Overview

• The CDC estimates NB.1.8.1 accounted for about 37 percent of US COVID infections as of early June, though limited sequencing yields a possible range of 13 to 68 percent.
• The World Health Organization designated NB.1.8.1 a variant under monitoring on May 23 after it was detected in at least 22 countries and US travelers at major airports.
• Researchers link the variant’s swift spread to multiple spike protein mutations that enhance transmissibility without evidence of increased disease severity.
• Current COVID vaccines are expected to remain protective against NB.1.8.1, but updated shots will be limited to older adults and people with health conditions pending new trial results.
• Public health experts warn that diminishing population immunity and the variant’s growth could trigger a new wave of infections and hospitalizations this summer.