Moderna Inc is on track to deliver between 600 million and 1 billion doses of its Covid-19 vaccine this year, Chief Executive Stephane Bancel said on Thursday.

Bancel said Moderna had orders for 500 million doses of its vaccine and could comfortably make at least 600 million doses. He told a conference that the group was working to meet or even exceed a target for 1 billion doses, however.

Bancel said it was still not clear how long the antibodies generated by the vaccines would last, but added that it could potentially be a couple of years.

To note, American Armenian businessman Noubar Afeyan is the co-founder and chairman Moderna Inc.