(The Hill) — Pfizer CEO Albert Bourla said Wednesday that a fourth dose of the COVID-19 vaccine may eventually be needed amid concerns about the omicron variant.

Bourla told CNBC that he previously thought a fourth shot may be needed 12 months after the third dose, but with omicron, that timeline may need to be moved up. 

“I think we will need the fourth dose,” he said, pointing to his previous timeline of 12 months. “With omicron, we need to wait and see because we have very little information. We may need it faster.”

For now, though, the company says that three doses appear to provide good protection. Pfizer released data on Wednesday showing that a third dose led to similar levels of antibodies against omicron as two doses had against the original virus, which led to strong protection.  

For right now to get through the winter surge, “a third dose will give very good protection I believe,” Bourla said. It is unclear how durable that protection will be.

Some experts have been skeptical of the need for additional shots of the vaccine, noting that companies like Pfizer have a financial interest in selling more shots and that even two shots could still provide protection against severe disease, particularly in nonelderly people. 

Still, many experts, including the Biden administration’s health officials, have backed the idea of at least a third shot, particularly given the threat of omicron.  

One possibility is also that any fourth dose could be one specifically targeted to omicron, something Pfizer is exploring. 

As Bourla said as well, there is still the need for more data on a fourth shot’s necessity.