Moderna CEO Says Fourth COVID-19 Dose May Be Needed Next Fall

While the booster that millions of Americans received this past fall should hold strong through this winter's omicron surge, Bancel said the efficacy of boosters will probably decline over the course of several months, similar to what happened with the first two doses.

"I will be surprised when we get that data in the coming weeks that it's holding nicely over time -- I would expect that it's not going to hold great," Bancel said of the booster shots during an interview with Goldman Sachs during its health care CEO conference, CNBC reported. Governments, including the United Kingdom and South Korea, are already ordering the doses in preparation, he added.

Moderna published preliminary data last month that showed its currently authorized 50-mcg booster shot increased the antibodies that block infection from omicron 37-fold. A 100-mcg booster increased those antibodies 83-fold.

Meanwhile, data from the United Kingdom found that the Moderna and Pfizer two-dose vaccines are only about 10 percent effective at preventing symptomatic infection from omicron 20 weeks after the second dose, CNBC reported. The same study, published by the U.K. Health Security Agency, showed that booster doses are up to 75 percent effective at preventing symptomatic infection two weeks after receiving the shot. But the strength of the booster shots starts to wane after about four weeks, the study found. Boosters were 55 to 70 percent effective at preventing infection at weeks 5 to 9 and 40 to 50 percent effective 10 weeks after receiving the shot.

Still, Bancel sounded a positive note on Thursday, saying omicron could accelerate the transition from the acute crisis caused by the coronavirus to a phase where enough people have some level of immunity so that COVID-19 no longer upends daily life.