(The Hill) – The COVID-19 omicron subvariant EG.5 is currently the most dominant strain in the U.S. according to the Centers for Disease Control and Prevention (CDC) genomic surveillance data. However, due to limited data collection, it is difficult to fully understand the impact of this on the country.
According to the CDC data, the EG.5 omicron subvariant accounts for 17.3 percent of COVID-19 infections in the U.S., which increased by 5 percent in the two weeks prior to the last update.
Currently, the prevalence of EG.5 is relatively minor compared to the second most prevalent strain, XBB.1.16, which accounts for 15.6 percent of cases.
While the CDC no longer tracks national COVID-19 case rates, regular updates are still provided for hospitalization data (source). Recent data shows a slight increase in hospitalizations due to SARS-CoV-2, indicating higher transmission levels. However, it is unclear if this can be attributed solely to the recent growth of the EG.5 subvariant.
Since the end of the national public health emergency for COVID-19, comprehensive viral data collection has become limited. The CDC currently only has genomic data from three out of the ten regions under the Department of Health and Human Services (HHS).
EG.5 is predominantly found in Region 4, which includes much of the Southeast, among the three regions with available genomic data.
EG.5 belongs to the XBB family of omicron subvariants, originating from the XBB.1.9.2 strain. Previously, the XBB.1.5 subvariant held dominance in the U.S. for several months before being briefly surpassed by XBB.1.16 in July.
According to the World Health Organization (WHO), EG.5 was initially detected in February of this year. It has been classified as a “variant under monitoring” by the WHO, suggesting genetic differences that may indicate potential advantages in growth compared to other circulating strains, although further assessment is needed.
This classification separates EG.5 from variants of concern, which have a significant impact on healthcare systems, as well as variants of interest associated with increasing cases or other epidemiological risks.
The genetic similarity between the dominant EG.5 strain and XBB.1.5 may be advantageous for the U.S. as it prepares for a fall COVID-19 vaccine campaign. Vaccine manufacturers are developing updated shots targeting XBB.1.5, as it was the predominant strain when health advisory committees made their selection for the upcoming season.
While XBB.1.5 may not be the most widely circulating strain this fall, health officials anticipate that the vaccine will still provide strong cross-protection against severe disease and hospitalization for the most prevalent strain.