New variant EG.5 is on the rise as Covid-19 cases and hospitalizations go up
By Brenda Goodman, CNN
There’s a new coronavirus variant topping the leaderboard in the United States: EG.5.
Nationally, EG.5 is causing about 17% of new Covid-19 cases in the country, compared with 16% for the next most common lineage, XBB.1.16, according to the latest estimates from the US Centers for Disease Control and Prevention.
EG may sound like a whole new flavor of the virus, but it’s not; it’s a spinoff of the XBB recombinant strain of the Omicron family. And it represents another incremental tweak to the virus rather than a major evolutionary leap like the original Omicron strain.
Compared with its parent XBB.1.9.2, it has one extra mutation to its spike, at position 465. This mutation has appeared in other coronavirus variants before. Scientists aren’t sure exactly what new tricks it enables the virus to do, but variant hunters are paying attention because many of the new XBB descendants have adopted it.
The 465 mutation is present in about 35% of coronavirus sequences reported worldwide, including another that’s rising in prevalence in the Northeast, FL.1.5.1, suggesting that it is conveying some kind of evolutionary advantage over previous versions.
EG.5 also now has its own offshoot, EG.5.1, that adds a second mutation to the spike. That one is also spreading rapidly.
Dr. David Ho has been testing these variants in his lab at Columbia University to see how resistant they have become to the antibodies we have to defend against them.
“Both are only slightly more resistant to neutralizing antibodies in serum of infected and vaccinated persons,” Ho, a professor of microbiology and immunology, said in an email to CNN.
The variant has become the most prevalent in the US just as cases, emergency room visits and hospitalizations are going up, although there’s nothing to suggest that this specific strain is what’s driving those increases.
Instead, epidemiologists think human behavior is the engine for this uptick. They point to things like record heat driving more people indoors for air conditioning, which helps the virus spread. Summer travel is sending people outside their normal social circles, which carries viruses to new victims. School is going back into session in many parts of the country too, and as parents know, homework isn’t the only thing kids bring home from their classrooms.
Topol said the vaccine is particularly important for those who are elderly and who have weakened immune systems because they no longer have effective monoclonal antibodies to help if a Covid-19 case becomes severe.
