New Variant of COVID-19, EG.5, Spreads Rapidly, Raises Concerns
A highly infectious variant of COVID-19, known as EG.5, is spreading rapidly across the world, posing new challenges in the fight against the pandemic. EG.5, a descendant of the XBB strain of Omicron, was first detected in Indonesia in February and has since been steadily spreading. The variant gained attention from the World Health Organization (WHO) when infections surged in mid-June due to increased travel and high temperatures forcing people indoors. On August 9, the WHO designated EG.5 as a “variant of interest,” alongside other highly contagious Omicron variants.
Rajendram Rajnarayanan, a computational biologist at the New York Institute of Technology, warns that EG.5 is a significant concern based on past experiences with similar variants. In the United States, EG.5 has become the most prevalent strain of SARS-CoV-2, replacing other XBB variants. Data from the Centers for Disease Control and Prevention (CDC) shows that EG.5 is responsible for more than 17 percent of reported COVID-19 cases in the country, leading to a 12.5 percent increase in hospitalizations.
EG.5 is also causing an uptick in COVID-19 cases globally. Between July 10 and August 6, there were nearly 1.5 million new cases, an 80 percent increase compared to the previous 28 days. The variant has been detected in 51 other countries, including those with high vaccination rates like Canada, Japan, South Korea, and China.
Experts, including virologist Angela Rasmussen, emphasize the need to take EG.5 and other subvariants seriously. Rajnarayanan suggests using testing kits to identify COVID-19 cases, wearing masks, and staying home if positive to slow the spread of the new variant.
EG.5 is a branch of the Omicron variant, which emerged in 2022. It is the fastest-spreading SARS-CoV-2 variant and can overcome immunity gained from vaccination or previous breakthrough infections. The variant differs from its parent, XBB, by a single change in its spike protein, which allows the virus to enter human cells. Preliminary research from Japan shows that EG.5 is about 20 percent more contagious than XBB.1.5.
Tracking the exact prevalence of EG.5 is challenging due to limited sequencing of positive samples and reduced reporting of non-hospitalized cases. However, wastewater monitoring and hospitalization data provide some insight into the variant’s impact. Scientists, like Rajnarayanan, analyze this data to visualize the daily prevalence of circulating variants. Wastewater samples across the United States have shown a tripling of the virus concentration since the end of June.
Scientists are still studying whether EG.5 can evade prior immunity. Research from Japan suggests that EG.5 can be suppressed by immunity gained from prior Omicron subvariant infections. However, preliminary studies from China indicate that EG.5-like spikes created in the lab can dodge or weaken XBB.1.5 antibodies. More data and peer review are needed to confirm these findings.
Experts reassure the public that current vaccines, as well as the proposed fall boosters, can prevent severe complications from COVID-19, even if the new variants may slightly weaken their effectiveness. The boosters are expected to target XBB.1.5, the previous prevailing variant. The CDC director anticipates the availability of booster doses in early October. Experts believe that the booster should provide broad protection against EG.5 and other Omicron variants.
The WHO states that there is no indication to suggest that EG.5 causes more severe disease compared to other recent variants of interest. However, the rapid spread of EG.5 raises concerns about a potential fall surge in cases, particularly among vulnerable populations. The number of COVID cases among nursing home residents has been steadily increasing, and unvaccinated individuals remain at higher risk. Health experts urge the most vulnerable populations to get vaccinated and receive the booster when it becomes available to protect themselves against this highly contagious variant.