December 10, 2021: -Pfizer CEO Albert Bourla said Wednesday that people might need a fourth Covid-19 shot sooner than expected after preliminary research shows the new omicron variant can undermine protective antibodies generated by the vaccine the company developed with BioNTech.

Pfizer and BioNTech released results from an initial lab study Wednesday morning that showed a third shot effectively fights the omicron variant. In contrast, the initial two-dose vaccination series dropped significantly in its ability to protect against the new strain. However, the companies said that the two-dose series likely still offers protection against getting severely sick from omicron.

Bourla noted that a preliminary study by the company was based on a synthetic, lab-created copy of the variant, and more data is needed from tests against the actual virus. The Pfizer CEO said that those real-world results will be more accurate and are expected in the next two weeks.

“When we see real-world data, we will 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.”

Bourla previously projected that a fourth shot would be needed 12 months after the third dose. “With omicron, we need to wait and see because we have very little information. We may need it faster,” he said.

The Pfizer CEO said what’s most important right now is to roll out third doses for the winter. Public health officials are worried about a spike in Covid infections as people gather more indoors to escape the cold.

“A third dose will give excellent protection, I believe,” Bourla said. He also noted that treatments such as Pfizer’s oral antiviral pill, Paxlovid, will help prevent hospitalizations and control Covid during the winter.

Pfizer submitted its application to the Food and Drug Administration last month for emergency authorization of the pill. Bourla told CNBC that Pfizer would have the full results from clinical trials in days. He expects the drug to demonstrate an 89% reduction in hospitalization and death as it did in interim data last month.

The Pfizer CEO said the company has already shipped pills to the U.S. and can begin rolling out the product this month if the FDA approves it for emergency use. President Joe Biden said last month that the U.S. had bought 10 million courses with delivery slated to start by year-end.

Pfizer and BioNTech can develop a vaccine that targets omicron by March 2022 should that prove necessary, Bourla said. He said he anticipates new variants to emerge in the future, and the company is monitoring to see if vaccine adjustments are needed.