People who received a third dose of the Pfizer-BioNTech coronavirus vaccine elicited a stronger immune response to the delta variant compared to those who only completed the two-dose regimen, the company told federal regulators on Monday.

“The data we’ve seen to date suggest a third dose of our vaccine elicits antibody levels that significantly exceed those seen after the two-dose primary schedule,” said Pfizer CEO Albert Bourla. “We are pleased to submit these data to the FDA as we continue working together to address the evolving challenges of this pandemic.”