Researchers published a study in the New England Journal of Medicine on Wednesday that concluded a booster dose of the vaccine resulted in “improved durability” against the variant. However, it noted, antibodies waned notably six months after that booster, dropping sixfold.

Dr. Paul Burton, Moderna’s CMO, told CNN that was good news in the short term, but it had longer implications that will need to be monitored. And he seemed to begin making the case for another round of boosters this year.

“Vaccination and boosting almost obliterates [the Omicron] risk,” Burton said. “But, what we see by six months is that those levels begin to fall. And if you project that out and you make the conclusion that they will continue to fall, we know that probably by the autumn of this coming year, in 2022, that those levels will be down to an area where people may not have protection.”

Moderna has launched a Phase 2 clinical trial of an Omicron-specific booster. Burton said he expects, barring unforeseen problems, the company should be ready to begin wide-scale manufacturing by the middle of the year.

It’s unknown if that booster will also protect against the BA.2 sub-variant, which has been dubbed “stealth Omicron.”

About 63% of the U.S. population is fully vaccinated, and just 25% have received a booster dose, according to Bloomberg’s vaccine tracker. That compares to a 72% fully vaccinated rate in the EU, with 43% having received boosters.