A: Move over XBB, there is a new Omicron kid in town.
TL;DR: A new subvariant called 🥚EG. 5 is growing as a fraction of new COVID infections.
🥚 So far there is no reason to believe this variant causes more (or less) severe disease
🥚 The new XBB boosters should still be a decent match since they are close relatives.
The EG.5 variant has recently taken over as the most common circulating variant in the US and UK and is growing as a fraction of infections in other countries. EG.5 is still a descendant of Omicron, but on a slightly different branch of the family tree from the recently dominant XBB subvariants.
Being the “most common” right now doesn’t mean EG.5 makes up most infections (yet), because there are still lots of other subvariants circulating. At the end of last week, EG.5 made up 17.3% of sequences in the US, but XBB.1.6 still makes up 15.6%, with other mostly XBB subvariants making up the remainder. But EG.5 seems to have a “growth advantage” and will likely continue to grow as a fraction of overall COVID cases.
❓Should I be concerned about this variant? Is it going to fuel a new wave?
It’s important to remember that new variants are to be expected—it’s the virus being a virus. Mutations happen regularly when the virus makes copies of itself, and most are irrelevant. But occasionally a mutation gets lucky enough to give the variant an advantage over the others. EG.5 has a mutation on the spike protein that seems to reduce the effectiveness of existing antibodies. This is a common pattern with SARS-CoV-2 variants… the new kids on the block must get around our immune defenses to some extent in order to succeed and spread.
EG.5 is not a huge proportion of infections yet so can’t be solely responsible for the recent uptick in cases. The new wave probably reflects a lot of things including the cycle of waning immunity from previous waves. So far, we’re not expecting a new wave the size of previous “breakthrough” variants such as the original Omicron. First, EG.5 not very different from the recently circulating variants. More importantly, there are virtually no immune naïve people left (people with no previous infection, vaccine, or both)—which is very different from when Omicron first came blasting onto the scene.
For now, there is no suggestion that EG.5 is causing more severe disease, but this is something that we look out for as far as hospitalizations, ICU admissions, and deaths.
❓Will the updated boosters work against EG.5?
Fortunately, EG.5 is still closely related to the XBB variant that will be the target of updated vaccines. This means the updated boosters should still give strong protection against any infection in the short term, and an excellent boost in protection against severe disease in the medium to longer term. Those Nerdy Girls will be rolling up our sleeves for that protection this fall.
As always, we will keep you posted on new developments. Remember no matter the variant, your trusty prevention measures like masking and improving ventilation still work… new variants don’t defy the laws of physics!
Stay safe, stay well.
Love,
Those Nerdy Girls
Links:
“Latest COVID mutation EG.5 seems to be driving a recent surge in cases”
“What to know about EG.5, the most prevalent covid subvariant in the U.S.”
