New corona variant on the rise – now we know why Eris is so contagious

We are actually prepared for it: thanks to vaccinations and infections, our immune system produces neutralizing antibodies that attach to the spike protein and thus prevent the coronavirus from entering the cells and multiplying. But the virus fights back and develops mutations that reduce the ability of the antibodies to bind to the spike protein.

There are so many of these types of mutations and therefore new variants that you can easily get lost in the jungle of variants. In Switzerland, the Omicron variant BA.2.75 is currently on the rise and its share is 25 percent, while XBB’s dominance is declining slightly.

However, the EG.5.1 variant, named ‘Eris’ after the Greek goddess of discord and chaos, is gaining ground worldwide. It is gaining ground in the ongoing competition between the virus and the immune system. In Switzerland, the frequency is currently 33 percent, says Richard Neher, virus analyst at the Biozentrum of the University of Basel. EG.5.1 is also a descendant of the XBB variants. However, it was renamed as the names of the XBB line became increasingly complicated due to the continued branching of the omicron family tree.

This EG.5 lineage of Sars-CoV-2 has been around since May and the World Health Organization (WHO) has classified it as a “virus variant of concern”. Scientists from the Leibniz Institute for Primate Research in Göttingen now wanted to know why Eris spreads so quickly and have published the results in a study in the journal “The Lancet”.

They found that EG.5.1 is no more contagious than its predecessors. It therefore does not attack the target host cells more effectively. The reason for the increasing spread is that Eris can escape neutralizing antibodies better than other Sars-CoV-2 lineages currently in circulation. Richard Neher confirms this: “EG.5.1 has the F456L change in the spike protein, which likely allows the virus to prevent some antibodies from binding.” So Eris has a benefit for people whose immune systems have formed neutralizing antibodies after vaccination and infection – so to speak, for everyone.

Despite the ‘success of antibody escape’, it is impossible to say whether EG.5.1 will become the dominant variant. “There are a number of other variants, some of which have similar mutations. It is difficult to predict who will ultimately dominate,” says the virus analyst.

The fact that you easily become infected with Eris says little about its danger. “I am not aware that it is different in pathogenicity from other variants,” Neher said. Research leader Markus Hoffmann of the Leibnitz Institute also believes that the ability to escape antibodies is not enough to completely undermine basic immunity.

The new vaccines currently in the approval process at Swissmedic have been adapted to the XBB.1.5 variant. The Federal Office for Public Health and the Vaccination Commission recommend these vaccines for autumn vaccination. This vaccine probably also works against Eris, Neher explains. “XBB.1.5 is a direct predecessor of EG.5.1 and is therefore quite similar to XBB.1.5.”

In England there is now talk of the Pirola variant, which is being found in more and more places. Virus experts have warned about this BA.2.86 variant because it has some similar properties to the infamous Alpha variants. According to Neher, BA.2.86 was also repeatedly detected in Swiss wastewater and found in a clinical sample. “But there is no evidence that the frequency is increasing.” (aargauerzeitung.ch)