By Sandra Rose  | 

Luis Alvarez / DigitalVision

Moderna CEO warns Americans may need a 5th mRNA booster shot in the fall since previous boosters lose effectiveness.

Stephane Bancel, the CEO of Moderna, spoke on Thursday at a Goldman Sachs conference of healthcare professionals, DailyMail.com reported.

Bancel said a 5th mRNA booster is necessary in the fall because 3rd and 4th booster shots administered this fall was "not going to hold great".

"I still believe we're going to need boosters in the fall of '22 and forward," Bancel said.

He said a vaccine in development to combat the mild Omicron variant will not be ready in the next few months.

Bancel added the elderly and those with underlying health conditions might need annual booster shots for the rest of their lives.

"We have been saying that we believe first this virus is not going away," Bancel said.

"We're going to have to live with it."

In related news, the CDC changed the definition of "fully vaccinated" to "up to date".

"We are now recommending that individuals stay up to date with additional doses that they are eligible for," said CDC Director Rochelle Walensky on Wednesday.