What's EU.1.1? CDC Tracks More Distant Descendant Of XBB.1.5 COVID Variant
The Centers for Disease Control and Prevention (CDC) has announced that it is monitoring multiple new COVID-19 variants, further complicating the landscape of strains currently circulating nationwide. Among the variants under CDC surveillance is EU.1.1, a strain that gained attention earlier this year due to its rapid emergence in several European countries.
EU.1.1 is a more distant descendant of the XBB.1.5 variant, which saw a surge earlier this year. It possesses additional mutations in its spike protein, potentially contributing to its increased transmissibility. According to the CDC's estimates, EU.1.1 currently accounts for 1.7% of COVID-19 cases across the United States, although it may have already reached as high as 8.7% of cases in the Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming region, CBS News reported.
As of late, it remains uncertain whether EU.1.1 will result in new or different symptoms in the United States. While there have been anecdotal reports, health officials have emphasized the lack of substantial evidence indicating previous variants led to changes in the effects of COVID-19. The evolution of immunity among infected individuals over time can affect how the virus manifests, further complicating reports of symptom shifts.
Nearly all Americans are estimated to possess antibodies from vaccination, prior infection, or a combination of both. The CDC reported that an increasing proportion of hospitalizations and deaths now result from reinfections.
Utah laboratories have sequenced the highest number of EU.1.1 infections compared to other states, with the state's public health laboratory reporting nearly 100 cases to global virus databases. In contrast, neighboring Nevada and Colorado labs have only reported single-digit numbers of sequenced EU.1.1 infections.
Despite the prevalence of EU.1.1 cases in Utah, the state's overall COVID-19 trends align with the rest of the country, currently reflecting record-low levels observed during the previous spring and summer months.
A recent analysis by academic and federal modelers predicts that the United States will likely experience intermittent periods of reduced COVID-19 hospitalizations and deaths during the warmer months for at least the next two years. Subsequent peaks during the fall and winter are projected to be lower than previous records, per CBS News.
CDC data indicated that the pace of new COVID-19 hospital admissions and emergency room visits in Utah largely slowed or plateaued in recent months. Reported nursing home cases also remain significantly lower than winter peaks.
The CDC currently categorizes the majority of variants nationwide into four strains within the XBB family of SARS-CoV-2 variants. XBB.1.5, the largest strain, is projected to account for 27.0% of infections. XBB.1.9.2 and XBB.1.9.1 together make up 24.4% of cases. XBB.1.16 follows as the next largest strain, representing 19.9% of circulating viruses. XBB.2.3 accounts for 10.6% nationwide.
Earlier this month, the Food and Drug Administration (FDA) recommended that COVID-19 vaccines for the fall should be updated to target the XBB.1.5 variant. However, officials assert that the new shots will enhance immunity against all these strains and their various descendants, as they are closely related.
Moderna announced Thursday that it has formally submitted its newly revised shots for emergency use authorization, specifically designed to target XBB.1.5. The company also highlighted research suggesting that the new vaccine would generate robust immune responses capable of protecting against XBB.1.16, XBB.2.3 and their relatives.