New COVID-19 Spike Mutations in Europe Put Viral Cleavage Sites Back Under Scrutiny
Nikhil Prasad Fact checked by:Thailand Medical News Team Sep 30, 2026 32 minutes ago
Newly scrutinized SARS-CoV-2 sequences from parts of Europe are putting the virus's spike cleavage machinery back in the spotlight, with several mutations appearing close to regions that can influence how efficiently the virus enters and fuses with human cells.
New COVID Spike Mutations in Europe Put Viral Cleavage Sites Back Under Scrutiny
Among the changes attracting attention are Spike A688V and S680P. None of these mutations has yet been shown to be responsible for increased COVID-19 severity in Europe. However, their location makes them important to investigate, particularly because SARS-CoV-2 has previously demonstrated that changes around its spike cleavage sites can have major biological consequences.
The clearest historical example is P681R, the furin-cleavage-site mutation that became a defining feature of the Delta variant.
Why These Spike Mutations Matter
The SARS-CoV-2 spike protein does not simply attach to a human cell and enter it. It undergoes cleavage at specific sites that helps activate the molecular machinery required for membrane fusion and infection.
One of the most important is the S1/S2 furin-cleavage site. Mutations close to this region can potentially alter how efficiently spike is processed and influence the route the virus uses to enter cells.
Both S680P and A688V occur close to this critical region and have been observed previously in SARS-CoV-2 sequence data. They are therefore not entirely new mutations suddenly appearing for the first time.
Their presence is nevertheless noteworthy if they are now being detected within evolving European sequences, particularly if changes around the cleavage region begin accumulating within the same viral genetic background.
The key issue is not simply whether these mutations exist, but what they actually do.
P681R Changed the Delta Story
During the Delta era, P681R emerged as one of the clearest examples of a spike mutation capable of altering important viral properties.
The mutation sits immediately beside the S1/S2 furin-cleavage site. Laboratory research showed that P681R increased spike cleavage and enhanced fusogenicity—the ability of viral spike to promote fusion between cellular membranes.
Delta also displayed efficient use of cell-surface entry involving TMPRSS2, rather than relying as heavily on alternative endosomal entry pathways. This phenotype was particularly important because TMPRSS2 is expressed in respiratory tissues, including cells relevant to infection of the human airway and lung.
Experimental studies subsequently linked P681R to Delta's enhanced replication and cell-fusion phenotype. Animal studies produced evidence that the mutation could contribute to pathogenicity, although the magnitude of the effect varied between experiments.
Later research added an important qualification: P681R alone could not fully reproduce Delta's disease phenotype.
When scientists examined the mutation outside Delta's complete genetic background, its effect was considerably less dram
atic. That indicated that P681R worked together with other mutations rather than acting as a single molecular switch controlling severity.
That distinction is critical when examining today's sequences.
P681R Has Not Disappeared
The mutation itself has continued to appear during subsequent SARS-CoV-2 evolution.
The European Centre for Disease Prevention and Control has monitored BA.3.2, a lineage carrying a striking group of changes around the furin-cleavage region, including N679R, P681R and A688D.
Importantly, the presence of P681R has not translated automatically into evidence of Delta-like disease severity.
ECDC has reported no evidence of increased severity associated with BA.3.2, demonstrating why the biological effects of individual mutations cannot simply be transferred from one variant to another. The surrounding viral genome matters.
A mutation capable of enhancing cleavage in one genetic background may behave differently when combined with dozens of other spike and non-spike mutations.
Could They Be Connected to Severe Cases in Europe?
That is now the question surveillance data and laboratory studies need to answer.
If parts of Europe are experiencing increases in severe COVID-19 cases, the viral genomes associated with those patients will be particularly important.
Researchers would need to establish whether lineages carrying these cleavage-associated mutations are disproportionately represented among severe cases and whether the association remains after accounting for age, previous infection, vaccination, waning immunity and underlying health risks.
Laboratory experiments would then need to determine whether the relevant combinations of mutations increase spike cleavage, fusogenicity, TMPRSS2-mediated entry, replication in airway or lung tissue, or pathogenicity in appropriate models.
Without those data, a direct connection between S680P or A688V and rising severity cannot currently be established.
A Signal Worth Watching
This
Thailand Medical News report finds that the significance of these mutations lies not in evidence that another Delta has already emerged, but in the biological territory SARS-CoV-2 is continuing to explore.
P681R demonstrated that mutations around the furin-cleavage site can influence viral entry, spike processing, fusogenicity and replication. These new mutations raises questions around another critical cleavage region, while S680P and A688V place additional changes close to the S1/S2 site.
The individual mutations may ultimately prove clinically insignificant. But if cleavage-associated changes begin accumulating within an expanding lineage at the same time that epidemiological surveillance detects increasing severe disease, the combination would demand urgent investigation.
Delta showed that changes around spike cleavage sites can matter. The unanswered question is whether SARS-CoV-2 is beginning to exploit that molecular territory again.
References:
https://www.nature.com/articles/s41586-021-04266-9
https://pmc.ncbi.nlm.nih.gov/articles/PMC8404900/
https://pubmed.ncbi.nlm.nih.gov/37043872/
https://pubmed.ncbi.nlm.nih.gov/35766497/
https://pmc.ncbi.nlm.nih.gov/articles/PMC8276844/
https://pmc.ncbi.nlm.nih.gov/articles/PMC8406809/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12316203/
https://github.com/sars-cov-2-variants/lineage-proposals/issues/2199
https://github.com/cov-lineages/pango-designation/releases
https://github.com/sars-cov-2-variants/lineage-proposals/issues/2835
https://www.ecdc.europa.eu/en/covid-19/variants-concern
New Lineages with these mutations:
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3576
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3564
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3564
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3564
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3558
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3557
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3567
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3560
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3579
https://github.com/sars-cov-2-variants/lineage-proposals/issues/3563
Read Also:
https://www.thailandmedical.news/articles/coronavirus
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