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New Strain EG.5 Dominating COVID Infections in the U.S.

For the past several years, a sharp uptick in COVID-19 infections has appeared in the mid-late summer. In some years, that has correlated with the emergence of a new dominant strain. The year 2023 is following that same pattern. A new variant EG.5 is now reported to be the dominant cause of COVID-19 infections. The EG.5 strain is nicknamed Eris after the mythical Greek goddess of strife and discord. The new omicron strain appears to be closly related to the XBB variants which were more common at the beginning of the year, but had an almost “blink-and-you-miss-it” domination period. As with so many coronavirus strains, EG.5 has a specific mutation that allows it to evade human immunity from previous infection or certain vaccines. However, it’s worth noting that this is still a subvariant of omicron rather than a whole new variant overall. That in itself may ease the impact of Eris.

There is good news is that EG.5 thus far has not been the burden some previous COVID-19 strains have been. In the first week of August there were over 32,000 fewer new hospitalizations for COVID-19 compared to 2022. It does not appear to cause any more severe infections than other variants and is not (yet) associated with any new or unique symptoms. The updated COVID-19 vaccines that are set to be available in the Fall were based on the XBB 1.5 omicron subvariant. Because of the variants’ similarities, it is expected that the Fall vaccines will provide protection against EG.5 for anyone who does not become infected with the strain before the vaccines become available.  The makers of all three available COVID-19 vaccines have reported that the vaccines to be released in the fall do provide protection against EG.5.

EG.5 has too many changes  from omicron BA.5 (for which they were based on) for the current booster vaccines to provide much meaningful immunity. For the average healthy, non-immunocompromised patient, it is better to wait for these new vaccine versions to become available.  The virus appears to be following a trend seen with other respiratory viruses, where continued changes necessitate the need for annual vaccination (e.g influenza). Because of that, it is important for patients to receive the new vaccine this Fall. Even if a person is not at high risk for complications such as hospitalization, the vaccine can help reduce the potential for infection in general thereby reduce lost school or work days and time away from other activities.