“In [the] next couple weeks, supply will increase from 5 million to 10 million doses per week,” Bourla told a briefing at drug maker’s plant in Kalamazoo, Michigan, which Biden toured on Friday.

Biden, addressing media and other visitors to the plant, said his administration was on track with its goal to vaccinate 100 million Americans in its first 100 days, and also distribute 600 million doses by July 29.

“The United States will have enough vaccine for public by end of July,” Biden said.

Earlier on Friday, US Centers for Disease Control and Prevention (CDC) Director Rochelle Walensky said the United States has vaccinated 41 million Americans since December 14, and save for a few who experienced some common after-effects, there had been no reason for concern.

White House coronavirus response adviser Andy Slavitt said the United States was experiencing a backlog in the delivery of 6 million coronavirus vaccines due to bad weather this week.

“The 6 million doses represent about three days of delayed shipping. But 1.4 million doses are already in transit. We anticipate all the backlogged doses will be delivered next week, with most being delivered within the next several days. We will be able to catch up,” Slavitt added.