I'd like to shift gears, then. I'd like to come back to Ms. Sampson, since I believe that about two-thirds of the vaccines administered in Canada were from Pfizer.
I was wondering if you could give us some insight as to the timeline of the signing of these contracts. It was reported in the media that Pfizer signed its advance purchase agreement with the Government of Canada on October 26, 2020, but the contract with the United States was signed about three months earlier, on July 22, 2020. Can you explain how it came about that the contract with the United States was signed three months before the contract with Canada?