What do we know about the British variant?
Text updated on 2021-06-23
The VoC 202012/01 variant, also known as B.1.1.7 or British variant or Alpha variant is more contagious than the non-mutated form. Extra care should be taken to avoid the risk of transmission: wear a tight-fitting mask, wash hands, ventilate living areas and avoid crowds.
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.
In this report, researchers compared 1,769 people infected with the VoC 202012/01 variant with 1,769 people infected with other forms of SARS-CoV-2. Patients in the two groups were matched by age and sex. The results show that the number of people hospitalized was not significantly different in the two groups (varying: 0.9% of patients versus 1.5% for the non-mutated form). Mortality at 28 days is not significantly different in the two groups (0.89% for the variant versus 0.73% for the non-mutated form). The reinfection rate (a positive test more than 90 days after the first infection) is not significantly different in the two groups: 2 cases for the variant versus 3 for the non-mutated form.Investigation of novel SARS-CoV-2 variant: Variant of Concern 202012/01. Technical briefing document on novel SARS-CoV-2 variant. Published 21 December 2020
In this report, the authors studied the secondary rate of infection using data routinely collected by health institutions in England. 956,519 contact cases were followed up between November 30, 2020 and December 20, 2020. Of these contact cases 121,072 (12.7%) were infected with SARS-CoV-2. The infection rate of the contact cases is about 15% when the index case (the patient who infected the contact case) was a carrier of the variant form of VoC 202012/01 and about 11% when the index case did not carry the variant.Investigation of novel SARS-CoV-2 variant: 202012/01. Technical briefing 3. 28 December 2020.
Modelling study on the expansion of the 202012/01 VoC variant, based on data routinely collected in England between October and December 2020 in patients with COVID-19. Based on data acquired from November 8 to December 19, 2020, the results show that among 0-19 year olds, the form of the 202012/01 VoC variant appears to be more present than the non-mutated form and among 60-79 year olds, the opposite is true: the non-mutated form appears to be more present. Based on data acquired between October 24 and December 12, 2020, the authors estimate that the absolute advantage of the reproduction rate of the variant over the non-mutated form varies from 0.36 to 0.68.Davies, N. G., Abbott, S., Barnard, R. C., Jarvis, C. I., Kucharski, A. J., Munday, J. D., ... & Edmunds, W. J. (2021). Estimated transmissibility and impact of SARS-CoV-2 lineage B. 1.1. 7 in England. Science.
Modelling study on data from patients with COVID-19 in the London area, East and South East England, which estimates that the VoC 202012/01 variant spreads more rapidly in South East England than pre-existing forms without the mutation and that the VoC 202012/01 variant is 56% (95% range: 50% to 74%) more transmissible than the non-mutated form of SARS-CoV-2 .Davies, N. G., Abbott, S., Barnard, R. C., Jarvis, C. I., Kucharski, A. J., Munday, J. D., ... & Edmunds, W. J. (2021). Estimated transmissibility and impact of SARS-CoV-2 lineage B. 1.1. 7 in England. Science.
The British variant could come from immunocompromised patients who have been infected with coronavirus for several months.Rambaut, A., Loman, N., Pybus, O., Barclay, W., Barrett, J., Carabelli, A., ... & Volz, E. (2020). Preliminary genomic characterisation of an emergent SARS-CoV-2 lineage in the UK defined by a novel set of spike mutations. Genom. Epidemiol.
Study conducted in the UK between October 1, 2020 and February 12, 2021 in 109,812 people over 30 years of age infected with SARS-CoV-2 and followed for 28 days. The authors compared the mortality rate in two groups of patients: a group of 54,906 people infected with the UK variant (identified by non-recognition of the Spike protein with an RT-PCR test) and a group of 54,906 people infected with the non-mutated form of SARS-CoV-2. The groups were matched for age, ethnicity, gender, socioeconomic status, and region of residence. There were 227 deaths in the group infected with the UK variant and 141 deaths in the group infected with the non-mutated form of coronavirus. For the UK variant, the rate is 4.1 deaths per 1,000 cases and for the non-mutated form the rate is 2.5 deaths per 1,000 cases, a 64% increase in mortality risk with the UK variant.Challen, R., Brooks-Pollock, E., Read, J. M., Dyson, L., Tsaneva-Atanasova, K., & Danon, L. (2021). Risk of mortality in patients infected with SARS-CoV-2 variant of concern 202012/1: matched cohort study. BMJ, 372.