We don’t know if the ‘Nigerian variant’ is more deadly
21 April 2021
What was claimed
The so-called “Nigerian variant” of Covid-19 is twice as deadly as the dominant “Kent variant”.
This reflects the number of deaths among the small number of cases from the “Nigerian variant” detected so far. At the time of writing there is not enough data to know whether this variant is more deadly or not.
The data in this piece is correct as of the time of publishing, on 21 April 2021.
Articles fromnewsoutlets, and posts on socialmedia have raised concerns about the risk posed by a Covid-19 variant which has been dubbed the “Nigerian variant” (although evidence now suggests that the variant was first detected in the UK). It is officially known as B1.525, or VUI202102/03 by Public Health England (PHE).
Kent Live reported that this strain kills “twice as many people” as other variants, claiming that it has “so far” killed 4.3% of the people it has infected. This is compared with 2.3% of infected people being killed by the Kent variant, which is now the most common strain in the UK.
This is misleading, because we don’t know the true number of people so far infected by either variant. Instead, these death rates are based on the number of deaths occurring among detected cases—and only 328 cases of the B1.525 variant have been found so far, which makes it hard to be confident about how deadly it is. Public Health England (PHE) said in February there was no evidence that this variant causes more severe illness or increased transmissibility.
Kent Live also reported on concerns that this strain may be better at evading the protection of vaccines because it carries the E484K mutation. This mutation impacts the ‘spike protein’ on the outside of the SARS-CoV-2 virus (which causes Covid-19) which may help it to ‘slip past’ the body's immune system. This has been demonstratedinlabstudies, but so far humanstudies have shown mixed results.
From figures up until the end of March, there had been 12 recorded deaths in the UK from this variant of Covid-19.
PHE said in February: “There is currently no evidence that this set of mutations [in B1.525] causes more severe illness or increased transmissibility.”
At the time of writing, thisvariant of Covid-19 is classified as a “Variant under Investigation”. It possesses several genetic mutations, including the E484K spike protein mutation, which is present on a number of other variants.
It is common for the genes of viruses to mutate over time, and most mutations make little difference.
an increase in transmissibility or other detrimental change in epidemiology
an increase in virulence or change in clinical disease presentation
escape from immunity derived from natural infection
a decrease in effectiveness of public health or clinical countermeasures, including vaccination, treatment in current clinical use, or testing if the impact is such that it is not easily mitigated by standard laboratory quality and regulatory measures
At the time of writing, the B1.525 variant has not met these criteria, and is classed instead as a Variant Under Investigation. This means it has mutations which may cause these problems, according to existing evidence, and there is evidence of community transmission of the variant in the UK or abroad.This may change following future risk assessments.
Where do the comparative mortality figures come from?
The reported figures come from a PHE report into the Covid-19 Variants of Concern and Under Investigation published on 1 April 2021.
Although from these numbers it appears fair to compare the case fatality rates between the two variants and conclude that B1.525 “kills twice as many people”, it is important to be aware of the context behind the two figures.
The Kent variant (or B1.1.7) case fatality rate is based on 151, 344 cases and 3,504 deaths, whereas the rate for the B1.525 variant is based on 277 cases and 12 deaths recorded at the time.
This is a much smaller number and means that the case fatality rate is much more likely to fluctuate even with small changes to the numbers of deaths. Percentages based on such small numbers are therefore very uncertain.
In addition, because we don’t know the true total number of people infected so far, these death rates are based on the number of deaths occurring among detected cases. This is another reason to treat these figures with caution.
What about the vaccines?
One of the mutations that the B1.525 variant carries is the E484K mutationwhich affects the “spike protein” on the virus surface. There is concern that this mutation may confer some resistance to the Covid-19 vaccines.
Labstudieshaveshownthat antibodies are less able to react to variants with the E484K mutation. It is not certain, however, what degree of impact this will have in humans in the real world, and studies are ongoing.
Research is also underway to updatecurrent vaccine technology to make them more effective against the mutations.
This article is part of our work fact checking potentially false pictures, videos and stories on Facebook. You can read more about this—and find out how to report Facebook content—here.
For the purposes of that scheme, we’ve rated this claim as missing context
because it is true that the case fatality rate for this variant is higher, but this is not something we can say with confidence, because only a small number of cases have been detected so far.