Biotech company Moderna released its fourth-quarter earnings Thursday and raised their 2022 guidance for COVID-19 vaccine sales by $2 billion as they expect the virus to evolve into an endemic phase and more booster shots.

Moderna raised its expected earnings from the COVID vaccine in 2022 to $19 billion from $17 billion. That $19 billion reflects the currently signed agreements, which Moderna has not signed with the U.S. government yet, according to Moderna CEO Stephane Bancel.

There have been 207 million vaccine doses administered since the Food and Drug Administration agreed to an emergency authorization of Moderna's vaccine in December 2020.

“Moderna increased its 2022 signed advance purchase agreements to approximately $19 billion, with additional signed options of approximately $3 billion; numerous discussions ongoing with governments for the fall of 2022 and 2023,” the earnings release read.

Bancel also said vaccines prices do not reflect their current value, and that he expects the prices to go up.

“Moderna believes that the SARS-CoV-2 virus will evolve to an endemic phase in 2022 and as a result, the Company expects sales to be larger in the second half of 2022 than in the first half,” the release noted.

As the virus moves into an endemic phase, booster shots every six months or so may still be necessary, like how some people get a flu shot every winter. However, the virus could also evolve into a new variant or sub-variant, as the virus's evolution cannot be predicted.

“We believe that a seasonal booster will be necessary to prevent breakthrough diseases, including hospitalization in vulnerable populations,” Moderna President Stephen Hoge told CNBC. “And we believe that the continued evolution of the virus is going to continue to put pressure on preexisting immunity.”

Moderna’s 2022 expectations differ from CVS’ expectations, which were stated in its own fourth-quarter release. CVS anticipates that there will not be a fourth COVID shot, booster, or another surge of coronavirus cases in the U.S.

Many vaccine manufacturers’ expectations of an Omicron-specific vaccine fell by the wayside because of the relatively short time the surge lasted. In an earnings call, CVS Chief Financial Officer Shawn Guertin said that the company expects there to be a decline between 70-80% in the volume of vaccines in 2022, even as younger populations become eligible.