September 18, 2024

expert comment on XEC COVID-19 variant

Scientists comment on the new COVID-19 variant, XEC.

Prof Francois Balloux, Professor of Computational Systems Biology and Director, UCL Genetics Institute, UCL, said:

What is XEC?

“XEC is a likely recombinant between the subvariants KP.3.3 and KS.1.1. The latter are just two among the myriad sub-lineages descendant from the BA.2.86 (“Pirola”) variant that emerged about a year ago and has remained dominant for nearly a year now. XEC has first been identified in June this year in Germany and has been slowly going up in frequency since then. 

How many cases (and where)?

“There have been over 500 XEC cases sequenced so far. XEC is most common in Central Europe at this stage where it represents over 10% of all Covid infections. It remains less common in other parts of the world but seems to be going up in frequency globally. 

How worrying is this new variant?

“XEC has a slight transmission advantage over other SARS-CoV-2 currently in circulation, but protection provided by vaccines and prior SARS-CoV-2 infections against severe symptoms remains in place.

Are we expecting an XEC surge?

“It is anticipated that SARS-CoV-2 case numbers will again increase during the coming winter. At the moment, case numbers are flatlining or going down in most places. The XEC subvariant is not fuelling a surge, and is not anticipated to cause the next wave, but when cases will go up, it may well represent a sizeable proportion of SARS-CoV-2 infections.

How much might is spread?

“It is possible that XEC will become the dominant subvariant over the winter. Similar shifts have been observed before with JN.1 having become the dominant BA.2.86 sub-lineage in the winter 2023/24. XEC represents a fairly minor evolution relative to the SARS-CoV-2 diversity currently in circulation, and is not a highly derived novel variant such as those that were granted Greek letters (Alpha – Omicron), or even Omicron BA.2.86 (“Pirola”).

What do we know about symptoms?

“There is no evidence that XEC symptoms may differ from those caused by any other SARS-CoV-2 lineage currently in circulation. It is not anticipated that XEC will cause different symptoms.”

Declared interests

For all other experts, no reply to our request for DOIs was received.