Introducing ‘Eris,’ a major US COVID variant believed to be causing a surge in infections and hospitalizations this summer.

Introducing 'Eris,' a major US COVID variant believed to be causing a surge in infections and hospitalizations this summer.

The Rise of EG.5: A Variant Under Monitoring

EG.5 Variant

Reports of the EG.5 variant of COVID-19 have been steadily increasing, leading the World Health Organization (WHO) to designate it as a “variant under monitoring.” Detected in 45 countries across the globe, the number of cases nearly doubled from mid-June to mid-July, as stated in an Aug. 3 WHO situation report1.

In the United States, EG.5 and its related variants have become the most common strains of the virus, according to the latest projections from the U.S. Centers for Disease Control and Prevention (CDC). Approximately 17.3% of COVID-19 cases in the country are now attributed to the EG.5 viral family2. This surge in cases has led to a notable increase of nearly 13% in COVID-19 hospitalizations over the past two weeks3. Even levels of the virus in wastewater have seen a half-wave peak, although it remains relatively small4.

One particular EG.5 variant that the experts are closely observing is EG.5.1, fondly referred to as “Eris” by variant trackers. It has gained substantial momentum in the United States, accounting for almost 8.5% of sequenced cases over the past three weeks. According to the Global Initiative on Sharing All Influenza Data (GISAID), which tracks changes in COVID-19 and the flu virus globally, EG.5.1 is also increasing in Europe and Asia5.

With testing and sequencing currently at all-time lows, it is challenging to determine conclusively whether EG.5.1 is the primary factor driving the recent rise in cases. However, Dr. Eric Topol, a renowned professor of molecular medicine, warns that the variant does not appear to be benign6.

In various regions, including New York City, there is already an uptick in COVID-19 cases, suggesting that similar increases may occur in other parts of the country. Talia Quandelacy, an assistant professor of epidemiology at the Colorado School of Public Health, supports this expectation7. She also cautions that if there are no prior increases due to another variant, an upswing in COVID-19 cases during the flu season (October to May) could be a possibility8.

Determining the symptom profile of EG.5.1 and distinguishing it from other Omicron strains is still too early to ascertain. Ryan Gregory, a biology professor at the University of Guelph, suggests that although there may be a return to a high baseline of cases, it may not result in a massive wave9. Gregory has assigned catchy “street names” to noteworthy variants since the WHO discontinued using Greek letters to label them10. He humorously characterizes the past year as one of a rising sea level rather than tsunamis.

Boosters as a Defense Against EG.5

Efforts are underway to develop updated COVID-19 boosters that target the XBB.1.5 strain. Reports indicate that these boosters may not be ready until late September11. Nevertheless, experts believe that these new boosters should still be effective against EG.5 and its related variants12. The CDC has yet to issue recommendations regarding who should receive the new jab and when13.

Dr. Topol expresses concerns about the impact of delayed distribution on immunocompromised and elderly individuals. For these vulnerable populations, it is not ideal that the only available booster, the Omicron BA.4/BA.5, launched around Labor Day last year, is not as closely matched to the currently circulating strains as the upcoming booster will be14. He emphasizes the timing aspect, alerting that waiting until September or October, when schools have already resumed, and wastewater levels are rising, may lead to a brewing wave of infections15.

However, many experts, including Gregory and Rajnarayanan, worry that a substantial number of Americans may choose to forgo the new boosters. A survey conducted by the CDC suggests that only 27% of adults and 18.5% of adolescents had received an Omicron booster by late last year16. With the official end of the global pandemic emergency, fewer individuals may be motivated to take the vaccines17.

In conclusion, the EG.5 variant and its various offshoots have become the dominant strains of COVID-19 worldwide. The rise of EG.5.1, also known as “Eris,” is being closely monitored due to its significant impact in various regions. As the number of COVID-19 cases increases across the United States, experts are concerned about the potential consequences, especially considering the upcoming flu season. Efforts are underway to develop updated boosters to combat EG.5 and related variants, but delays in distribution could jeopardize the vulnerable populations, such as the immunocompromised and elderly. The decision of individuals to receive these boosters will play a crucial role in containing the spread of the virus and mitigating the potential risks posed by EG.5.


  1. Source: Fortune↩︎

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