Since coronavirus was first identified a year ago, thousands of mutations of the deadly bug have appeared all over the world causing it to spread between people even faster.
All virus make tiny genetic changes so it can make new copies of itself to survive, with research suggesting Covid-19 mutates every two weeks.
While the vast majority of mutations have little impact, every once in a while a variant can become threatening and be more infectious to humans.
Scientists from the Government’s Scientific Advisory Group for Emergencies have now warned the UK may see more variants than other countries because more people here already have some immunity, The Mirror reports.
It comes as all overseas passengers arriving in Scotland must now self-isolate for ten days after quarantine ‘travel corridors’ were axed.
Scotland could now face tighter border restrictions beyond the scrapping of quarantine-free international travel amid months of months of warnings they were allowing unchecked spreading of deadly Covid-19.
So what are the current variants that have been identified around the world and how worried should we be?
UK
A UK variant cropped up in the UK in late 2020, going from non-existent to spreading to more than 50 other countries in just a few weeks.
The rapid spread of a new variant of the mutation has been blamed for the introduction of strict lockdown rules on mixing at Christmas in Scotland and other UK countries with strict travel bans.
The variant - officially known at VUI-202012/01 or lineage B117 - was first detected in the parts of the south-east of England in September.
It now accounts for more than 60% of positive Covid-19 tests in England and 40% in Scotland, according to the UK's Office for National Statistics.
However, it is not thought to be more deadly or cause more severe illness.
It is thought the variant either emerged in a patient in the UK or has been imported from a country with a lower ability to monitor coronavirus mutations.
The variant can be found across the UK, except Northern Ireland, but it is heavily concentrated in London, the South East and eastern England.
South Africa
Scientists around the world have been alarmed by the rapid spread of the new 501.v2 variant first detected in South Africa, and the equally infectious B.1.1.7 variant that has led to a recent surge in cases in the UK.
It's different to the mutation discovered in the UK - and scientists have raised concerns about its effect on the vaccine.
Both the new and UK variants appear to be more contagious, and it is already the dominant virus in the Eastern and Western Cape provinces of South Africa.
Other countries including Austria, Norway and Japan have also found cases.
Brazil
Now, a new strain is causing concern, detected in four Japanese travellers who had recently returned from Brazil’s Amazonas state.
While not yet classified as a new variant, Brazilian scientists believe the mutation emerged in the region, which is currently experiencing a surge in cases.
The more changes to its genetic code a variant has the more differently it can behave. Both the UK and South African variants, which each carry around 20 mutations, are both about 50% more contagious than previous forms of the virus.
The new variant from Brazil has 12 mutations. While the virus is still being analysed, scientists believe it is also linked to increased transmission, with two mutations on the spike protein which are similar to the UK and South African versions.
Felipe Naveco, from Brazil’s Fiocruz scientific research centre, said: “It’s a virus that has gone through a process of evolution, which makes us think that maybe it’s a new Brazilian variant.
"These mutations are very worrying, and we need more time and analysis to really know how it might increase transmission.”
Brazil’s vast jungle state of Amazonas has seen an explosion of cases in recent weeks, with more people admitted to hospital in the first week of 2021 than the whole month of December.
Brazilian researchers reported that a woman had been infected twice with the South African variant in what is believed to be the first such case in the world. The woman, from the Brazilian city of Salvador, reported more powerful symptoms the second time around.
With the health system on the verge of collapse, refrigerator trucks were deployed this week to store bodies after space ran out in hospitals.
While there is no proof so far that the new variants cause more severe disease, worrying evidence emerged this week that the South African variant may be able to evade immunity from prior infections or vaccines.
Disease experts have warned that we should expect more highly contagious new variants of coronavirus to emerge more frequently, especially as the virus tries to evade global immunisation efforts.
Prof Abdool Karim, the epidemiologist who led South Africa’s fight against HIV/Aids, said: “We’re going to see this occur more commonly now than in 2020, as we vaccinate and as more people are infected.”
