What do we know about the British variant?

The Alpha variant, VoC 202012/01 (Variant of Concern 202012/01) or lineage B.1.1.7 known as the UK variant was first described in the UK in September 2020. It contains 17 non-synonymous mutations (i.e. mutations that affect the virus' proteins), 8 of which modify the Spike protein. This number and combination of mutations is unusual. In particular, there is the N501Y mutation, which is also found in the variant identified in South Africa in December 2020 (see the question, Which coronavirus variants SARS-CoV-2 have attracted attention?) and which could increase the affinity of the Spike protein for the ACE2 receptor. This variant contains another mutation, P681H, which is located at a particular site within the Spike protein, at the furin cleavage site. This particular site facilitates fusion between the virus membrane and the cell membrane. This furin cleavage site, which does not exist in other coronaviruses related to SARS-CoV-2, promotes coronavirus entry into respiratory epithelial cells. This variant also presents a deletion, 69-70del, which has already been described in the Cluster 5 variant (see question, What variants of the SARS-CoV-2 coronavirus have attracted attention?) and which could allow the coronavirus to escape the immune system. These mutations have already been described in other variants of SARS-CoV-2 but this is the only one that cumulates all these mutations.

What is special about this Alpha variant?

This variant was detected in September 2020 in Kent in the UK and then spread rapidly to the south of the UK. In London, the variant was detected in 28% of infections in November 2020, and in 60% in January 2021. In the UK, the presence of this variant was correlated with an increase in the rate of infection. In March 2021, the variant was detected in 94 countries (Europe, North and South America, Africa, Asia, Oceania). Results from recent studies suggest that this variant may have an effect on disease severity and increase mortality. There is evidence that this variant is more contagious. With the restrictions in place in March 2021, one person infected with a non-mutated form of the coronavirus infects approximately 1 person. Since the reproduction rate of the Alpha variant is between 0.4 and 0.7 higher, this means that one person infected with the variant will infect between 1.4 and 1.7 people.

How did the Alpha variant come about?

A large number of mutations separate the British variant from other circulating forms of the SARS-CoV-2 coronavirus. This suggests that this variant appeared in an immunocompromised patient (i.e., a person with a weaker than average immune system) who was infected with the coronavirus for several months. A weakened immune system allows the virus to multiply more and accumulate more mutations. Indeed, high rates of mutation accumulation over short periods of time have been observed in immunocompromised or immunocompromised patients.

Since the Alpha variant appeared, it has been accumulating mutations at a rate comparable to other forms of the virus, with about 1-2 new mutations per month. The speed of evolution of the coronavirus has therefore not changed between this variant and its predecessors. 

What to do about variant Alpha?

To avoid catching the coronavirus, slow down the spread of COVID-19, and limit the transmission of variants that may be more transmissible, it is very important for everyone to be extremely vigilant. A well-fitting, well-filtering mask should be worn on the face (see question Why put on a mask? and the question Surgical mask or fabric mask: which to choose?). Safety distances must be respected, hands must be washed regularly, the premises must be ventilated as often as possible with outside air, and of course crowds must be avoided.