Moderna says booster dose of its COVID-19 vaccine appears protective vs. Omicron

The vaccine maker said the decision to focus on the current vaccine, mRNA-1273, was driven in part by how quickly the recently discovered variant is spreading. The company said it still plans to develop a vaccine to protect against Omicron and hopes to advance into clinical trials early next year.

Moderna's shares were up about 6.5% at $314.42 in premarket trade.

"What we have available right now is 1273," Dr. Paul Burton, Moderna's Chief Medical Officer, said in an interview. "It's highly effective, and it's extremely safe. I think it will protect people through the coming holiday period and through these winter months, when we're going to see the most severe pressure of Omicron."

The company said a two-dose course of its vaccine generated low neutralizing antibodies against the Omicron variant, but a 50 microgram booster dose increased neutralizing antibodies against the variant 37 fold. A higher, 100 microgram booster dose of the same vaccine drove antibody levels even higher - more than 80 times pre-boost levels.