Novavax shares surge after drugmaker says new Covid vaccine was effective against Eris variant

Shares of Novavax jumped more than 13% on Tuesday after the biotech company said its new Covid vaccine generated a broad immune response against the now-dominant Eris variant and another fast-spreading strain of the virus in small animal trials.

The updated shot is designed to target omicron subvariant XBB.1.5, which is slowly declining nationwide. 

But the trial results suggest that the shot may still be effective against newer Covid variants gaining a greater foothold in the U.S. That includes Eris and XBB.1.16.6 – both of which are also descendants of omicron. 

Novavax's vaccine and new shots from Pfizer and Moderna are expected to roll out in the U.S. within weeks, pending potential approvals from the U.S. Food and Drug Administration. 

Both Pfizer and Moderna have also released initial trial results indicating that their shots will be effective against Eris, but Moderna is the only company with data on humans.

"We have a lot of confidence in our updated Covid vaccine and are working diligently with global regulatory bodies to ensure our protein-based vaccine is available this fall," Filip Dubovsky, Novavax's president of research and development, said in a release.

Eris and several XBB variants are fueling a slight uptick in hospitalizations and cases in the U.S., but numbers remain below the summer peak that strained hospitals last year. 

Eris, also known as EG.5, accounted for 17.3% of all cases as of Saturday, according to the Centers for Disease Control and Prevention. 

The World Health Organization designated Eris a "variant of interest," meaning it will be monitored for mutations that could make it more severe. 

XBB.1.16.6 is also beginning to surge, accounting for 8% of all cases nationwide as of Saturday, the CDC said.