A fourth vaccine shot may be necessary sooner than originally thought.

Pfizer CEO Albert Bourla believes that people might need a fourth dose of the COVID-19 vaccine sooner than they had initially planned.

"When we see real-world data, we'll determine if the omicron is well-covered by the third dose and for how long. And the second point, I think we will need a fourth dose," Bourla told CNBC's Squawk Box on Wednesday.

Bourla had previously projected that a fourth shot of the COVID-19 vaccine would be necessary 12 months after receiving the booster. "With omicron, we need to wait and see because we have very little information. We may need it faster."

FDA GREENLIGHTS PFIZER VACCINE BOOSTERS FOR 15- and 16-YEAR-OLDS

Pfizer announced the results of preliminary trials on Wednesday, claiming that the booster shot improved one's resistance to the omicron variant "25 fold." While these results are positive, the results are based on a synthetic, lab-created version of the omicron variant. Real-world results will be more accurate and are expected to be released in the next two weeks.

That efficacy rate is why Bourla says that the most important thing is to roll out third doses this winter. "A third dose will give very good protection, I believe."

READ MORE FROM THE WASHINGTON EXAMINER

Bourla also spoke about Pfizer's oral antiviral pill, Paxlovid. Pfizer submitted its data related to Paxlovid to the Food and Drug Administration on Nov. 5 and is awaiting emergency authorization.

Federal agencies are already convinced of the pill's usefulness. The Biden administration has plans to purchase 10 million doses of Paxlovid pending the FDA's approval. Pfizer has also signed an agreement with an UN-approved nonprofit organization to provide instructions to produce Paxlovid in 95 countries for low-income communities.

The FDA greenlit the use of Pfizer vaccine boosters on Thursday.