New Covid vaccines developed by Pfizer, Moderna, and Novavax are expected to offer protection against the emerging “Eris” variant, which has become the dominant strain of the virus in the US. While the new vaccines were designed to target the omicron subvariant XBB.1.5, health experts and preliminary data suggest that they will likely still be effective against Eris (EG.5) and other widely circulating variants that are descendants of omicron.
The new vaccines are pending approval from the Food and Drug Administration (FDA), and the Centers for Disease Control and Prevention (CDC) also need to determine the appropriate recipients and dosing schedule. Nonetheless, the pending arrival of these vaccines provides reassurance as Eris and other variants contribute to a slight increase in Covid cases and hospitalizations in the US, although they remain below the levels seen during the previous summer peak.
Eris currently accounts for around 17.3% of all Covid cases in the US, surpassing the XBB.1.5 variant. While Eris has been designated a “variant of interest” by the World Health Organization, experts do not believe it poses a significant threat compared to other omicron variants circulating in the US.
The reason the new vaccines are likely effective against Eris is that the genetic makeup of Eris is very similar to the XBB.1.5 variant. Despite a minor difference in amino acid mutations, experts expect the vaccines to provide substantial protection due to the shared omicron lineage.
Moderna has reported that its updated vaccine led to a significant boost in protective antibodies against Eris and another spreading strain called “Fornax.” Pfizer and Novavax also anticipate that their updated vaccines will be effective against Eris due to the similarity between the strains.
While the decision to wait for the new vaccines or opt for currently available Covid boosters depends on individual circumstances and risk levels, experts generally suggest that most healthy individuals can wait for the new vaccines. However, unvaccinated or immunocompromised individuals who haven’t received boosters may consider taking them now to mitigate the risk of severe illness from Covid.
