Pfizer CEO Albert Bourla revealed during an interview on Wednesday that he believes Americans will eventually need a fourth dose of the COVID-19 vaccine as concerns grow regarding the Omicron variant.

Bourla shared the comments during an interview on CNBC’s “Squawk Box” with Meg Tirrell and Becky Quick on Wednesday.

“Albert, Israel’s already working on fourth vaccination shots. What, what has it gotten them to that point where they think that that’s necessary and what are the results, the real world results, you’ve seen as, as a result of that?” Quick asked the Pfizer CEO.