the coronavirus are not unusual: viruses have more opportunities to mutate as they infect more people but experts have said that SARS-CoV-2 has been slower to change.
Here’s what we know about the coronavirus variants in Britain, South Africa, Brazil and California.
Scientists discover five genes that put you most at risk of severe Covid thesun.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from thesun.co.uk Daily Mail and Mail on Sunday newspapers.
Covid gene breakthrough could lead to new treatments
The discovery helps explain why some people are more susceptible to the disease
Five gene variants which increase the risk of individuals becoming seriously ill from coronavirus have been discovered by scientists, in a breakthrough which could lead to new lifesaving treatments.
The discovery helps explain why some people are more susceptible to the disease and may hint at why some families and ethnic groups are disproportionately impacted.
Researchers from the University of Edinburgh made the discovery by studying the DNA of 2,700 Covid-19 patients in 208 intensive care units (ICUs) in the UK.